2.1 Statistical study design
Statistical data analysis systems are a modern, effective tool for statistical research. Special statistical analysis systems have ample opportunities for processing statistical data, as well as universal means– Excel, Matlab, Mathcad, etc.
But even the most advanced tool cannot replace the researcher, who must formulate the purpose of the study, collect data, select methods, approaches, models and tools for processing and analyzing data, and interpret the results obtained.
Figure 2.1 shows a diagram of the statistical study.
Fig. 2.1 - Schematic diagram of statistical research
The starting point of statistical research is the formulation of the problem. When determining it, the purpose of the study is taken into account, what information is needed and how it will be used when making a decision is determined.
The statistical study itself begins with the preparatory stage. During preparatory stage analysts are studying technical task– a document drawn up by the customer of the study. The terms of reference must clearly state the objectives of the research:
the object of research is determined;
assumptions and hypotheses that must be confirmed or refuted during the study are listed;
describes how the research results will be used;
the time frame within which the study must be carried out and the budget for the study.
Based on the technical specifications, it is developed analytical report structure- That, in any form the results of the study must be presented, as well as statistical observation program. The program is a list of signs that must be recorded during the observation process (or questions to which reliable answers must be obtained for each surveyed observation unit). The content of the program is determined both by the characteristics of the observed object and the objectives of the study, as well as by the methods chosen by analysts for further processing of the collected information.
The main stage of statistical research includes the collection of necessary data and their analysis.
The final stage of the research is drawing up an analytical report and submitting it to the customer.
In Fig. Figure 2.2 presents a diagram of statistical data analysis.
Fig.2.2 – Main stages of statistical analysis
2.2 Collection of statistical information
Collecting materials involves analyzing the technical specifications of the study, identifying sources of necessary information and (if necessary) developing questionnaires. When researching sources of information, all required data is divided into primary(data that is not available and must be collected directly for this study), and secondary(previously collected for other purposes).
Secondary data collection is often referred to as “desk” or “library” research.
Examples of collecting primary data: observing store visitors, surveying hospital patients, discussing a problem at a meeting.
Secondary data is divided into internal and external.
Examples of internal secondary data sources:
information system of the organization (including an accounting subsystem, a sales management subsystem, CRM (CRM system, short for Customer Relationship Management) - application software for organizations designed to automate strategies for interacting with customers) and others);
previous studies;
written reports from employees.
Examples of external secondary data sources:
reports from statistical bodies and other government agencies;
reports from marketing agencies, professional associations, etc.;
electronic databases (address directories, GIS, etc.);
libraries;
mass media.
The main outputs at the data collection stage are:
planned sample size;
sample structure (presence and size of quotas);
type of statistical observation (data collection, survey, questionnaire, measurement, experiment, examination, etc.);
information about survey parameters (for example, the possibility of falsification of questionnaires);
scheme for encoding variables in the database of the program selected for processing;
data conversion plan;
plan diagram of the statistical procedures used.
This same stage includes the survey procedure itself. Of course, questionnaires are developed only to obtain primary information.
The received data must be edited and prepared accordingly. Each questionnaire or observation form is checked and, if necessary, adjusted. Each answer is assigned numeric or letter codes - the information is encoded. Data preparation includes editing, transcribing and checking data, coding and necessary transformations.
2.3 Determination of sample characteristics
As a rule, data collected as a result of statistical observation for statistical analysis is a sample population. The sequence of data transformation into the process of statistical research can be schematically represented as follows (Fig. 2.3)
Fig 2.3 Statistical data conversion scheme
By analyzing a sample, it is possible to draw conclusions about the population represented by the sample.
Final determination of general sampling parameters produced when all the questionnaires have been collected. It includes:
determining the actual number of respondents,
determination of the sampling structure,
distribution by survey location,
establishing a confidence level for the statistical reliability of the sample,
calculation of statistical error and determination of sample representativeness.
Real quantity respondents may turn out to be more or less than planned. The first option is better for analysis, but is disadvantageous for the customer of the research. The second may have a negative impact on the quality of the research, and, therefore, is not beneficial for either analysts or customers.
Sampling structure may be random or non-random (respondents were selected based on a previously known criterion, for example, by the quota method). Random samples are a priori representative. Non-random samples may be intentionally unrepresentative of the population but provide important information for research. In this case, you should also carefully consider the filtering questions of the questionnaire, which are designed specifically to filter out respondents who do not meet the requirements.
For determining the accuracy of the assessment First of all, it is necessary to set the confidence level (95% or 99%). Then the maximum statistical error sample is calculated as
or 
,
Where 
- sample size, 
- the probability of the occurrence of the event under study (the respondent being included in the sample), 
- the probability of the opposite event (the respondent not being included in the sample), 
- confidence coefficient, 
- variance of the characteristic.
Table 2.4 shows the most commonly used values of confidence probability and confidence coefficients.
Table 2.4
2.5 Data processing on a computer
Analyzing data using a computer involves performing a number of necessary steps.
