Early work on database reorganization, physical file structures, indexing algorithms, and performance optimization. Subsequent work with graduate students led to many important software tools that influenced future research:
- Early hypertext system, Hyperties, which was a precursor for the web.
- Direct manipulation and dynamic queries concepts which led to Spotfire's commercial success.
- Touchscreen designs for small keyboards, home controls, artwork, and professional applications.
- Series of time series data analysis tools e.g. TimeSearcher.
- Creator of treemap concept of nested visualization of hierarchies with size and color coding.
- Hierarchical Clustering Explorer to analyze high-dimensional numeric data sets.
- Research, development, and evaluation of electronic classrooms.
- Medical informatics applications including patient histories and temporal event sequences: Lifelines, LifeLines2, LifeFlow, and EventFlow.
- Network analysis and visualization software (free, open source) NodeXL and the NodeXL Graph Gallery.