There is arguably no more important document than the instrument that is used to acquire the data from the clinical trial, with the exception of the protocol, which specifies the conduct of that trial. The quality of the data collected relies first and foremost on the quality of that instrument. No matter how much time and effort go into conducting the trial, if the correct data points were not collected, a meaningful analysis may not be possible. It follows, therefore, that the design, development and quality assurance of such an instrument must be given the utmost attention.
— Good Clinical Data Management Practices, Version 4, October 2005, Society for Clinical Data Management