After reading this article, you will learn what forms, types and methods of observation exist. We are talking about their allocation in the statistics. We propose to first consider the types of observation that are used in this branch of knowledge. The need to choose a data collection option in it is determined by the fact that there are several types of observation. They differ mainly in the way in which 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 appear, is commonly called current. It is carried out on the basis of primary documents containing the necessary information for a fairly complete characterization of the phenomenon.
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, we are talking about a one-time observation.
Discontinuous and continuous observation
Types of observation in statistics are distinguished taking into account the difference in information in terms of completeness of population coverage. Distinguish in connection with this discontinuous and continuous. The latter is called one that takes into account all units of the studied population, without exception. However, it is not always expedient and possible to organize it, 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 sphere of use. Therefore, it is necessary to carry out partial (non-continuous) observation. It takes into account only a part of the population units 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 non-continuous observation has the following advantages:
1) requires much less communication and labor costs compared to continuous, as the number of surveyed units decreases;
2) it is possible to collect data according to a wider program and in a shorter timeframe in order to comprehensively disclose within the given limits the features of the population of interest to us, to carry out its deep study;
3) non-continuous observation data is used to control materials obtained from continuous;
4) this kind should berepresentative (representative).
Selection of units for non-continuous observation
Discontinuous observation is deliberately oriented towards taking into account a specific part of the units, which makes it possible to obtain generalized stable characteristics of the population as a whole. In the practice of statistics, various types of observation methods are used. At the same time, the quality of a non-continuous one, of course, is inferior to the results obtained with a continuous one. However, in some cases only partial observation is possible.
The units to be studied are selected in such a way that, based on the data obtained from them, a correct idea of the phenomenon of interest as a whole is formed. Therefore, one of the main features of non-continuous observation is that the selection of population units is organized in the following ways:
- monographic;
- main array;
- selective;
- questionnaire.
Main array method
Selection of units of a certain population, which predominate according to the trait under study, involves the method of the main array. However, it is not so often used when a non-continuous view is used, and this method of observation does not ensure the selection of precisely those units that would represent the totality as a whole, all its parts. Selection using the main array is made when the most significant, largest populations are taken, which prevail according to the trait under study in their total mass.
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 sampling. In this option, the random nature of the selection guarantees the safety of the results obtained, prevents their bias.
Monographic description
Supplement the types of observation with a monographic description. It is a specific kind of observation in statistics. This is a detailed study of a single typical object that is interesting from the point of view of the population as a whole.
These are the main types of non-continuous observation.
Population and sample
The generalizing indicators of the population in the sampling method are set on the basis of some part of it (rather small - about 5-10%). At the same time, the set from which the selection of this part of the units is carried out is usually called the general set. The part of the units that was selected is called the sampling set (in other words, the sample). When using the sampling method, research is carried out with minimal costs of funds and labor and in a shorter time. This reduces registration errors and improves responsiveness.
Practical application of the sampling method
Describing the main types of observation, one cannot but dwell in more detail on the selective one, which is very popular. It is only possible when product quality control can only be carried out destructively. This species is common in departmental andstate statistics (study of 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.
A 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 sampling method
Examples of types of observation allow you to visually demonstrate their use. Here are some examples of sampling, and you will better understand its features. It is he who is most theoretically developed today from discontinuous ones, since he is based on the principle of random selection. Each unit in the population at random selection has the same probability of being included in the sample. In a lottery draw, for example, this principle applies because there is an equal chance of winning for all tickets. The draw also uses random selection. If out of 10,000 schoolchildren, 1,000 are selected for the purpose of studying their performance, then this can be done as follows: write the names of schoolchildren on separate sheets of paper and blindly pull out 1000.
Repeated and reselection
Random selection can be both non-repeated and repeated. In practice, non-repetitive is most often used, that is, the unit that has fallen into the sample is not returned back to the general population, which means that the number of the latter is constantly decreasing. Lottery draws follow this pattern. The selected unit, when re-selected, is returned back to the general population. Consequently, the number of the latter remains unchanged during the sampling process. If we turn to our example with schoolchildren, we can note the following: in this case, if a sheet with a surname falls into the number of randomly selected ones, it 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 survey or individuals, can influence. In other words, it is necessary that the principle of random selection be respected. However, in practice, its implementation is often difficult. There are areas of statistics in which expert selection methods predominate. 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 assessing the cost of living. In such cases, the rejection of the random selection method can significantly increase the accuracy. However, in this case, the objectivity of the study is lost, and sometimes various types of observation errors occur, since in this case everything depends on the qualifications of the expert.
Mechanical (systematic) selection
Mechanical (systematic) selection is often used in practice. For example, out of 10,000 schoolchildren, a thousand should 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 made (10000 divided by 1000). If the third student is in the top ten (you can choose him by drawing lots), in this case the 13th, 23rd, 33rd … 9993rd will be selected. 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 student). It should be noted that mechanical (systematic) selection is always non-repetitive. It should also be emphasized that the selected units under it are distributed evenly 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, now let's move on to studying the methods. The fact is that the varieties of observation can also be distinguished regardless of the ways and sources of obtaining primary information. From this point of view, a distinction is made between documentary observation, questioning and direct observation.
Direct is such an observation that is carried out by counting, measuring the values of some signs, by taking readings of instruments by the persons who carry it out (they are called registrars).
Due to the fact that other methods and types of statistical observation cannot be applied, quite often it is carried out using a survey on a specific list of questions. Answers are recorded in a special form. There are, depending on how they are received, correspondent and forwarding, as well as a method of self-registration. Let's briefly describe each of them.
Forwarding is carried out by a special person (forwarder, counter) orally. This person fills out a survey or form.
The correspondent method is organized by sending survey forms to a certain circle of persons prepared accordingly (they are called correspondents). These people, according to the agreement, must fill out the form, and then return it to the organization. The self-registration survey checks whether the forms have been completed correctly. As with the correspondent method, the questionnaires are filled in by the respondents themselves, however, the collection and distribution of them, as well as the control of the correctness of filling and instructions, are carried out by counters.
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: a 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 them.
Reporting is the main form of surveillance. With its help, state statistics authorities receive information from organizations and enterprises in the form of reporting documents signed by responsible persons.
Specially organized observation - the collection of information organized by the statistical authorities to study notphenomena covered by reporting or for a deeper study of reporting data, their clarification 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 observation of processes that take place for a long time, which have a certain beginning, development and end. The facts of the state of the units of the population are continuously fixed. In statistical practice, business registers and population registers are distinguished. The latter represent a regularly updated and named list of the country's inhabitants. The register of enterprises contains enterprises with various types of economic activity and the values of certain characteristics for each unit.
So, we have considered the forms, methods, types of statistical observation. Of course, we touched on them only briefly, but we noted the most important.
