During colonoscopy, all detected polyps are resected and sent for histopathological assessment by the pathologist to determine the interval for a surveillance colonoscopy. Diminutive polyps (1-5 mm), which constitute up to 60% of all polyps, are rarely malignant (0-0.1%). If it would be possible to predict the histology of these diminutive polyps during colonoscopy, histopathological examination could be omitted. This 'optical diagnosis strategy' by endoscopists could lead to significant cost savings. For safe implementation of this strategy in daily practice, its accuracy must meet minimum thresholds. The development of 'electronic chromoendoscopy' has led to more accurate optical diagnosis. However, research shows that some endoscopists are yet not able to meet the required accuracy thresholds. Due to this variability in accuracy and the absence of an accreditation system implementation of the optical diagnosis strategy in daily practice is still unsuccessful.