Usability Case Study Datamaps Visualization Chris North CS

Usability Case Study: Datamaps Visualization Chris North CS 3724: HCI

Data. Maps • • http: //infovis. cs. vt. edu/census/Datamaps. htm Color map Select for detail table Histo Sliders filter Plot brushing • Sticky note help

Usability Videos • Succeeded at easy task • Sticky Help sometimes useful, terminology tricky • Problems: • • Map navigation, want to go ‘back’ Click instead of drag sliders Think histogram is barchart, each bar is a state? Never colored map Never used plot How to find other data fields (More Variables) Filtering mis-interpreted Stuck in table, not using visualization

Re-design Ideas • Users familiar with data ‘table’ concept • Variables (population, …) • States • Table-first approach • All variables accessible via treeview (Win Explr) • Data shown for selected states • Entice users to visualization • Pop-up when click variable • “drop here”

Wizard of Oz • New table design successful • “drop here” failed (drop what here? ) • Should group map and histo for an attribute • Wiz-of-Oz hard with dynamic visualization!

Histo Slider Re-design • Designs: • • Smooth curve (black), instead of bars Selection range (yellow), selection curve (red) Brushing (direct selection in histo) vs sliders Slider thumb variations – On, above, below – Squares, triangles – Between thumbs: bar, button, circle • Text input boxes, range • Results: • Smooth curve successful, understood ‘humps’ • Brushing used, sliders not used • Brushing: clicked first, but eventually drag • Text boxes good, but can override vis.

Clean Design • Rob Miller, MIT: visually integrated design • Brad Paley, Didi / Columbia: eliminate typical windows paraphernalia

Other… • • • Moving users from table to visualization Progressive usage Post-it help Histogram design, interaction Brushing instead of filtering, single interaction model

Fun: Verbal-visual conflict

Fun: How to Lie with Visualization

The hidden 0 -points • Lie factor = ?