T-shirt estimation is the idea, that estimation of user stories or tasks should be done at a rather rough level (t-shirt sizes) rather than precise hour or even storypoints. The idea is to save time, frustration and avoiding a false sense of knowledge by not trying to be more precise than actually usefull. It often turns out to be rather more precise than expected and with a good knowledge-pr-time-spend ratio.
Story mapping is a tehchnique used for both scoping and release planning of new projects and enhancements to existing products. It is very much inspired by the work of Jeff Patton made popular through his 2008 blog post “The new backlog is a map”, but in an adjusted form and combined with journey mapping practices and techniques. This post is a practical guide of how to conduct a story mapping workshop with lists of things to rememer and do.