usability testing with three people - how to discover why mappers are confused by your software
Usability testing can be done without hordes of users to observe, in fact just three people is likely to give very useful hints.
And it is almost certainly more useful than expected, and your software is likely not as good as you expect.
This is based on my experience with using user testing while developing StreetComplete.
Active OpenStreetMap mapper and contributor to software powering OpenStreetMap. Contributed some minor improvements to multiple editors and significant improvements to StreetComplete.
Mapper active since 2013, especially interested in mapping bicycle infrastructure, hiking trails, parks.
Involved in improving documentation about existing tagging schemas by contributing to OpenStreetMap Wiki. Active also in inventing new tagging schema where existing ones were insufficient.