Start with the question

Return on ad spend describes reported revenue relative to advertising spend. It does not describe every cost of making and delivering a sale. Before using it as a target, decide which decision it needs to inform: allocating a test budget, acquiring new customers or understanding the economics of an offer.

Put the missing context beside it

Place the ratio alongside the definitions that matter to the business: new versus returning customers, product margin, fulfilment cost, returns and the chosen attribution window. Different reporting systems can credit the same sale differently. A dashboard becomes more useful when those limitations are visible.

Choose a consistent review rhythm

Agree the source, the reporting window and the action threshold before reviewing the campaign. A short-term signal can help identify a question, but it should not be presented as proof of a long-term outcome. Keep the commercial context in view and use the review to decide what needs more evidence.

A good report leaves the team with a clearer next step, including when that step is to wait, investigate or stop.