Objective To assess how interpretation of abnormalities at the oesophago-gastric junction (OGJ) when making a diagnosis of Barrett's oesophagus (BO) varies between endoscopists and to examine the impact of the endoscopy experience on these decisions.

Design/setting Members of the Irish Society of Gastroenterology who regularly perform gastroscopy were invited to participate in a web based image assessment study.

Interventions Questions were posed to ascertain level of endoscopy experience, and participants were asked to indicate the presence or absence of BO in 12 endoscopic images of the OGJ.

Outcome measures Primary outcome was overall level of agreement in responses and relationship to endoscopy experience.

Results The responses of 65 clinicians regularly performing gastroscopy were analysed. In 3/12 images, showing typical long segment BO, there was a strong consensus on the endoscopic diagnosis (>95% agreement). However, agreement was fair to poor (κ for multiple raters, 0.31) on the presence or absence of short BO segments at endoscopy. Minimal differences were observed between experienced endoscopists (individuals with >10 years' endoscopy experience) and less experienced counterparts in the threshold for BO diagnosis. Inter-endoscopist agreement overall was not significantly better within the more experienced group.

Conclusion The study demonstrates low interobserver agreement in endoscopic diagnosis of (short segment) BO, even among experienced endoscopists. Given the costs associated with endoscopic surveillance of BO, prompt efforts to promote consensus diagnosis and improve agreement are required as an important quality improvement measure in this area.