From the PEESS v1.0 to the validated PEESS™ v 2.0. The instrument layout and overall design went through several iterative drafts based on patient and parent-proxy feedback through focus interviews and separate cognitive interviews. For example, participants favored presenting frequency and severity of particular items side by side rather than on two separate pages.
Franciosi et al. BMC Gastroenterology 2011 11:126 doi:10.1186/1471-230X-11-126