Lead with the few metrics tied to their goals, each with context — target, trend, and variance — not a bare number. One screen, no scrolling, an obvious good/bad direction. Detail lives one click down for whoever needs it. The 30-second read is are we on track and where is the problem.
How to answer it
Thirty seconds answers two questions: are we on track, and if not, where is the problem. Everything on the screen serves one of those.
Three to five metrics, chosen from their goals, not from what is easy to measure. Revenue, growth, retention, margin, one operational number; whatever they are accountable for.
Each metric with context: current value, target, variance to target, and the trend over the relevant period. A number alone forces a mental lookup; number plus target plus arrow is readable at a glance.
One screen. No scrolling, no tabs on the first view. If it does not fit, the list is too long.
A consistent visual language for good and bad: colour and direction mean the same thing on every tile, so the eye finds the red one immediately.
One click to detail. The breakdown by region or product lives below or behind the tile, for the person who now has a question.
Refresh cadence matched to the decision: daily for operations, weekly for most executive views, and the refresh time stated on the page so nobody presents stale numbers.
Before shipping, test the 30 seconds literally: show it to someone for half a minute, take it away, and ask what they would do. If they cannot say, the design has failed, whatever it looks like.
What they are checking: that you design for the two questions, with targets and trends, and cut everything else.
Common mistake: a "summary" page that is itself a wall of small charts.