What you need to compare two advertising periods

A practical sequence

1. Fix calendar boundaries, time zone and attribution window. Allow cohorts a comparable amount of time to mature.
2. List changes in spend, prices, availability, channels, pages and lead definitions. Separate business changes from campaign edits.
3. Compare the same unit: enquiries to enquiries, accepted leads to accepted leads. Show the absolute base next to relative change.
4. Record missing data and delayed outcomes. If periods remain materially different, present them side by side without a causal claim.

The decision to take away

A useful report may conclude that the periods are not yet comparable. That is more actionable than an unexplained percentage.

Sources and review date

Sources read on: 2026-09-11. A source review is not an audit of the agency’s systems.

• www.impressiondigital.com/our-work/norse-atlantic-airways-strategy/ ↗