A case report form (CRF, or case study report form) is a paper or electronic questionnaire specifically used in clinical trial research to facilitate data analysis and test hypotheses. The case report form is the tool used by the sponsor of the clinical trial to collect data from each participating patient. All data on each patient participating in a clinical trial are held and/or documented in the CRF, including adverse events. Case report forms contain data obtained during the patient’s participation in the clinical trial. Though paper CRFs are still used largely, CRFs (eCRFs) is gaining popularity due to the advantages they offer such as improved data quality, online discrepancy management, and faster database lock, etc.