<core_definition> "A dashboard is a visual display of the most important information needed to achieve one or more objectives; consolidated and arranged on a single screen so the information can be monitored at a glance." — Stephen Few </core_definition>
<essential_principles>
<single_screen_rule> A dashboard must fit on a single screen without scrolling. If it requires scrolling, it's not a dashboard—it's a report. The constraint forces prioritization. </single_screen_rule>
<at_a_glance> Information must be perceivable at a glance. This means:
- •No hunting for data
- •No mental calculations required
- •Immediate pattern recognition
- •Exceptions visible without interaction </at_a_glance>
<eloquence_through_simplicity> Reduce to the minimum necessary:
- •Reduce non-data pixels: Eliminate unnecessary ones, de-emphasize others
- •Enhance data pixels: Eliminate unneeded ones, highlight the most important
Every pixel should earn its place. If removing something loses no information, remove it. </eloquence_through_simplicity>
<color_discipline> Color is a scarce resource. Use it only for meaning:
- •Default: Grayscale for most data and UI elements
- •Reserve bright colors: Only for alerts, exceptions, highlights
- •Consistency: Same color = same meaning across all dashboards
- •When everything is bright, nothing stands out </color_discipline>
<appropriate_precision> Match precision to need:
- •Executives need trends and exceptions, not decimal places
- •Analysts need exact values for investigation
- •Operations needs real-time status, not historical depth
Don't display more precision than the viewer can use. </appropriate_precision>
</essential_principles>
<dashboard_types> Three primary types, each with different design requirements:
| Type | Purpose | Update | Interaction | Focus |
|---|---|---|---|---|
| Strategic | Long-term oversight | Daily/Weekly | Minimal | Trends, KPIs |
| Analytical | Deep investigation | As needed | High | Drill-down, comparison |
| Operational | Real-time monitoring | Seconds/Minutes | Low | Alerts, current state |
Most dashboards serve ONE type. Mixing types creates confusion. </dashboard_types>
<display_media_hierarchy> Choose the right display for the data:
| Data Type | Best Display | Avoid |
|---|---|---|
| Single KPI vs target | Bullet graph | Gauge, pie chart |
| Trend over time | Sparkline | Full chart with axes |
| Distribution | Strip plot, histogram | Pie chart |
| Part-to-whole | Stacked bar | 3D pie, donut |
| Comparison | Bar chart | Radar chart |
| Geographic | Choropleth | 3D globe |
| Correlation | Scatter plot | Bubble chart |
| Current status | Indicator + value | Animation |
Rule: The simplest display that communicates the data wins. </display_media_hierarchy>
<intake> What are you designing?- •New dashboard — Need to determine type, metrics, layout
- •Reviewing existing dashboard — Audit against Few's principles
- •Specific component — Bullet graph, sparklines, KPI cards, alerts
- •Display media selection — What chart type for this data?
- •Color/layout guidance — Visual design decisions </intake>
<quick_audit_checklist> Run through this for any dashboard:
Structure
- • Fits on single screen without scrolling?
- • Serves ONE dashboard type (strategic/analytical/operational)?
- • Most important information in top-left quadrant?
Display Media
- • Using bullet graphs instead of gauges?
- • Sparklines for trends instead of full charts?
- • No pie charts, 3D effects, or decorative elements?
Visual Design
- • Mostly grayscale with color reserved for meaning?
- • Adequate white space between groups?
- • Consistent alignment and sizing?
Data
- • Context provided (vs. target, vs. prior period)?
- • Appropriate precision for audience?
- • Exceptions highlighted, not hidden?
Perception
- • Can grasp key message in <5 seconds?
- • Related items grouped by proximity?
- • No chartjunk, gradients, or decorative images? </quick_audit_checklist>
<anti_patterns> Few's most critical warnings:
Gauges and Meters — Waste space, encode poorly, look "impressive" but communicate little. Replace with bullet graphs.
Pie Charts — Humans judge angles poorly. Use bar charts for comparison, bullet graphs for target tracking.
Traffic Lights Alone — Red/yellow/green without values loses critical context. Always show the number alongside status.
Bright Color Everywhere — When everything screams for attention, nothing gets it. Default to gray, highlight exceptions.
Scrolling Dashboards — If it scrolls, it's not a dashboard. Prioritize ruthlessly.
Decoration — Gradients, 3D effects, background images, corporate logos in data area. Every non-data pixel costs attention. </anti_patterns>
<integration> This skill works with: - **d3-expert** — Implementation patterns for bullet graphs, sparklines - **stakeholder-adaptation** — Adjust dashboard for executive vs. analyst audience - **charts-visualization-review** — Complementary principles (data-ink ratio, lie factor) - **behavioral-health-viz-patterns** — Domain-specific dashboard patterns </integration>