major research methods (social sciences)

Each discipline of science has its own ways of doing research, e.g. social sciences primarily use qualitative and non-experimental methods, with occasional use of experimental methods.
Selected methods are natural observation, historical research, ethno-graphic research, cross-sectional study, longitudinal study, cohort study, case study, correlational research, model building, action research, and participatory learning and action (PLA).
Some of these methods are also employed by natural scientists.

C. George Thomas, "Research Methodology and Scientific Writing", Springer, Cham, Switzerland, 2nd edition, p 65, 25 Feb 2021 (), url https://isbnsearch.org/isbn/9783030648640 [].