HANDS is a new programming system for children that was designed for usability. This paper examines the effectiveness of three features of HANDS: queries, aggregate operations, and data visibility. The system is compared with a limited version that lacks these features. In the limited version, programmers can achieve the same results but must use more traditional programming techniques. Children using the full-featured HANDS system performed significantly better than their peers who used the limited version. This provides evidence that usability of programming systems can be improved by including these features. Keywords End-user programming, psychology of programming, user studies, programming languages.
John F. Pane, Brad A. Myers