How periods are calculated

A period's number is always recomputed from the underlying counts, never averaged from smaller percentages.

Averaging percentages misleads whenever weeks carry different volumes: a quiet week would count as much as a busy one. So we sum the numerators and denominators across the period first, then divide once.

Metrics that only exist when you are mentioned, such as Position, Prominence, and Sentiment, carry their own sample counts through every calculation, and whenever a denominator is zero we show n/a instead of a fabricated 0.