Textbook of Usability

Dashboard design concerns the arrangement of multiple data displays on a single screen for monitoring, analysis, or decision support. Dashboards are distinct usability challenges because the designer must balance comprehensiveness (showing all relevant data) against cognitive load (not overwhelming the viewer).

Stephen Few's influential work on dashboard design emphasises:

• Fit on a single screen — if scrolling is required, the viewer cannot maintain simultaneous awareness of all data
• Group related data using Gestalt proximity and similarity
• Provide context — raw numbers are meaningless without targets, thresholds, trends, and comparisons
• Use appropriate chart types — bullet graphs for target tracking, sparklines for trends, bar charts for comparisons
• Avoid gauges and dials — they waste space and provide poor precision
• Apply the dark cockpit principle — normal states should be visually quiet; only anomalies attract attention

Dashboard alerts face the same challenge as clinical decision support: too many alerts cause fatigue and dismissal. Alert thresholds should be carefully calibrated to minimise false positives.

Common dashboard failure modes:

• Vanity metrics that look impressive but don't drive decisions
• Chartjunk that prioritises aesthetics over clarity
• Context-free numbers that users can't interpret
• Gauges and dials replicating physical instruments without their advantages
• Too many colours competing for attention
• Poor prioritisation — critical data drowned in secondary information

Dashboard design is fundamentally a cognitive load management problem. Every design decision should serve the viewer's ability to detect what matters and ignore what doesn't.