An electronic encounter log's failure to scale.

We have developed a series of Electronic Student Encounter Log (ESEL) programs intended to introduce medical students to promising medical informatics concepts. We attempted to expand ESELs scope from ambulatory settings to all hospital venues and to track progress toward educational goals. Students were confused and frustrated by a previously fast interface and delayed feedback. Numerous scaling problems emerged. Our attempt to address these problems in an extensive revision, developed for the latest affordable hardware and operating system, failed due to new data-corrupting crashes. Risks of scaling up and other familiar software development lessons are reinforced.