1. Determination of the structure of the source data.
2. Entering data into the computer in accordance with its structure and program requirements. Editing and converting data.
3. Specifying a data processing method in accordance with the objectives of the study.
4. Obtaining the result of data processing. Editing it and saving it in the required format.
5. Interpretation of the processing result.
Steps 1 (preparatory) and 5 (final) are not capable of being completed by anyone. computer program- the researcher does them himself. Steps 2-4 are performed by the researcher using the program, but it is the researcher who determines the necessary procedures for editing and transforming data, methods of data processing, as well as the format for presenting the processing results. The computer's help (steps 2–4) ultimately involves moving from a long sequence of numbers to a more compact one. At the “input” of the computer, the researcher submits an array of initial data that is inaccessible to comprehension, but suitable for computer processing (step 2). Then the researcher gives the program a command to process the data in accordance with the task and data structure (step 3). At the “output”, he receives the result of processing (step 4) - also an array of data, only smaller, accessible to comprehension and meaningful interpretation. At the same time, an exhaustive analysis of data usually requires repeated processing using different methods.
2.6 Selecting a data analysis strategy
The choice of strategy for analyzing the collected data is based on knowledge of theoretical and practical aspects subject area under study, specifics and known characteristics of information, properties of specific statistical methods, as well as the experiences and perspectives of the researcher.
It must be remembered that data analysis is not the final goal of the study. Its goal is to obtain information that will help solve a specific problem and take adequate management decisions. The choice of analysis strategy should begin with an examination of the results of the previous stages of the process: defining the problem and developing a research plan. A preliminary data analysis plan developed as one element of a research plan is used as a “draft”. Then, as additional information becomes available at later stages of the research process, certain changes may need to be made.
Statistical methods are divided into one- and multivariate. Univariate methods are used when all elements of the sample are assessed by one indicator, or if there are several of these indicators for each element, but each variable is analyzed separately from all the others.
Multivariate techniques are excellent for data analysis when two or more measures are used to evaluate each sample element and these variables are analyzed simultaneously. Such methods are used to determine dependencies between phenomena.
Multivariate methods differ from univariate methods primarily in that when they are used, the focus of attention shifts from the levels (averages) and distributions (variances) of phenomena and focuses on the degree of relationship (correlation or covariance) between these phenomena.
Univariate methods can be classified based on whether the data being analyzed is metric or non-metric (Figure 3). Metric data is measured on an interval scale or a relative scale. Nonmetric data is assessed on a nominal or ordinal scale
Additionally, these methods are divided into classes based on how many samples—one, two, or more—are analyzed in the study.
The classification of one-dimensional statistical methods is presented in Fig. 2.4.
Rice. 2.4 Classification of univariate statistical methods depending on the analyzed data
The number of samples is determined by how the data is handled for a particular analysis, not by how the data was collected. For example, data on males and females can be obtained within the same sample, but if the analysis is aimed at identifying differences in perception based on gender differences, the researcher will have to operate with two different samples. Samples are considered independent if they are not experimentally related to each other. Measurements taken in one sample do not affect the values of variables in another. For analysis, data from different groups of respondents, such as those collected from females and males, are usually treated as independent samples.
On the other hand, if the data from two samples refer to the same group of respondents, the samples are considered paired - dependent.
If there is only one sample of metric data, z-test and t-test can be used. If there are two or more independent samples, in the first case you can use the z- and t-test for two samples, in the second - the method of one-way analysis of variance. For two related samples, a paired t-test is used. If we are talking about non-metric data from a single sample, the researcher can use frequency distribution tests, chi-square, Kolmogorov-Smirnov (K~S) test, series test and binomial test. For two independent samples with non-metric data, you can resort to the following methods of analysis: chi-square, Mann-Whitney, medians, K-S, one-way analysis of variance Kruskal-Wallis (ANOVA). In contrast, if there are two or more related samples, the sign, McNemar, and Wilcoxon tests should be used.
Multivariate statistical methods are aimed at identifying existing patterns: interdependence of variables, relationship or sequence of events, inter-object similarity.
Quite conventionally, we can distinguish five standard types of patterns, the study of which is of significant interest: association, sequence, classification, clustering and forecasting
An association occurs when several events are related to each other. For example, a study conducted in a supermarket may show that 65% of those who buy corn chips also buy Coca-Cola, and if there is a discount for such a set, they buy Coke in 85% of cases. Having information about such an association, it is easy for managers to assess how effective the discount provided is.
If there is a chain of events related in time, then we talk about a sequence. For example, after buying a house, in 45% of cases, a new kitchen stove is purchased within a month, and within two weeks, 60% of new residents acquire a refrigerator.
With the help of classification, signs are identified that characterize the group to which a particular object belongs. This is done by analyzing already classified objects and formulating some set of rules.
Clustering differs from classification in that the groups themselves are not predefined. Using clustering, various homogeneous groups of data are identified.
