Types of observation. Types and forms of statistical observation

After reading this article, you will find out what forms, types and methods of observation exist. We are talking about their allocation in statistics. We suggest first to consider the types of observation that are used in this branch of knowledge. The need to choose the option of data collection in it is determined by the fact that there are several types of observation. They differ among themselves mainly by the way in which facts are taken into account in time. From this point of view, the following types of observation are distinguished: systematic, periodic and one-time.

Systematic, periodic and one-time observation

The observation is systematic, which is carried out continuously and with the appearance of the signs of the phenomenon of interest, it is customary to call the current one. It is conducted on the basis of containing the necessary information for a fairly complete description of the phenomenon of primary documents.

Periodic observation is carried out at regular intervals. An example is the population census.

If the observation is carried out from time to time, there is no strict periodicity, or it has a one-time character, it is a question of a one-time observation.

Unstoppable and continuous observation

Types of observation in statistics are distinguished taking into account the difference in information in terms of completeness of coverage of the population. Distinguish in this regard discontinuous and continuous. The latter is called the one that takes into account all units of the studied population without exception. However, its organization is not always expedient and possible, especially when it comes to quality control of products. A continuous observation in this case leads to the fact that the mass of products of enterprises is excluded from the sphere of use. Therefore, it is necessary to carry out a partial (non-continuous) observation. It takes into account only a part of the units of the population and gives an idea of the phenomenon as a whole, its characteristic features.

Continuing to consider the forms, types and methods of observation, we note that incomplete observation has the following advantages:

1) much less expenditure of communication and labor is required compared to the continuous one, since the number of surveyed units is decreasing;

2) the data can be collected according to a broader program and in a shorter timeframe in order to comprehensively expose the features of the population of interest to us within specified limits, to carry out a deep study of it;

3) observational data of a non-continuous one are used for the control of materials obtained in solid state;

4) this species should be representative (representative).

Selection of units for close observation

The non-continuous observation is oriented deliberately to account for a particular part of the units, which makes it possible to obtain generalizing stable characteristics of the aggregate as a whole. In the practice of statistics, various types of observation methods are used . In this case, the quality of the non-continuous, of course, is inferior to the results obtained with the solid one. Nevertheless, in a number of cases only a non-continuous observation is possible.

Units that should be studied are selected in such a way that, based on the data obtained from them, make up a correct view of the phenomenon of interest as a whole. Therefore, one of the main features of observing the non-continuous is that the selection of units of the aggregate is organized in the following ways:

- monographic;

- the main array;

- selective;

- questionnaire.

Main array method

Selection of units of a certain aggregate, which prevail over the studied feature, assumes the method of the main array. However, it is not so often used when a discontinuous species is used, and this observation method does not ensure the selection of precisely those units that would represent the population as a whole, all its parts. Selection with the help of the main array is performed when the most significant, largest aggregates are taken, which predominate over the studied feature in the total mass.

Selective observation

In order to obtain a characterization of the population as a whole for a part of its units, selective observation is used, which is based on the principles of the sample population. In this variant, the random nature of the selection guarantees the safety of the results obtained, and prevents their tendentiousness.

Monographic Description

We supplement the types of observation with a monographic description. It is a specific type of observation in statistics. This is a detailed study of a single typical object, which is interesting from the point of view of the population as a whole.

These are the main types of discontinuous observation.

General population and sample

Generalizing indicators of the population in the sampling method are established on the basis of some of its part (rather small - about 5-10%). In this case, the collection from which this part of the units is selected is commonly called the general. The part of the units that was selected is called the sample set (otherwise it is a sample). The study using the sampling method is carried out with minimal outlays of resources and labor and in shorter terms. This reduces registration errors and improves responsiveness.

Application of sampling method in practice

Describing the main types of observation, it is impossible not to dwell more on selective, which is very popular. It is only possible when quality control of products can be carried out only destructive. This type is distributed in departmental and state statistics (studying the budget of families of employees, peasants, workers, as well as housing conditions). It is also popular in trade (the effectiveness of new forms of its management, the demand for goods on the part of the population), etc.

The selective method is, in fact, a large group of methods that differ significantly from one another. As a rule, they are based on the principle of random selection from the general population.

