Primary and secondary sources of Data collection and its limitations

There are two main approaches for data collection about a problem, person or a phenomenon.

Primary Data

There are times when the information must be collected. Sources used in the this approach are called as primary sources.

Examples of information collected through primary sources are:

Finding out attitude of a community towards health services.
estimate the health needs of a community.
evaluating a social program.
determining the job satisfaction of the employees of an organization.
Estimating the qualities of services provided by a worker.

In summary, primary sources provide first hand data, whereas secondary sources provide second hand data.

Primary sources of data collection are:

Observations which may be participant or non participant.
Interviews which may be structured or non structured.
Questionnaire which may be mailed or collective questionnaire.

Secondary Data

Sometimes information required is already available and need only to be extracted. Information gathered using this approach is said to be collected from secondary sources.

Example of secondary sources of data collection are:

use of census data to obtain information on the age-sex structure of a population.
the use of hospital record to find out the mortality patterns of a particular population.
the use of an organization record to estimate its activities.
data collection through articles, journals, magazines and books.
It may be documents like, govt. publications, earlier research, census forms or personal records.

Limitations while using data from secondary sources

When using data from secondary sources you need to be careful as there may be certain problems with the availability, format and quality of data. The extent of these problems varies from source to source. While using such data some issues you should keep in mind are:

Validity and reliability

The validity and reliability of information may vary from source to source. For example data collection through census may be more valid than data collection through personal diaries.

Personal bias

The information obtained from personal diaries, magazines and newspapers may be personal bias, as these writers are likely to exhibit less rigorousness and objectivity than one would expect in a research report.

Availability of data

It is common for beginning researchers to assume that the required data will be available. But you cannot and should not make this assumption. Therefore, it is important to make sure that the required data is available before you proceed further with your study.

Format

Before deciding to use the data from the secondary sources, it is equally important to make sure that the data are available in the required format. For example, you might need to analyse the age in the categories 23-33, 34-48 etc., but in your sources age may be categorized differently, e.g., 21-24, 25-29 etc.