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Chapter 2 Collection of Data 11th Commerce

Statistics for economics

Chapter 2 Collection of Data


Concept Collection of Data                                                                                                         

Collection of data is the first step in any statistical investigation. So, it is a very important function. Let us discuss this with the help of

Production of Food Grains in India (Million Tonnes)

As seen in Table the food grains production varies from year to year. As these values vary, they are called variable. A variable refers to quantity or attribute whose values varies from one investigation to another. The variables are generally represented by the letters X, Y or Z.

In Table the years are represented by variable X and the production of food grains by variable Y. These values of the variables X and Y are the ‘data’, from which we can obtain information about the trend of the production of food grains in India. ‘Data’ is a tool, which helps in understanding problems by providing information.


Concept- Sources of Data

Broadly, there two main sources of data: (i) Internal Sources (ii) External Sources 

Internal Sources

In an organization, when the data is collected from its reports and records, it is known as internal sources of data.

  • For example, a company publishes its annual report on profit and loss, total sales, loans, wages etc.
  • Data collected and compiled through internal sources is called internal data.


External Sources

External sources refer to the data collected from outside the organization.

  • For example, if a Tour and Travels Company obtains information on ‘UP Tourism’ from Uttar Pradesh Transport Corporation, it would be known as external sources of data.
  • Data collected and compiled through external sources is called external data.
  • External Data can be collected from primary as well as secondary sources.

Collected of data is of utmost importance in any statistical enquiry as no useful and valid conclusions can be drawn in case of any inadequacies in data. Data may be collected either form either from a primary source, known as ‘Primary Data’ or from a secondary source, known as ‘Secondary Data’.



Primary Data

Primary data is the data which is originally collected by an investigator or agency for the first time for some specific purpose.

  • The source from which the primary data is collected is called the primary source.
  • For example, Population census conducted by Government of India.
  • Such data is original in character as it is collected for the first time. It is first hand information.
  • Primary data once collected and published becomes Secondary Data.


Secondary Data

The data which is not directly collected but rather obtained from the published or unpublished sources, is known as Secondary Data.

  • It is also known as Second Hand Data.
  • These are not original data since the enumerators or investigators themselves do not collect these data. They simply make use of the data collected by the others.
  • For example, National Accounts Statistics published by the CSO, Economic Survey published by Government of India.


Difference Between Primary Data and Secondary Data

How basic data is collected with concepts of Sampling


Sampling Method

When only some representative items of a population are selected and data collected from these items are used for the analysis, the method is known as Sampling Method.

  • A sample is a part of universe or population.
  • The first task in selecting a sample is to identify the population. Once the population is identified, the researcher selects a representative sample as it is difficult to study the entire population.
  • A good sample is generally smaller than the population and is capable of providing reasonably accurate information about the population at a much lower cost ant shorter time.

Example: An investigator is interested in conducting an enquiry into monthly expenditure in a school comprising of total of 5,000 students. The investigator may take a sample (say, 500 students) to record evidence of whole population of 5,000 students.



There are various methods of collecting primary data. The methods commonly used for the collection of primary data are presented in the following chart:

How do we collect Data?

Collection of data is important in class 11 collection, organisation and presentation of data. It is done by the following ways:


  • The survey aims to describe characteristics like cost, worth, utility (in case of the product) and reputation, honesty, loyalty (in case of the nominee).
  • The objective of the survey is to gather data and is a method of gathering information from individuals.

Preparation of Instrument

The most prevalent type of tool employed in surveys is a questionnaire/ interview schedule. The questionnaire is either self-directed by the interviewee or conducted by the enumerator or qualified investigator. While drawing-up the questionnaire/interview schedule, the following points should be kept in mind:

  • The questionnaire should not be lengthy.
  • The array of problems should move from indefinite to distinct.
  • Questions should not be enigmatic.
  • Questions should not use binary negatives. 
  • Questions should not be leading.
  • Questions should not indicate choices. 

Mode of Data Collection

The next important topic in class 11 collection, organisation and presentation of data is the mode of data collection. The aim of probing questions is to survey the acquisition of data. There are three ways of collecting data: 

  1. Personal Interviews
  2. Mailing (questionnaire) Surveys
  3. Telephone Interviews

Personal Interviews

Personal interviews form an important part in the mode of data collection in class 11 collection, organisation and presentation of data. In this method, the researcher has the main role as he/she conducts the interviews face to face with the respondents.Personal interviews are preferred due to various reasons:

  • Highest Response Rate 
  • Allows use of all types of questions 
  • Better for using open-ended questions 
  • Allows clarification of ambiguous questions.

The personal interview has some demerits too:

  • Most expensive 
  • Possibility of influencing respondents 
  • More time taking

Mailing Questionnaire

Another important part in class 11 collection, organisation and presentation of data is the mailing questionnaire. In such a method, the data is collected through mail. The questionnaire is mailed to each person and a  request is attached to complete and return it on time. 

The advantages of this method are:

  • Least expensive 
  • The only method to reach remote areas 
  • No influence on respondents 
  • Maintains anonymity of respondents 
  • Best for sensitive questions

The disadvantages of mail survey are:

  • Cannot be used by illiterates 
  • Long response time  
  • Does not allow an explanation of unambiguous questions  
  • Reactions cannot be watched 

Telephone Interviews

In telephone interviews, the investigator asks questions over the telephone. 

The advantages of telephone interviews are:

  • Relatively low cost 
  • Relatively less influence on respondents 
  • Relatively high response rate.