The basis for all kinds of forecasting systems is historical information stored in the form of time series. If it is possible to construct patterns that adequately reflect the dynamics of the behavior of target indicators, there is a possibility that with their help it is possible to predict the behavior of the system in the future.
Multivariate statistical methods can be divided into relationship analysis methods and classification analysis (Fig. 2.5).
Fig. 2.5 – Classification of multivariate statistical methods
Statistical Research (SI) allows you to get an idea of a particular phenomenon, study its size, level, and identify patterns. The subject of SI can be population health, organization medical care, factors external environment, affecting health, etc.
When conducting SI, they can be used 2 methodological approaches:
1) studying the intensity of the phenomenon in the environment, the prevalence of the phenomenon, identifying trends in the health of the population - carried out on general populations or sufficiently large in number sample populations, allowing to obtain intensive indicators and reasonably transfer the obtained data to the entire population
2) conducting strictly planned studies to study individual factors without identifying the intensity of the phenomenon in the environment - carried out, as a rule, on small populations in order to identify new factors, study unknown or little-known cause-and-effect relationships
Stages of statistical research:
Stage 1. Drawing up a research plan and program– is preparatory, during which the purpose and objectives of the research are determined, a research plan and program is drawn up, a program for summarizing statistical material is developed, and organizational issues are resolved.
A) the purpose and objectives of the study must be clearly formulated; the goal determines the main direction of the research and, as a rule, is not only theoretical, but also practical in nature, it is formulated clearly, clearly, unambiguously; To reveal the set goal, research objectives are determined.
B) it is necessary to study literature on this topic.
B) needs to be developed Organizational plan – provides for the determination of 1) place (administrative and territorial boundaries of observation), 2) time (specific terms of observation, development and analysis of material) and 3) subject of research (organizers, performers, methodological and organizational management, sources of research funding).
D) development Research plan – includes the definition:
– object of study (statistical population);
– volume of research (continuous, non-continuous);
– types (current, one-time);
– methods of collecting statistical information.
D) it is necessary to compose Research (observation) program – includes:
– definition of the observation unit;
– list of questions (accounting characteristics) to be registered in relation to each observation unit
– development of an individual accounting (registration) form with a list of questions and characteristics to be taken into account;
– development of table layouts, into which the research results are then entered.
A separate form is filled out for each observation unit; it contains the passport part, clearly formulated program questions posed in a certain sequence and the date of filling out the document. Medical registration forms used in the practice of treatment and preventive institutions can be used as registration forms.
Sources for obtaining information can be other medical documents (medical histories, and individual outpatient records, child development histories, birth histories), reporting forms from medical institutions, etc.
To ensure the possibility of statistical development of data from these documents, information is copied onto specially designed accounting forms, the content of which is determined in each individual case in accordance with the objectives of the study.
Currently, in connection with machine processing of observation results using a computer, program questions can be formalized , When questions in an accounting document are presented in the form of an alternative (yes, no) , Or ready-made answers are offered, from which a specific answer must be selected.
E) it is necessary to draw up a program for summarizing the obtained data, which includes establishing grouping principles and identifying grouping characteristics , Determining combinations of these characteristics, drawing up layouts of statistical tables.
Stage 2. Collection of material (statistical observation)– – consists of registration individual cases the phenomenon being studied and the accounting characteristics characterizing them in the registration forms. Before and during this work, the surveillance performers are instructed (oral or written) and provided with registration forms.
Statistical observation can be:
A ) by time:
1) Current– the phenomenon is studied for a specific period of time (week, quarter , Year, etc.) by daily recording the phenomenon as each case occurs (counting the number of births , Dead, sick , Discharged from hospital). This takes into account rapidly changing phenomena.
2) One-time– statistical data are collected at a certain (critical) point in time (population census, study physical development children, preventive examinations of the population). A one-time registration reflects the state of the phenomenon at the time of study and is used to study slowly changing phenomena.
The choice of the type of observation over time is determined by the purpose and objectives of the study (characteristics of hospitalized patients can be obtained as a result of the current registration of those leaving the hospital - current observation or by a one-day census of patients in the hospital - one-time observation).
B) depending on the completeness of coverage of the phenomenon being studied:
1) Solid– all observation units included in the population are studied, i.e. the general population. They are carried out in order to establish the absolute size of the phenomenon (total population, total number of births or deaths). It also applies in cases where information is necessary for operational work(accounting for infectious diseases, doctors’ workload, etc.)
2) Not continuous– only part of the general population is studied, divided into several types:
1. Monographic method– gives detailed description individual units of the totality that are characteristic in some respect and a deep, comprehensive description of objects.
2. Main Array Method– involves the study of those objects in which a significant majority of observation units are concentrated. The disadvantage of this method is that a part of the population remains uncovered by the study, although small in size, but which may differ significantly from the main array.
