The study protocol is a document outlining the design of a study, describing the objectives, methodology, and overall organization of the research to be carried out forming a template and guide to the research process as a whole. 

The study protocol can contribute to enhancing the scientific integrity of a study and for providing better study documentation, efficiency, and communications, all through careful prestudy planning.

This is why a study protocol is important for developing a questionnaire that would be both valid and reliable for a research study.