Collection of data is the basic activity of statistical science. It means collection of facts and figures relating to particular phenomenon under the study of any problem whether it is in business economics, social or natural sciences.
Such material can be obtained directly from the individual units, called primary sources or from the material published earlier elsewhere known as the secondary sources.
Difference between Primary & Secondary Data
| Primary Data|| Secondary Data|
| Basis nature ||Primary data are original and are collected for the first time||Data which are collected earlier by someone else, and which are now in published or unpublished state. |
| Collecting Agency||These data are collected by the investigator himself||Secondary data were collected earlier by some other person.|
| Post collection alterations||These data do not need alteration as they are according to the requirement of the investigation||These have to be analyzed and necessary changes have to be made to make them useful as per the requirem|
| Time & Money||More time, energy and money has to be spent in collection of these data. ||Comparatively less time and money is to be spent.|