3. Questionnaire method is the collection of statistical data using specially designed questionnaires addressed to a specific circle of people. This study is based on the principle of voluntariness, therefore the return of questionnaires is often incomplete. Often the answers to the questions posed bear the imprint of subjectivity and randomness. This method is used to obtain an approximate characteristic of the phenomenon being studied.
4. Sampling method- the most common method, comes down to the study of some specially selected part of observation units to characterize the entire population. The advantage of this method is that it produces results with a high degree of reliability, as well as a significantly lower cost. The study involved fewer performers , In addition, it requires less time. IN medical statistics the role and place of the sampling method are especially great, since medical workers They usually deal only with part of the phenomenon being studied (they study a group of patients with a particular disease, analyze the work of individual departments).
C) by the method of obtaining information during the process and the nature of its implementation
1. Direct observation(clinical examination of patients , Conducting laboratory , Instrumental Research , Anthropometric measurements, etc.)
2. Sociological methods: interview method (face-to-face survey), questionnaire (correspondence survey - anonymous or non-anonymous), etc.;
3. Documentary research(copying information from medical records and reports, information from official statistics of institutions and organizations.)
Stage 3. Material development, statistical grouping and summary– begins with checking and clarifying the number of observations , Completeness and correctness of the information received , Identifying and eliminating errors, duplicate records, etc.
For proper development of the material, it is used Encryption of primary accounting documents, That is, the designation of each feature and its group with a sign - alphabetic or digital. Encryption is a technique , Facilitates and accelerates material development , Increasing quality and precision of development. Ciphers - symbols - are generated arbitrarily. When encoding diagnoses, it is recommended to use international nomenclature and classification of diseases; when encoding professions - with a dictionary of professions.
The advantage of encryption is that, if necessary, after completing the main development, you can return to the development material in order to clarify new connections and dependencies. Encrypted accounting material makes this easier and faster , Than unencrypted. After verification, the characteristics are grouped.
Grouping – division of the totality of data being studied into homogeneous ones , Typical groups based on the most significant characteristics. Grouping can be carried out according to qualitative and quantitative criteria. The choice of grouping characteristic depends on the nature of the population being studied and the objectives of the study.
A) Typological grouping produced according to qualitative (descriptive, attributive) characteristics (gender , Profession, disease groups)
B) Variational grouping(by quantitative characteristics) is carried out on the basis of the numerical dimensions of the characteristic (age , Duration of the disease, duration of treatment, etc.). Quantitative grouping requires solving the issue of the size of the grouping interval: the interval can be equal, and in some cases it can be unequal, even including so-called open groups (when grouping by age, open groups can be defined: up to 1 year, 50 years and older).
When determining the number of groups, they proceed from the purpose and objectives of the study. It is necessary that groups can reveal the patterns of the phenomenon being studied. Big number groups can lead to excessive fragmentation of the material and unnecessary detailing. A small number of groups leads to a blurring of characteristic features.
Having finished grouping the material, proceed to Summary– generalization of individual cases , Obtained as a result of statistical research, into certain groups, counting them and entering them into table layouts.
A summary of statistical material is carried out using statistical tables. Table , Not filled with numbers , Called Layout.
Statistical tables can be lists , Chronological, territorial.
The table has a subject and a predicate. The statistical subject is usually placed along horizontal lines on the left side of the table and reflects the main, main feature. The statistical predicate is placed from left to right along vertical columns and reflects additional accounting characteristics.
Statistical tables are divided into:
A) Simple– presents the numerical distribution of material according to one characteristic , Its components. A simple table usually contains a simple list or summary of the entire phenomenon being studied.
B) Group– a combination of two characteristics is presented in connection with each other
IN) Combination– the distribution of material is given according to three or more interrelated characteristics
When compiling tables, certain requirements must be met:
– each table must have a title reflecting its contents;
– inside the table, all columns must also have clear, short names;
– when filling out the table, all cells of the table must contain the corresponding numerical data. Cells in the table that are left blank due to the absence of this combination are crossed out (“-”), and if there is no information in the cell, “n.s.” or "…";
– after filling out the table, the vertical columns and horizontal rows are summed up in the bottom horizontal row and in the last vertical column on the right.
– tables must have a single sequential numbering.
In studies with a small number of observations, summaries are performed manually. All accounting documents are divided into groups in accordance with the attribute code. Next, the data is calculated and recorded in the appropriate cell of the table. Currently, computers are widely used in sorting and summarizing material. . Which allow not only to sort the material according to the characteristics being studied , But perform calculations of indicators.
Stage 4. Statistical analysis of the phenomenon under study, formulation of conclusions– a critical stage of the study, at which the calculation of statistical indicators (frequency , Structures , Average sizes of the phenomenon being studied), their graphic representation is given , Dynamics is being studied , Trends, connections between phenomena are established . Forecasts are made, etc. Analysis involves interpreting the data obtained and assessing the reliability of the research results. Finally, conclusions are drawn.
