The single most useful thing you can do in an agency pitch is ask what the reported return is measured against. An agency that answers with total revenue and total spend for the whole account is measuring the thing you actually care about. One that answers with the platform's own number is showing you a figure the platform has an incentive to flatter, and the gap between those two is often the entire difference between the agencies you are comparing.
Here are the six questions worth asking, in the order that finds the problem fastest.
One: what is the number measured against?
Google reports conversions it believes it caused, on its own attribution window, including branded searches from people who were already coming. Your bank does not. Ask for account level spend against total store revenue for the same weeks, and ask what share of the conversions were branded. A good agency has already separated those, because the gap between the platform and the bank is the first thing worth fixing.
Two: who actually touches the account?
The person in the pitch is often not the person in the account. Ask directly who logs in, how many accounts that person carries, and whether any of the work is subcontracted. There is no right answer to the number, but there is a right kind of answer: a specific one.
Ask what they would change in the first month. An agency that cannot answer before seeing the account is guessing, and one that answers with a template is worse.
Three: what do they do before they touch bidding?
Almost every real gain in a Google account sits upstream of bids: tracking that measures the right event, a feed that lets the whole catalogue compete, a structure that does not have branded and non branded fighting from one budget. An agency that opens with bid strategy is optimising the last five percent of the problem, and the answer to this question tells you which kind you are hiring.
Four: what happens to the account if we stop working together?
The account, the conversion tags, the Merchant Center and the data should be yours, in your own Google account, with the agency holding access rather than ownership. Ask it plainly. An agency that builds inside its own manager account and hands you nothing at the end has made leaving expensive on purpose.
Five: what will you tell me when it is not working?
Everything underperforms at some point. What you are hiring is the reporting on the bad month, not the good one. Ask what the last account they lost looked like and why, and listen for whether the answer contains a mistake they made. An agency that has never made one has not been running accounts long enough, or is not telling you.
Six: what is the actual scope?
Google Ads performance is limited by the landing page more often than by the account, so an agency that will not touch the site is capped at whatever the site converts at today. Ask whether the scope includes the page the traffic lands on, and if not, who is doing that. The same applies to what you are actually paying for, which is worth reading before the first call.
What we do with it
We answer all six in writing before anything is signed, on your account rather than in the abstract, and the first thing we look at is measurement rather than bidding. What that looks like in practice is on the how we work page, and the channel itself is on the Google Ads page.