Does Senso’s Citation Rate match the IAB definition?

No, and the difference is the denominator rather than the arithmetic. The IAB defines Citation Rate as responses containing a citation divided by total responses. Senso divides by D, the answers that cited anything at all.

Both are legitimate; they answer different questions. Over total responses you learn how often a citation of you appears at all, which moves whenever the models decide to cite less. Over D you learn, of the answers that did cite something, how often that something was you — which isolates your standing from platform-wide changes in citation behavior.

Senso’s glossary names the IAB’s version explicitly as something other than its Citation Rate, so the two never get mixed by accident. If you are reporting to a brief written against the IAB framework, compute it from the raw counts: divide the tier’s cited_run_count by answered_count yourself. Both counts ship in totals for exactly this reason.