Stage 5. Literary processing and presentation of the results obtained– is final and involves finalization of the results of the statistical study. The results can be presented in the form of an article, report, report , Dissertations, etc. For each type of registration there are certain requirements , Which must be observed during literary processing of the results of statistical research.
The results of medical and statistical research are introduced into healthcare practice. Possible various options use of research results: familiarization with the results to a wide audience of medical and scientific workers; preparation of instructional and methodological documents; preparation of rationalization proposals and others
Upon completion of the statistical study, recommendations and management decisions are developed, the research results are implemented into practice, and effectiveness is assessed.
In conducting statistical research the most important element is to adhere to a strict sequence in the implementation of these stages.
To get an idea of a particular phenomenon and draw conclusions, it is necessary to conduct a statistical study. The subject of statistical research in health care and medicine can be the health of the population, the organization of medical care, various sections of the activities of medical institutions, and environmental factors that influence the state of health.
The methodological sequence of performing a statistical study consists of certain stages.
Stage 1. Drawing up a research plan and program.
Stage 2. Collection of material (statistical observation).
Stage 3. Material development, statistical grouping and summary
Stage 4. Statistical analysis of the phenomenon under study, formulation of conclusions.
Stage 5. Literary processing and presentation of the results obtained.
Upon completion of the statistical study, recommendations and management decisions are developed, the research results are implemented into practice, and effectiveness is assessed.
In conducting a statistical study, the most important element is adherence to a strict sequence in the implementation of these stages.
First stage statistical research - drawing up a plan and program - is preparatory, at which the purpose and objectives of the study are determined, a research plan and program is drawn up, a program for summarizing statistical material is developed, and organizational issues are resolved.
When starting a statistical study, you should accurately and clearly formulate the purpose and objectives of the study and study the literature on this topic.
The goal determines the main direction of the research and, as a rule, is not only theoretical, but also practical in nature. The goal is formulated clearly, clearly, unambiguously.
To reveal the set goal, research objectives are determined.
An important point The preparatory stage is the development of an organizational plan. The organizational plan of the study provides for the determination of the place (administrative and territorial boundaries of observation), time (specific terms of observation, development and analysis of material) and the subject of the study (organizers, performers, methodological and organizational management, sources of funding for the study).
Pl A n research d ov A nia includes:
Definition of the object of study (statistical population);
Scope of research (continuous, non-continuous);
Types (current, one-time);
Methods of collecting statistical information. Research program includes:
Definition of the unit of observation;
List of questions (accounting characteristics) to be registered in relation to each observation unit*
Development of an individual accounting (registration) form with a list of questions and characteristics to be taken into account;
Development of table layouts, into which the research results are then entered.
A separate form is filled out for each observation unit; it contains the passport part, clearly formulated program questions posed in a certain sequence and the date of filling out the document.
Medical registration forms used in the practice of medical treatment institutions can be used as registration forms.
Sources for obtaining information can be other medical documents (medical histories, and individual outpatient records, child development histories, birth histories), reporting forms from medical institutions, etc.
To ensure the possibility of statistical development of data from these documents, information is copied onto specially designed accounting forms, the content of which is determined in each individual case in accordance with the objectives of the study.
Currently, in connection with machine processing of observation results using a computer, program questions can be formalized , when questions in an accounting document are presented in the form of an alternative (yes, no) , or ready-made answers are offered, from which a specific answer must be selected.
At the first stage of statistical research, along with the observation program, a program* is compiled for summarizing the data obtained, which includes establishing the principles of grouping, identifying grouping characteristics , determination of combinations of these characteristics, drawing up layouts of statistical tables.
Second phase- collection of statistical material (statistical observation) - consists of registering individual cases of the phenomenon being studied and the accounting characteristics characterizing them on registration forms. Before and during this work, the surveillance performers are instructed (oral or written) and provided with registration forms.
In terms of time, statistical observation can be current or one-time.
At current observation Yu Denia the phenomenon is studied for a specific period of time (week, quarter , year, etc.) by daily recording the phenomenon as each case occurs. An example of current observation is the recording of the number of births , dead, sick , discharged from the hospital, etc. This takes into account rapidly changing phenomena.
At one-time observation Yu Denia statistical data is collected at a certain (critical) point in time. One-time observations include: population census, study of the physical development of children, accounting of hospital beds at the end of the year, certification of medical institutions, etc. This type also includes preventive examinations of the population. A one-time registration reflects the state of the phenomenon at the time of study. This type of observation is used to study slowly changing phenomena.
The choice of type of observation over time is determined by the purpose and objectives of the study. For example, characteristics of hospitalized patients can be obtained as a result of the ongoing registration of those leaving the hospital (ongoing surveillance) or from a one-day census of patients in the hospital (one-time observation).
Depending on the completeness of coverage of the phenomenon being studied, a distinction is made between continuous and non-continuous research.
