In this study, a quantitative approach was used to assess an Electronic Patient Record worklist function introduced to prevent radiology reports from being overlooked by the responsible clinicians. The function reduced the rate of overlooked reports, but was not able to eliminate it. Not all reports were identified by the automatic worklist function. Clinicians did not use the worklists to detect new reports. Our results suggest that this was not the result of insufficient user training or user errors, but rather that the worklists function did not comply with the way clinical work was organised and performed. Quantitative methods as used in this study are suggested as supplementary to the traditional qualitative methods.