Following precautions should be taken While using secondary data :
1. Information should be gathered regarding the qualification, honesty, biasness and experience of the previous investigator.
2. It should kept is mind whether the objective and area of the previous investigation was same as current investigation or not.
3. The method of collecting data by the previous investigators should be trustworthy.
4. Each unit of previous investigation should be equivalent to each unit of current investigation.
5. The published data should be highly accurate.
6. Time taken for previous investigation should be normal.
7. The shape of sample should be proper.
8. The sources of published data should be trustworthy.
9. There should be homogeniety among the published data.
10.Time of published data should be tentatively checked.
