The data which is not collected by a person, not for his own use may not be much reliable.

Because these data have not been collected for the predetermined purpose. So these data may not be in a position to fully solve the problem in hand.

So while using these data, the following three factors must be kept in view:

(i) Are data reliable?


(ii) Are data adequate? ; and

(iii) Are data suitable for the enquiry?

“Statistics, especially other people’s statistics are full of pitfalls for the users.” —Connor

So in order to get its full use by the researcher one should be cautious about the following precautions.



(i) The analyst must be aware of the purpose of enquiry. The data must suit the purpose.

(ii) The analyst must see that the person, who collects that data, must be honest, experienced and unbiased.

(iii) There should not have been change of conditions now and then when these were collected. The data which was collected during other times may not suit during the days of calamities.


(iv) The units in which these data are collected must be same as needed in present analysis. Change of units may lead to wrong conclusions.

(v) As the data presently to be used has been collected by many enumerators, their approach, experience and methods may have been different.

(vi) If comparison is to be made, the investigator should be intelligent enough to make differences, as even small difference can make big change in results.