At completely The study examines all units of observation included in the population, i.e. general population. A comprehensive study is carried out to establish the absolute size of the phenomenon, for example, the total population, the total number of births or deaths, total number sick with one or another disease, etc. The continuous method is also used in cases where information is necessary for operational work (taking into account infectious diseases, doctors’ workload, etc.)
At not continuous The study examines only a portion of the population. It is divided into several types: questionnaire, monographic, main array, selective. The most common in medical research is a sampling method.
Monographic method- gives a detailed description of individual units of the population that are characteristic in some respect and a deep, comprehensive description of objects.
Main Array Method- involves the study of those objects in which a significant majority of observation units are concentrated. The disadvantage of this method is that a part of the population remains uncovered by the study, although small in size, but which may differ significantly from the main array.
Questionnaire method is the collection of statistical data using specially designed questionnaires addressed to a specific circle of people. This study is based on the principle of voluntariness, therefore the return of questionnaires is often incomplete. Often the answers to the questions posed bear the imprint of subjectivity and randomness. This method is used to obtain an approximate characteristic of the phenomenon being studied.
Sampling method- comes down to the study of some specially selected part of observation units to characterize the entire population. The advantage of this method is that it produces results with a high degree of reliability, as well as a significantly lower cost. The study involved fewer performers , In addition, it requires less time.
In medical statistics, the role and place of the sampling method is especially great, since medical workers usually deal only with part of the phenomenon being studied: they study a group of patients with a particular disease, analyze the work of individual departments and medical institutions , evaluate the quality of certain events, etc.
According to the method of obtaining information during statistical observation and the nature of its implementation, several types are distinguished:
1) direct observation(clinical examination of patients , conducting laboratory , instrumental studies , anthropometric measurements, etc.)
2) sociological methods : interview method (face-to-face survey), questionnaire (correspondence survey - anonymous or non-anonymous), etc.;
3) documentary research A tion(copying information from medical records and reports, information from official statistics of institutions and organizations.)
Third stage- grouping and summary of material - begins with checking and clarifying the number of observations , completeness and correctness of the information received , identifying and eliminating errors, duplicate records, etc.
For the correct development of the material, encryption of primary accounting documents is used , those. designation of each characteristic and its group with a symbol - alphabetic or digital. Encryption is a technique , facilitating and accelerating material development , increasing the quality and accuracy of development. Ciphers - symbols - are generated arbitrarily. When encoding diagnoses, it is recommended to use the international nomenclature and classification of diseases; when encrypting professions - with a dictionary of professions.
The advantage of encryption is that, if necessary, after completing the main development, you can return to the development material in order to clarify new connections and dependencies. Encrypted accounting material makes this easier and faster , than unencrypted. After verification, the characteristics are grouped.
Grouping- division of the totality of the studied data into homogeneous ones , typical groups according to the most essential characteristics. Grouping can be carried out according to qualitative and quantitative criteria. The choice of grouping characteristic depends on the nature of the population being studied and the objectives of the study.
Typological grouping is made according to qualitative (descriptive, attributive) characteristics, for example, by gender , profession, disease groups, severity of the disease, postoperative complications, etc.
Grouping by quantitative (variational) characteristics is carried out on the basis of the numerical dimensions of the characteristic , For example , by age , duration of the disease, duration of treatment, etc. Quantitative grouping requires solving the issue of the size of the grouping interval: the interval can be equal, but in some cases it can be unequal, and even include so-called open groups.
For example , When grouped by age, open groups can be defined: up to 1 year . 50 years and older.
When determining the number of groups, they proceed from the purpose and objectives of the study. It is necessary that groups can reveal the patterns of the phenomenon being studied. A large number of groups can lead to excessive fragmentation of the material and unnecessary detailing. A small number of groups leads to a blurring of characteristic features.
Having finished grouping the material, proceed to the summary.
WITH vodka- generalization of individual cases , obtained as a result of statistical research, into certain groups, counting them and entering them into table layouts.
A summary of statistical material is carried out using statistical tables. Table , not filled with numbers , called a layout.
Statistical tables can be lists , chronological, territorial.
The table has a subject and a predicate. The statistical subject is usually placed along horizontal lines on the left side of the table and reflects the main, main feature. The statistical predicate is placed from left to right along vertical columns and reflects additional accounting characteristics.
Statistical tables are divided into simple , group and combinational.
IN simple tables presents the numerical distribution of material according to one characteristic , its components (Table 1). A simple table usually contains a simple list or summary of the entire phenomenon being studied.
Table 1
Distribution of deaths in hospital N. by age
IN group tables a combination of two characteristics is presented in connection with each other (Table 2).
table 2
Distribution of deaths in hospital N. by gender and age
IN combine A qi O these tables the distribution of material according to three or more interrelated characteristics is given (Table 3).
