ABC of Content Validation and Content Validity Index Calculation

There are five sources of validity evidence that are content, response process, internal structure, relation to other variables, and consequences. Content validity is the extent of a measurement tool represents the measured construct and it is considered as an essential evidence to support the validity of a measurement tool such as a questionnaire for research. Since content validity is vital to ensure the overall validity, therefore content validation should be performed systematically based on the evidence and best practice. This paper describes a systematic approach to quantify content validity in the form of content validity index based on the evidence and best practice.