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Data Collection & Its Methods

Last Updated : 17 Jan, 2024
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What is Data Collection?

Data Collection is the process of collecting information from relevant sources in order to find a solution to the given statistical enquiry. Collection of Data is the first and foremost step in a statistical investigation. 

Here, statistical enquiry means an investigation made by any agency on a topic in which the investigator collects the relevant quantitative information. In simple terms, a statistical enquiry is the search of truth by using statistical methods of collection, compiling, analysis, interpretation, etc. The basic problem for any statistical enquiry is the collection of facts and figures related to this specific phenomenon that is being studied. Therefore, the basic purpose of data collection is collecting evidence to reach a sound and clear solution to a problem.


Important Terms related to Data Collection:

1. Investigator: An investigator is a person who conducts the statistical enquiry.

2. Enumerators: In order to collect information for statistical enquiry, an investigator needs the help of some people. These people are known as enumerators.

3. Respondents: A respondent is a person from whom the statistical information required for the enquiry is collected.

4. Survey: It is a method of collecting information from individuals. The basic purpose of a survey is to collect data to describe different characteristics such as usefulness, quality, price, kindness, etc. It involves asking questions about a product or service from a large number of people.


The table below shows the production of rice in India.

Production of Rice in India

The above table contains the production of rice in India in different years. It can be seen that these values vary from one year to another. Therefore, they are known as variable. A variable is a quantity or attribute, the value of which varies from one investigation to another. In general, the variables are represented by letters such as X, Y, or Z. In the above example, years are represented by variable X, and the production of rice is represented by variable Y. The values of variable X and variable Y are data from which an investigator and enumerator collect information regarding the trends of rice production in India. 

Thus, Data is a tool that helps an investigator in understanding the problem by providing him with the information required. Data can be classified into two types; viz., Primary Data and Secondary Data. Primary Data is the data collected by the investigator from primary sources for the first time from scratch. However, Secondary Data is the data already in existence that has been previously collected by someone else for other purposes. It does not include any real-time data as the research has already been done on that information.

Methods of Collecting Data

Methods of Collecting Data

There are two different methods of collecting data: Primary Data Collection and Secondary Data Collection. 

A. Methods of Collecting Primary Data:

There are a number of methods of collecting primary data, Some of the common methods are as follows:

1. Direct Personal Investigation: As the name suggests, the method of direct personal investigation involves collecting data personally from the source of origin. In simple words, the investigator makes direct contact with the person from whom he/she wants to obtain information. This method can attain success only when the investigator collecting data is efficient, diligent, tolerant and impartial. For example, direct contact with the household women to obtain information about their daily routine and schedule.

2. Indirect Oral Investigation: In this method of collecting primary data, the investigator does not make direct contact with the person from whom he/she needs information, instead they collect the data orally from some other person who has the necessary required information. For example, collecting data of employees from their superiors or managers.

3. Information from Local Sources or Correspondents: In this method, for the collection of data, the investigator appoints correspondents or local persons at various places, which are then furnished by them to the investigator. With the help of correspondents and local persons, the investigators can cover a wide area.

4. Information through Questionnaires and Schedules: In this method of collecting primary data, the investigator, while keeping in mind the motive of the study, prepares a questionnaire. The investigator can collect data through the questionnaire in two ways:

  • Mailing Method: This method involves mailing the questionnaires to the informants for the collection of data. The investigator attaches a letter with the questionnaire in the mail to define the purpose of the study or research. The investigator also assures the informants that their information would be kept secret, and then the informants note the answers to the questionnaire and return the completed file. 
  • Enumerator’s Method: This method involves the preparation of a questionnaire according to the purpose of the study or research. However, in this case, the enumerator reaches out to the informants himself with the prepared questionnaire. Enumerators are not the investigators themselves; they are the people who help the investigator in the collection of data.

B. Methods of Collecting Secondary Data

Secondary data can be collected through different published and unpublished sources. Some of them are as follows:

1. Published Sources

  • Government Publications: Government publishes different documents which consists of different varieties of information or data published by the Ministries, Central and State Governments in India as their routine activity. As the government publishes these Statistics, they are fairly reliable to the investigator. Examples of Government publications on Statistics are the Annual Survey of Industries, Statistical Abstract of India, etc.
  • Semi-Government Publications: Different Semi-Government bodies also publish data related to health, education, deaths and births. These kinds of data are also reliable and used by different informants. Some examples of semi-government bodies are Metropolitan Councils, Municipalities, etc.
  • Publications of Trade Associations: Various big trade associations collect and publish data from their research and statistical divisions of different trading activities and their aspects. For example, data published by Sugar Mills Association regarding different sugar mills in India.
  • Journals and Papers: Different newspapers and magazines provide a variety of statistical data in their writings, which are used by different investigators for their studies.
  • International Publications: Different international organizations like IMF, UNO, ILO, World Bank, etc., publish a variety of statistical information which are used as secondary data.
  • Publications of Research Institutions: Research institutions and universities also publish their research activities and their findings, which are used by different investigators as secondary data. For example National Council of Applied Economics, the Indian Statistical Institute, etc.

2. Unpublished Sources

Another source of collecting secondary data is unpublished sources. The data in unpublished sources is collected by different government organizations and other organizations. These organizations usually collect data for their self-use and are not published anywhere. For example, research work done by professors, professionals, teachers and records maintained by business and private enterprises

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