Retention Heatmap

A retention heatmap is the cohort triangle with its cells filled by color intensity so the retention pattern of several cohorts over time is seen at a glance.

A retention heatmap is not a metric but a display method: it translates each cell's retention number into color so the eye sees the pattern instead of reading dozens of percentages. Darker columns moving rightward mean retention falls as cohort age rises (natural), but if a whole row is lighter than the rows above it, that cohort retained better overall — a clue to a product change's effect. The general heatmap weakness applies here too: the chosen color scale can enlarge small differences or wash out big ones, so the color scale must be honest and fixed. Another trap is coloring cells of very small cohorts; a low-population cohort's noisy percentage can make a random 'hot' cell that is not a real pattern.