Captions short enough for a stamped briefing
Writing chart captions for departmental reporting so a director can read the point before the ink dries on the stamp.
A useful caption answers three questions in one or two lines: what was counted, over which period, and what changed since the last pack. Leave methodology footnotes for the appendix.
If your chart of service delivery metrics needs a paragraph to make sense, the chart is doing too much. Split indicators, or move the debate into the narrative section where a director expects prose.