The disadvantages of this method are:

  • Limited use 
  • Reactions cannot be watched 
  • Possibility of influencing respondents

Pilot Survey

The pilot survey is another important tool in class 11 collection, organisation and presentation of data.

  • After the questionnaire is ready, it is desirable to carry a try-out with a diminutive group, known as Pilot Survey or Pre-Testing of the questionnaire
  • The pilot survey serves to give a preliminary impression of the survey. 
  • It helps to pretest the questionnaire, and know the lapses and drawbacks.
  • It also aids to assess the appropriateness of questions, the accuracy of guidance, the administration of enumerators, and the expense and time required in the actual survey.



The sources of Secondary Data can broadly be classified under two heads:

1. Published Sources

2. Unpublished Sources


Published Sources

There are a number of national (government, semi-government and private) organizations and also international agencies, which collect statistical data in different fields like national income, population, prices, employment, wages, expert, import, etc. These reports are published on regular basis, i.e. annually, quarterly, monthly, fortnightly, and so on.


Important Published Sources of Secondary Data

The important published sources of secondary data are as follows:

  1. Official Publications of Central and State Governments: Government (both State and Central) generally collects information regarding economic variables like national income, saving, investment, employment, etc., and publish if after regular intervals. Some of the publications by Indian Government are Annual Economic Survey, Documents of Five-Year Plans, India-Annual Book, Census, etc.
  2. Semi-Government Publications: Semi-Government organizations like municipalities, District Boards and others also publish reports in respect of birth, death, education, sanitation and many other related fields.
  3. Reports of Committees and Commissions: Central or State Government sometimes appoint committee and commission on matters of great importance.
  • They are required to enquire into specific issues and submit the report within stipulated time.
  1. Publications of the Research Institutes: Many Research Institutes are engaged in academic research work and provide important source of secondary data.
  • Some of the important Research Institutes are: Indian Council of Agricultural Research (ICAR), Indian Statistical Institute (ISI), National Council of Educational Research and Training (NCERT), etc.
  1. International Publications: Certain International institutions publish reports from time to time regarding economic matters which are of great significance. These reports are regularly published by the agencies like United Nations Organization (UNO), World Health Organization (WHO), International Monetary Fund (I.M.F.), etc.
  2. Private Publications: Some commercial and research institutes publish reports regularly. They are like Institute of Economic Growth, Stock Exchange, National Council of Applied Economic Research, etc.
  3. Newspapers and Magazines: Various newspapers as well as magazines also collect data in respect of many social and economic aspects. Some of them are Economic Times, Financial Express, Outlook Money, Business Today, etc.

Unpublished Sources

When data collected by someone is not published and is taken by other persons for the purpose of investigation, then such data is known as ‘Unpublished Secondary Data’. For example, reports prepared by private investigation companies.

Many investigations are of private nature and their findings are not published. Such unpublished data is usually meant for the use of members only.



The Census of India provides the most complete and continuous demographic record of population. The Census is being regularly conducted every 10 years since 1881.

  • The first Census after Independence was held in 1951.
  • Indian Census has been a fascinating source of data to scholars and researchers in demography, economics, anthropology, sociology, statics and many other disciplines,
  • The responsibility of conducting the Census rests with the Office of the Registrar General and Census Commissioner, India, under Ministry of Home Affairs, Government of India.
  • The Census collects information on various aspects of population such as the size, density, sex ratio, literacy, migration, rural-urban distribution, etc.
  • Census of India is not merely a statistical operation, the data is interpreted and analysed in an interesting manner.
  • The most recent census of India was performed in 2011. It was the 15th census in an unbroken series and the 7th after independence in 1947.



National Sample Survey (NSS) was set up in 1950 on the recommendations of National Income Committee, chaired by late Prof. P.C. Mahalanobis.

  • The basic aim of setting up NSS was to fill up large gaps in statistical data for computation of national income aggregates, especially in respect of unorganized / household sector of the economy.
  • NSS was reorganized as National Sample Survey Organisation (NSSO) in March 1970. NSSO is an organization in the Ministry of Statistics and Programmed Implementation of the Government of India. It is the largest organization in India, conducting regular socio-economic surveys.
  • The NSSO conducts nation-wide surveys on socio-economic issues. The data collected by NSSO surveys, on different socio economic subjects, are released through reports and its quarterly journal Sarvekshana.
  • NSSO provides periodic estimates of literacy, school enrolment, utilisation of educational services, employment, unemployment, manufacturing and service sector enterprises morbidity, maternity, child care, utilization of the public distribution system etc.
  • NSSO is involved in three types of surveys: (i) Socio-economic surveys; (ii) Annual Survey of Industries; and (iii) Agricultural surveys.

Under socio-economic surveys, the entire responsibility of the survey from its design to release of the report is in the hands of NSSO. However, in the other two surveys, NSSO is entrusted with collection of data from the field only.

  • NSSO organization has four divisions:

1. Surveys Design and Research Division (SDRD)

2. Field Operation Division (FOD)

3. Data Processing Division (DPD)

4. Co-ordination and Publication Division (CPD)


Activities of NSSO

(NSSO) conducts the following activities:

1. Carries out multi-subject integrated socio-economic surveys;

2. Undertakes field work for the Annual Survey of Industries and follows-up surveys of Economic Census;

3. Conducts sample checks on area enumeration and crop estimation surveys of State Statistical agencies;

4. Prepares the urban frames useful in drawing of urban samples;

5. Collects price data from rural and urban sectors;

6. Conducts ad-hoc surveys and pilot enquiries for methodological studies.


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