While analysis of data, allocation into similar groups is done to ensure-
In a case-control study, the controls may differ from cases in a number of factors like age, sex, occupation. - it is necessary to ensure comparability between cases and controls. - this process is called matching. Reference: Park's textbook of preventive and social medicine, 23rd edition, pg no:72
Comparability
Accuracy
Validity
Sensitivity
Epidemiology