Table 3
Distribution of deaths in N. hospital various diseases by age and gender
| Diagnosis of the underlying disease | Age | ||||||||||||
| 0-14 | 15-19 | 20-39 | 40-59 | 60 and > | Total | ||||||||
| m | and | m | and | m | and | m | and | m | and | m | and | m+f | |
| Diseases of the circulatory system. | - | - | - | - | |||||||||
| Injuries and poisoning | - | - | - | ||||||||||
| Malignancy neoplasms. | - | - | - | - | - | - | |||||||
| Others. | - | - | - | - | |||||||||
| Everyone got sick. | - | - |
When compiling tables, certain requirements must be met:
Each table should have a title that reflects its contents;
Inside the table, all columns should also have clear, short titles;
When filling out a table, all cells of the table must contain the appropriate numeric data. Cells in the table that are left blank due to the absence of this combination are crossed out (“-”), and if there is no information in the cell, “n.s.” is entered. or "...";
After filling out the table, the vertical columns and horizontal rows are summed up in the bottom horizontal row and the last vertical column on the right.
Tables must have a single sequential numbering.
In studies with a small number of observations, summaries are performed manually. All accounting documents are divided into groups in accordance with the attribute code. Next, the data is calculated and recorded in the appropriate cell of the table.
Currently, computers are widely used in sorting and summarizing material. . which allow not only to sort the material according to the characteristics being studied , but perform calculations of indicators.
Fourth stage- statistical analysis is a critical stage of the study. At this stage, statistical indicators are calculated (frequency , structures , average size of the phenomenon being studied), their graphic representation is given , dynamics are being studied , trends, connections between phenomena are established . forecasts are given, etc. Analysis involves interpreting the data obtained and assessing the reliability of the research results. Finally, conclusions are drawn.
Fifth stage- literary treatment is final. It involves the finalization of the results of a statistical study. The results can be presented in the form of an article, report, report , dissertations, etc. For each type of design there are certain requirements , which must be observed when processing the results of statistical research in literature.
The results of medical and statistical research are introduced into healthcare practice. There are various options for using the research results: familiarization with the results to a wide audience of medical and scientific workers; preparation of instructional and methodological documents; preparation of rationalization proposals and others.
A quantitative description of socio-economic processes in direct connection with their qualitative essence in the system of social production is impossible without in-depth statistical research. Usage in various ways and techniques of statistical methodology presupposes the presence of comprehensive and reliable information about the object being studied. The study of mass social phenomena includes the stages of collecting statistical information and its primary processing, information and grouping of observation results into certain aggregates, generalization and analysis of the received materials.
At the first stage of statistical research, primary statistical data, or initial statistical information, is formed, which is the foundation of the future statistical building. For a building to be durable, its foundation must be sound and of high quality. If an error is made during the collection of primary statistical data or the material turns out to be of poor quality, this will affect the correctness and reliability of both theoretical and practical conclusions. Therefore, statistical observation from the initial to the final stage - obtaining final materials - must be carefully thought out and clearly organized.
Statistical observation provides the source material for generalization, the beginning of which is a summary. If during statistical observation about each of its units information is received that characterizes it from many aspects, then these summaries characterize the entire statistical totality and its individual parts. At this stage, the population is divided according to signs of difference and united according to signs of similarity, and total indicators are calculated for groups and as a whole. Using the grouping method, the phenomena under study are divided into the most important types, characteristic groups and subgroups according to essential characteristics. With the help of groupings, populations that are qualitatively homogeneous in significant respects are limited, which is a prerequisite for the definition and application of generalizing indicators.
On final stage analysis, using general indicators, relative and average values are calculated, a summary assessment of the variation of characteristics is given, the dynamics of phenomena are characterized, indices and balance sheets are used. Indicators characterizing the closeness of connections in changes in characteristics are calculated. For the purpose of the most rational and visual presentation of digital material, it is presented in the form of tables and graphs.
Concept of statistical observation
Stat. The research consists of 3 main stages:
1. Stat. observation
2. Primary processing, summary and grouping of observation results
3. Analysis of the obtained summary results
The observation process includes the following. stages:
1. Preparation of observation
2. Conducting mass data collection
3. Data preparation and processing for automated processing
4. Development of proposals for improving hundredth observation
It should be noted that the further results of analysis and quality depend on the completeness and quality of the material collected during the observation process.
15. Methodological issues of organizing statistics. observations.
Stat. observation should begin with a precise formulation of its goals and specific tasks. The following are defined:
Object and unit of observation
Program is being developed
Select the type and method of observation
Under the object stat. observation is understood as something. statistical totality in which the studied social ecology takes place. phenomena and processes
(N: sov-t – p/p
Persons living on def. territories
Students, training in universities)
Observation unit is called a component of objects of observation that is a carrier of signs subject to registration (department no., subdivision, department of students, people)
It is necessary to distinguish observation units from reporting units under the cat. understood by subjects who provide information about the unit of observation (often these concepts coincide)
An observation program is a list of issues on which information is collected or a list of signs and indicators to be registered.
The observation program is drawn up in the form of a statistical form, form, questionnaire, questionnaire or census form, etc., where primary research is entered.
