STUDY DESIGNS Exercise

STUDY DESIGNSExercise

Algorithm for classification of types of clinical research*

*THE LANCET 2002;359:57- 61Example - 1Does the investigator assign exposure?No. Observational studyIs there any comparison group?No. Descriptive studyAre exposure and outcome measured simultaneously?Yes. Cross-sectional study (Descriptive cross sectional design)

Example - 2Does the investigator assign exposure?No. Observational studyIs there any comparison group?Yes. Analytical studyAre exposure and outcome measured simultaneously?No. Not a cross-sectional studyDoes the study move from exposure to outcome?Yes. Cohort studyExample - 3Does the investigator assign exposure?Yes. Experimental studyIs the subject are randomly allocated to the exposure?Yes. Randomized Controlled TrialExample - 4Does the investigator assign exposure?No. Observational studyIs there any comparison group?No. Descriptive studyThere is only a single case (no population) involved There is no comparisonCase reportExample - 5Does the investigator assign exposure?No. Observational studyIs there any comparison group?Yes. Analytical studyAre exposure and outcome measured simultaneously?No. Not a cross-sectional studyDoes the study move from exposure to outcome?No. Not a Cohort study Does the study move from outcome to exposure?Yes. Case-control study