After reading this article, you will learn 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 data collection option in it is determined by the fact that there are several types of observation. They differ among themselves mainly in the way facts are taken into account over time. From this point of view, the following types of observation are distinguished: systematic, periodic and one-time.
Systematic, periodic and one-time observation
Systematic observation, which is carried out continuously and as signs of a phenomenon of interest occur, is usually called current. It is based on containing the necessary information for a fairly complete description of the phenomenon of primary documents.
Periodic monitoring is carried out at regular intervals. An example is the census.
If the observation is carried out from time to time, there is no strict periodicity, or it is of a one-time nature, we are talking about a one-time observation.
Incomplete 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, continuous and continuous. The latter is called 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 product quality control. Continuous observation in this case leads to the fact that the mass of products of enterprises is excluded from the scope of use. Therefore, it is necessary to carry out partial (non-continuous) observation. It takes into account only part of the units of the aggregate 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 communication and labor costs are required compared to continuous, since the number of units being examined is reduced;
2) data can be collected according to a broader program and in a shorter time, in order to comprehensively reveal within the given limits the features of the aggregate of interest to us, to carry out a deep study of it;
3) discontinuous observation data is used to control materials obtained in continuous;
4) this species should be representative (representative).
Selection of units during non-continuous observation
A non-continuous observation is obviously oriented towards taking into account a specific part of units, which allows one to obtain generalizing stable characteristics of the population as a whole. In the practice of statistics, various types of observation method are used. Moreover, the quality of discontinuous, of course, is inferior to the results obtained with continuous. Nevertheless, in some cases only incomplete observation is possible.
The units that should be studied are selected in such a way that, based on the data obtained from them, to form a true idea of the interesting phenomenon as a whole. Therefore, one of the main features of observing an incomplete is that the selection of units of the population is organized in the following ways:
- monographic;
- the main array;
- selective;
- questionnaire.
Main Array Method
The selection of units of a certain population that prevail according to the trait being studied suggests the method of the main array. However, it is not so often used when a non-continuous view is used, and this observation method does not provide the selection of precisely those units that would represent the whole as a whole, all its parts. Selection with the help of the main array is carried out when the most significant, largest aggregates are taken, which prevail in the total mass according to the studied attribute.
Selective observation
In order to obtain a characteristic of the population as a whole in terms of its units, selective observation is used, which is based on the principles of the sample population. In this embodiment, the random nature of the selection guarantees the safety of the results obtained, 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 totality as a whole.
These are the main types of incomplete observation.
Population and sample
Summarizing indicators of the population in the selective method are established on the basis of some part of it (rather small - about 5-10%). In this case, the totality from which the selection of this part of the units is carried out is called the general. The part of units that was selected is called a sampling frame (otherwise, a sample). The study using the sampling method is carried out with minimal cost of funds and labor and in a shorter time. This reduces registration errors and improves responsiveness.
The application of the selective method in practice
Describing the main types of observation, one cannot help but dwell in more detail on the selective, which is very popular. It is only possible when product quality control can only be destructive. This type is widespread 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 conduct, the demand for goods from the population), etc.
The selective method is, in fact, a large group of methods that differ significantly from each other. As a rule, they are based on the principle of random selection from the general population.
Examples of using the selective method
Examples of types of observation allow you to clearly demonstrate their use. Here are a few examples of selective, and you better understand its features. It is he who is the most theoretically developed from discontinuous ones today, since he is based on the principle of random selection. Each unit of the population with random sampling has the same probability of falling into the sample. When drawing a lottery, for example, this principle is applied, since an equal chance of winning exists for all tickets. The draw also uses random selection. If one out of 10,000 schoolchildren is selected to study their academic performance, then this can be done as follows: write the names of schoolchildren on separate sheets and pull out 1000 blindly.
Repeatless and re-selection
Random and repeated can be random selection. In practice, non-repetitive is most often used, that is, the unit that fell into the sample does not return back to the general population, which means that the number of the latter decreases all the time. Lottery runs are held according to this scheme. The selected unit, when re-selected, is returned back to the population. Consequently, the number of the latter remains unchanged in the process of sampling. If we turn to our example with schoolchildren, we can note the following: in this case, if a leaflet with a surname fell into the number of those selected by chance, he would again come back and again could fall into the sample.
Expert selection methods
It is very important that no factors, such as the commission organizing the examination or persons, can influence. In other words, the principle of random selection must be respected. However, in practice, its implementation is often difficult. There are areas of statistics in which expert selection methods prevail. This situation develops due to various circumstances. For example, it takes place when selecting goods for calculating price indices or when forming the composition of “baskets” for assessing the cost of living. Significantly improve the accuracy in such cases, the rejection of the random selection method. However, in this case, the objectivity of the study is lost, and sometimes various types of observation errors occur, since everything in this case depends on the qualification of the expert.
Mechanical (systematic) selection
Often in practice, mechanical (systematic) selection is used. Suppose, out of 10 thousand students, a thousand need to be selected. In this case, they do this: all the guys are arranged in alphabetical order, and then every tenth of them is selected.
Since the interval in this case is 10, a 10% selection is carried out (10,000 divided by 1000). If the third student is in the top ten (you can choose him by lot), the 13th, 23rd, 33rd ... 9993th will be selected in this case. In a systematic selection, as we see, the general population is mechanically divided into a number of groups, and one unit is taken from each (in our example, one student). It should be noted that mechanical (systematic) selection is always unique. It should also be emphasized that the selected units with it are distributed evenly throughout the entire population.
Methods of observation in statistics
It is necessary to distinguish between the methods and types of statistical observation. We have just examined the latter; now we will move on 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, there are documentary observation, questioning and direct observation.
Direct - this is such an observation, which is carried out by counting, measuring the values of some signs, by taking readings of devices by persons who carry it out (they are called registrars).
Due to 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. In a special form answers are recorded. Distinguish, depending on how they are received, correspondent and expeditionary, as well as the method of self-registration. Let us briefly describe each of them.
Forwarding is carried out by a special person (freight forwarder, counter) orally. This person fills out an examination form or form.
The correspondent method is organized by sending survey forms to a specific circle of people prepared accordingly (they are called correspondents). These people, as agreed, must fill out the form, and then return it to the organization. When interviewing by self-registration, a check is made to see if the forms are filled out correctly. As with the correspondent method, the questionnaires are filled out by the respondents themselves, however, the collection and distribution of them, as well as the control of the correctness of the filling and briefing are carried out by the counters.
Observation forms in statistics
Considering the forms, methods, types of statistical observation, we did not talk only about forms. There are three of them: register, specially-organized monitoring and reporting. As you can see, the types and forms of statistical observation are not the same thing. You should understand the difference between the two.
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.
A specially organized observation is a collection of information that is organized by statistical bodies to study phenomena not covered by the reporting, or for a deeper study of the reported data, their refinement and verification. It is carried out in the form of various surveys and censuses.
We have described almost all the main methods, types and forms of statistical observation. Only the last form remains - registers. It takes place in the case of continuous monitoring of processes occurring for a long time, which have a definite beginning, development and end. The facts of the state of aggregate units are continuously recorded. In statistical practice, business registers and population registers are distinguished. The latter are a regularly updated and named list of residents of the country. The enterprise register contains enterprises with all kinds of economic activities and the values of certain attributes for each unit.
So, we examined the forms, methods, types of statistical observation. Of course, we touched on them only briefly, but the most important thing we noted.