The key issue when organizing observation is phenomena. the question of the place and time of its conduct depends mainly on the purpose of the study.
Choosing the location of the observation def. tasks and goals of the study (for which group they want to obtain data, they study it)
The choice of time is included in the definition of the observation period and the critical moment of observation.
Observation period – the time during which registration must be carried out.
The critical observation date is the date as of which information is reported.
The critical moment is the point in time at which the observed facts are recorded.
Their differences are explained and often during the observation period. If it lasts long enough, during this time certain changes in the totality may occur, cat. needs to be reflected on others. Therefore, the results of observations. fixed as of the critical moment. The changes that have taken place are not learned in the future.
A critical moment is like a snapshot of a population (or a study of a population)
As a rule, the critical moment is tied to the start date of the work.
Forms, types, methods of stat. observations
Forms.
1. Stat. reporting is an organizational form in which observation units provide information about their activities in the form of forms, regulatory apparatus.
The peculiarity of reporting is that it must be justified, enforceable and legally confirmed by the signature of the manager or responsible person.
2. Specially organized observation is the most striking and simple example of this form of observation of phenomena. census. The census is usually carried out at regular intervals, simultaneously throughout the entire study area at the same time.
Russian statistical bodies conduct population censuses individual species subdivisions and organizations, material resources, perennial plantings, NZ construction sites, etc.
4. Register form of observation - based on maintaining a statistical register. In the register each unit of observation is characterized by a number of indicators. In domestic statistical practice, the most widespread are the US-I registers and the sub-registers.
Population registration is carried out by the Civil Registry Office
Registration - USRPO led.org. statistics.
Kinds.
can be divided into groups according to the following. signs:
a) according to the time of registration
b) by coverage of units of society
By time reg. they are:
Current (continuous)
Intermittent (periodic and one-time)
At current obs. changes in phenomena and processes are recorded as they occur (registration of birth, death, marriage, divorce, etc.)
Periodic obs. carried out through def. time intervals (N population census every 10 years)
One time obs. carried out either not regularly, or only once (referendum)
By coverage units. Sov-ti stat-e observ. there are:
Solid
Not continuous
Continuous observation is a survey of all units of society
Continuous observation assumes that only part of the research is subject to observation.
There are several types of non-continuous observation:
Basic method array
Selective (on your own)
Monographic
This method is characterized by the fact that, as a rule, the most creatures are selected, usually the largest units. sov-ti in the cat. center means. part of all the signs.
With monographic observation, careful an. are subject to dept. units study the owl or maybe or typical for a given Soviet unit. or presenting new varieties of phenomena.
Multi-observation carried out with the aim of identifying or emerging trends in the development of this phenomenon.
Methods
Direct observation
Documentary observation
Directly called such obs. with cat The registrars themselves, by immediately measuring, counting, restraining the fact that is subject to registration, and on this basis make an entry in the form.
Documentary method of observation. based on the use of various documents as sources of information, usually accounting records (i.e. statistical reporting)
A survey is a method of persuasion with a cat. the necessary information will be obtained from the words of the respondent (i.e., the person being interviewed) (oral, correspondent, questionnaire, personal, etc.)
The result of the first stage of statistical research - statistical observation - is information characterizing each unit of the statistical population. However, the ability to reflect patterns and trends in the dynamics of the phenomena being studied using even the most full characteristics individual facts are limited. Such data is obtained only as a result of statistical summaries. A summary is the arrangement, systematization and generalization of statistical data obtained during statistical observation. Only proper processing of statistical material allows us to identify the essence of socio-economic phenomena, character traits and essential features of individual types, to discover patterns and trends in their development. There are simple and group reports, or reports in the narrow and broad sense. A simple summary is the calculation of the overall results in groups and subgroups and the presentation of this material in tables. As a result of a simple summary of statistical data, it is possible to determine the number of enterprises, the total number of personnel, and the volume of products produced in monetary terms. These overall results are primarily for informational purposes. They provide a generalized characteristic of the population in the form of absolute values.
Group summary, or summary in a broad sense, is a complex process of multilateral processing of primary statistical data, i.e. data obtained as a result of observation. It includes grouping statistical data, developing a system of indicators to characterize groups, calculating group and overall results, and calculating generalizing indicators. The task of the statistical summary as the second stage of statistical research is to obtain general indicators for information, reference and analytical purposes. The summary of mass statistical data is carried out according to a pre-developed program and plan. During the program development process, the subject and predicate of the summary are determined. The subject is the object of study, divided into groups and subgroups. Predicate - indicators that characterize the subject of the summary. The summary program is determined by the objectives of the statistical study.
The statistical summary is carried out according to a pre-drawn plan. In terms of summaries, questions are addressed about how to carry out the work of summarizing information - manually or mechanically, and about the sequence of individual summation operations. The deadlines for completing each stage and the summary as a whole are established, as well as methods for presenting the results of the summary. These can be distribution series, statistical tables and statistical graphs.
