Books and records are the primary sources of data in

Books and records serve as the primary sources of data in historical research.

Participatory research generates data through the active involvement of the community studied.

Clinical research draws data from patients, cases, and controlled treatment settings.

Laboratory research produces data by observing manipulated conditions under controlled experiments.

Historical sources are judged by external criticism for authenticity and internal criticism for accuracy.

Primary sources are original records, while secondary sources merely report on them.