Statistics for SSC-CGL Tier-II (Paper-III) – Part-5

Secondary data

Secondary data are collected by investigators from sources other than primary respondents. Secondary data are collected from both, published and unpublished sources. It means secondary data are those data which have been already collected and analysed by some earlier agency for its own use; and later the same data are used by a different agency. 

According to W.A.Neiswanger, ‘A primary source is a publication in which the data are published by the same authority which gathered and analysed them.  A secondary source is a publication, reporting the data which have been gathered by other authorities and for which others are responsible’ .

Sources of Secondary data:

In most of the studies the investigator finds it impracticable to collect first-hand information on all related issues and as such he makes use of the data collected by others.  There is a vast amount of published information from which statistical studies may be made and fresh statistics are constantly in a state of production.

The sources of secondary data can broadly be classified under two heads:

1. Published sources, and

2. Unpublished sources.

1.  Published Sources:

The various sources of published data are:

1. Reports and official publications of

(i) International bodies such as the International Monetary Fund, International Finance Corporation and United Nations Organisation.

(ii) Central and State Governments such as the Report of the Tandon Committee and Pay Commission.

2. Semi-official publication of  various local bodies such as Municipal Corporations and District Boards.

3.  Private publications-such as the publications of –

(i) Trade and professional bodies such as the Federation of Indian Chambers of Commerce and Institute of Chartered Accountants.

(ii) Financial and economic journals such as ‘ Commerce’ , ‘ Capital’ and ‘ Indian Finance’ .

(iii) Annual reports of joint stock companies.

(iv)  Publications brought out by research agencies, research scholars, etc.

It should be noted that the publications mentioned above vary with regard to the periodically of publication.  Some are published at regular intervals (yearly, monthly, weekly etc.,) whereas others are ad hoc publications, i.e., with no regularity about periodicity of publications.

Note: A lot of secondary data is available in the internet. We can access it at any time for the further studies.

2. Unpublished Sources

All statistical material is not always published. There are various sources of unpublished data such as records maintained by various Government and private offices, studies made by research institutions, scholars, etc.  Such sources can also be used where necessary Precautions in the use of  Secondary data

The following are some of the points that are to be considered in the use of secondary data

1. How the data has been collected and processed

2. The accuracy of the data

3. How far the data has been summarized

4. How comparable the data is with other tabulations

5. How to interpret the data, especially when figures collected for one purpose is used for another. Generally speaking, with secondary data, people have to compromise between what they want and what they are able to find.

Merits and Demerits of Secondary Data:

1. Secondary data is cheap to obtain. Many government publications are relatively cheap and libraries stock quantities of secondary data produced by the government, by companies and other organisations.

2. Large quantities of secondary data can be got through internet.

3. Much of the secondary data available has been collected for many years and therefore it can be used to plot trends.

4. Secondary data is of value to:

– The government – help in making decisions and planning future policy.

– Business and industry – in areas such as marketing, and sales in order to appreciate the general economic and social conditions and to provide information on competitors.

– Research organisations – by providing social, economical and industrial information.

Precautions in the use of Secondary Data

While using secondary data for the study, users have to be careful. Sometimes, the data published by an individual researcher may be full of errors and even drawn from an inadequate sample. Some factors to keep in mind while using the data from secondary sources are listed below :

Adequacy :

Sometimes data available from the secondary, sources are not adequate for the investigation. Data may be either  form a different time period, or partially fulfil the requirement of the study. Therefore, adequacy of the data must be ensured before conducting the study.

Reliability :

Before using secondary data, its reliability must be taken into consideration.

For example, the reliability of sample size and the sampling method used in the collection of data may be taken into consideration. Besides, the investigator has also to know the degree of bias in collection of data.

Suitability :

The investigator has to check whether the data is suitable for the purpose of the research study. Sometimes, the secondary data may be suitable for tabular presentation, but, unsuitable for statistical analysis.

The investigator has to take all these factors into consideration before using the secondary data.


Data refers to any group of measurements that happen to interest us. These measurements provide information the decision maker uses. Data are the foundation of any statistical investigation and the job of collecting the data is the same for a statistician as collecting stone, mortar, cement, bricks etc. is for a builder. So, data refers to the set of observations, values, elements or objects under consideration. The complete set of all possible elements or objects is called a population. Each of the elements is called a piece of data.


For understanding the nature of data, it becomes necessary to study about the various forms of data, as shown below :

* Qualitative and Quantitative Data

* Continuous and Discrete Data

 * Primary and Secondary Data

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