Analysis
Vanity metric
Also called ego metric.
Vanity metric is a number that grows easily and never changes a decision. It looks good in a deck and tells you nothing to do.
How it is measured
Test any figure by asking what you would do differently if it halved. If the answer is nothing, it is vanity. Cumulative totals, such as lifetime signups, are the classic case because they cannot fall.
Compare it with its actionable cousin. 'Total registered users' has an actionable cousin in 'users who completed setup this week'. Replace the first with the second on the main screen.
Worked example
A recipe app announces 500,000 downloads. Weekly active cooks, people who save or start a recipe, are 21,000. The download count grows by thousands a week even though weekly actives drift down.
The team replaces the download banner with weekly active cooks and sets an onboarding goal. Within two months actives are 26,000 and the growth is real.
How it differs
A vanity metric flatters. An actionable metric guides. Pageviews can be either, depending on whether anyone would act on a change.
Common errors
Reporting lifetime totals. Counting followers. Celebrating pageviews from a one-off link. Using the number to hide a flat product. Accusing a metric without asking what decision it informs.
In practice
Review your top-line report and mark each number with the action it would trigger. For any with no action, swap in a rate or a recent-window count.