Every chart on a dashboard should answer a specific question. If you cannot state the question, the chart should not be there.
Look for: understanding the audience and their decisions, leading with the most important metric, progressive disclosure (summary to detail), consistent formatting, appropriate chart types, avoiding clutter, providing context (targets, comparisons, trends), and making it actionable rather than just informational.
Tests communication and design thinking. Analysts who create cluttered, everything-on-one-page dashboards frustrate stakeholders. Those who design with decision-making in mind create tools people actually use.