The AlgoViz Project Cliff Shaffer Department of Computer Science Virginia Tech Blacksburg, VA

AVs: The Problem (1) Some identifiable successes for AVs – Lots of “no significant difference” results – But some AVs have been shown to be pedagogically effective – Steady progress is being made in understanding how to design and use AVs

AVs: The Problem (2) AVs have high faculty and student favorability ratings But AVs have little overall impact on education

AV Community (AlgoViz) Solution – Build a community of users/developers – Better disseminate best practices information NSF CCLI grant, connections to NSDL/Ensemble project

AlgoViz Wiki Catalog Data A collection of links to nearly 450 AVs The collection allows us to do some analysis – Topical Distribution (sorting >30%, linear structures >10%) – Who/where (60% by teams/major projects) – Quality (68/207/113) – Access Stability (a lot of URL churn, a few get lost)

Next Step: NSDL Project Proposal Create a new model of “dissemination” to lower barriers to access Move away from the “digital library” model of users coming to collections Notification via social networks Focus on “community-driven” content development – Discussion, review, ratings – Think Amazon, but we have critical mass issues

OpenAlgViz SourceForge Project Collect and host AV software Exemplar AVs Software libraries for AV developers Software infrastructure

Algorithm Visualization: Features Study the details of AV implementation in an effort to understand how to best design AVs – Pseudocode display – Back Button – Example (test) data vs. students entering tests – Animation vs. “next” step

Tutorials vs. AVs Integrated text and activities (applets) Guide questions/directed activity Built-in quizzing (future) Explanatory applets vs. “analysis” applets Takes a long time to develop (several students over two-three years) In progress (at VT): – Hashing – Memory management – Search Trees

AVs: Hashing Tutorial Section 1: Standard lecture and textbook for one week Section 2: In-class tutorial use for one week (same material) Student reaction: Universally positive for tutorial Section 2 had significantly better score in post- test