Attending radiologists routinely edit radiology trainee dictated preliminary reports as part of standard workflow models. Time constraints, high volume, and spatial separation may not always facilitate clear discussion of these changes with trainees. However, these edits can represent significant teaching moments that are lost if they are not communicated back to trainees. We created an electronic method for retrieving and displaying changes made to resident written preliminary reports by attending radiologists during the process of radiology report finalization. The Radiology Information System is queried. Preliminary and final radiology reports, as well as report metadata, are extracted and stored in a database indexed by accession number and trainee/radiologist identity. A web application presents to trainees their 100 most recent preliminary and final report pairs both side by side and in a "track changes" mode. Web utilization audits showed regular utilization by trainees. Surveyed residents stated they compared reports for educational value, to improve future reports, and to improve patient care. Residents stated that they compared reports more frequently after deployment of this software solution and that regular assessment of their work using the Report Comparator allowed them to routinely improve future report quality and improved radiological understanding. In an era with increasing workload demands, trainee work hour restrictions, and decentralization of department resources (e.g., faculty, PACS), this solution helps to retain an important part of the educational experience that would have otherwise run the risk of being lost and provides it to the trainees in an efficient and highly consumable manner.