Decisions, Decisions: Dashboards and Reports
Decisions, Decisions: Dashboards and Reports tests whether you can turn a model into a visual product that drives action. Expect chart choice, dashboard versus report, layout, interactivity, accessibility, and stakeholder delivery.
Dashboard versus report
A dashboard monitors current state at a glance: KPIs, minimal text, interactivity, frequent refresh. A report explains detail: static or scheduled, narrative, distribution, and an audit trail. Choose by cadence and decision type, not by tool. Monitoring needs a dashboard; a monthly business review needs a report.
Chart selection
Comparison: bar. Trend over time: line. Distribution: histogram or box plot. Relationship: scatter. Composition: stacked bar; avoid pie charts beyond three or four slices. Part-to-whole over time: area. Maps only for geography. Rank with sorted bars. Avoid 3D, dual axes, and truncated axes that exaggerate change.
Design hierarchy
Use an inverted pyramid: headline KPI, then trend, breakdown, and detail. The five-second rule: the main message must land immediately. Pre-attentive attributes - position, size, color - guide the eye. Use color sparingly, keep contrast accessible, and never rely on red/green alone. Add filters, drill-down, and tooltips only when they answer a real question. Keep number formats and date ranges consistent.
Delivery and storytelling
Match the audience: executives need the decision and the ask; managers need trends and exceptions; analysts need detail and export. Structure the narrative as situation, complication, resolution. Annotate anomalies. Schedule and subscribe reports, version them, document metric definitions, and add alt text and keyboard access.
Worked example
A support team must reduce backlog. The dashboard headline is open tickets versus SLA; a 90-day line shows backlog trend; a sorted bar shows backlog by team; a table lists the 20 oldest tickets; filters are region and priority. Reasoning: the decision is monitoring, so a dashboard beats a report; a line shows trend, a sorted bar shows comparison, and a table supports action; annotations explain spikes; a pie chart would obscure ranking.
Traps that cost marks
- Treating a dashboard as a data dump.
- Pie charts for many categories.
- Dual axes that imply false correlation.
- Missing baselines and inconsistent date ranges.
- Interactivity without a purpose.
- Inaccessible color encoding and no freshness timestamp or owner.