Examples of using the sampling method

Examples of types of observation allow us to clearly demonstrate their use. Here are some examples of selective, and you will better understand its features. The most theoretically developed today from the discontinuous is precisely it, because it is based on the principle of random selection. Each unit of the population in case of random selection has the same probability of getting into the sample. When carrying out lottery draws, for example, this principle is applied, since an equal opportunity of winning exists for all tickets. Random selection is also used for the draw. If out of 10 thousand students to select 1 thousand for the purpose of studying their academic performance, then it is possible to do this as follows: on separate sheets write the names of schoolchildren and pull out blindly 1000.

Non-repetitive and repeated selection

Both repetitive and repeated can be random selection. In practice, the most frequently used is a non-repetitive one, that is, a unit that is in the sample does not return back to the general population, and hence the number of the latter decreases all the time. The lottery draws according to this scheme. The selected unit returns to the population at the second selection. Consequently, the number of the latter remains unchanged during the sampling process. If we look at our example with schoolchildren, then we can note the following: in this case, if a leaf with a surname was included in the number of those selected accidentally, it would come back again and again could get into the sample.

Methods of selection by experts

It is very important that no factors, for example, the organizing committee or persons, can influence. In other words, it is necessary that the principle of random selection is observed. However, in practice, its implementation is often difficult. There are areas of statistics in which methods of selection by experts prevail. This situation is due to various circumstances. For example, it takes place when selecting goods for the calculation of price indices, or when forming the composition of "baskets" for realizing the cost of living. Significantly improve the accuracy can in such cases, the rejection of the random selection method. However, the objectivity of the research is lost, and sometimes there are different types of observation errors, because everything depends on the expert's qualification in this case.

Mechanical (systematic) selection

Often in practice, a mechanical (systematic) selection is used. Let's say that out of 10,000 schoolchildren, you need to select a thousand. In this case, they do this: all the children are placed in alphabetical order, and then every tenth of them is selected.

Since the interval in this case is 10, a 10% selection is made (10,000 divided by 1000). If in the first ten there was the third schoolboy (you can choose it by lot), the selected in this case will be the 13th, 23rd, 33rd ... 9993th. With systematic selection, as we see, the general population is divided mechanically into a number of groups, and one unit is taken from each (in our example, one schoolchild). It should be noted that mechanical (systematic) selection is always repetitive. It should also be emphasized that the selected units are distributed uniformly throughout the entire population.

Methods of observation in statistics

It is necessary to distinguish between methods and types of statistical observation. We have just considered the latter, we now turn to the study of methods. The fact is that the types of observation can also be distinguished independently of the ways and sources of obtaining primary information. From this point of view, documentary observation, questioning and direct observation are distinguished.

The immediate is an observation that is carried out by counting, measuring the values of certain characteristics, by taking readings of the instruments by persons who perform it (they are called registrars).

In view of the fact that it is impossible to apply other methods and types of statistical observation, quite often it is carried out using a survey on a specific list of issues. The special form fixes the answers. Distinguish, depending on how they are received, correspondent and expeditionary, and also a way of self-registration. We describe briefly each of them.

Expedition carried out by a special person (freight forwarder, counter) orally. This person fills out a form of examination or a form.

Correspondent way is organized by sending out survey forms to a certain circle of people, prepared accordingly (they are called correspondents). These people, according to the agreement, must fill out the form, and then return it to the organization. When polling by self-registration, it is checked whether the forms are filled in correctly. As with the correspondent method, questionnaires are filled in by the respondents themselves, but the counters collect and distribute them, as well as control the correctness of filling and instructing.

Forms of observation in statistics

Considering the forms, methods, types of statistical observation, we did not talk only about the forms. There are three of them: the register, specially-organized observation and reporting. As you can see, the types and forms of statistical observation are not the same. You should understand the difference between them.

Reporting is the main form of observation. With its help, state statistics bodies receive information from organizations and enterprises in the form of reporting documents signed by responsible persons.

Specially organized surveillance is the collection of information that is organized by statistical bodies to study phenomena not covered by reporting, or for a more in-depth study of reporting data, their clarification and verification. It is conducted in the form of various surveys and censuses.

We described almost all the main methods, types and forms of statistical observation. There was only the last form - registers. It takes place in the case of continuous monitoring of processes that have been going on for a long time, which have a certain beginning, development and end. The facts of the state of the units of the aggregate are continuously recorded. In statistical practice, business registers and registers of the population are distinguished. The latter are a regularly updated and named list of residents of the country. The register of enterprises contains enterprises with all kinds of economic activities and the values of certain characteristics for each unit.

So, we examined the forms, methods, types of statistical observation. Of course, we only touched upon them briefly, but the most important thing we noted.