How are deltas calculated?

The previous window, and nothing else

A delta answers one question: how does this window compare with the equal window right before it, under the same filters? A 30-day report compares with the 30 days before it. A 7-day report compares with the 7 days before that. If you set two absolute dates, the comparison is the same number of days immediately prior. The comparison period is never a choice, so nobody can pick a baseline that flatters the current month.

Because the window and the filters travel together, a report filtered to one engine, one country, or one persona compares against the same cut of the earlier period. The delta you read on a persona line is that persona against its own past, not against the account as a whole.

Why movers use share rather than counts

The number of answers in a window drifts. If movers ranked on raw counts, a busier period would look like growth on every row. Instead each row's share of its window's total is compared with its share of the previous window, and the change is reported in percentage points. When the number of answers drifts by more than a quarter between the two windows, a banner above the tables says so.

When a delta is withheld

A dash means the platform declined to compute a change, not that nothing changed. A prompt delta needs at least five answers in both windows. A row with no previous window to compare against stays blank rather than reading as a drop. Every row in the Movers tab also carries a status, new, grew, shrank, dropped, or flat, so the direction is visible before you read the number.