How do you brief a new agency on what the last one did?

Take a made-up UK accountancy practice, with twelve people and a managing partner who has just ended an engagement after two years. She drafts a long email to the incoming agency in an evening. It says the last agency was slow and the leads were poor. The new agency reads it, nods and starts from scratch, because the email contains nothing it can check. Search Console, the one place the practice could have shown which pages earned enquiries, holds only about sixteen months of history, so the evidence was already running out. Complaints are not a brief. What follows is the shorter document a practice can write in an afternoon, built from records that exist whether or not the old agency replies.

Why the new agency needs the brief more than you do

The firm already knows the engagement went badly, but the new agency knows nothing about it and will fill the gap with assumptions. Without a brief it will use the old agency's reports and the firm's mood in the first call. None of those is a reliable account of what happened. A brief fixes that by giving the incoming agency the facts first, in an order it can test.

There is also an incentive problem that has nothing to do with honesty. A departing agency has little reason to write a careful history of its own weaknesses, and the firm should not ask it to. Our guide to what to reclaim when an engagement ends covers what to ask the old agency for. This page covers the part that cannot be outsourced to it, which is what the firm tells the next one.

What each record can tell the new agency, and for how long

Some of the history on the canvas has a clock on it, and the clock should decide the order of work. Google introduced the Search Console performance report with sixteen months of data, and its help page describes the report as opening on a short default range that the user widens. A UK practice that waits a year to brief anyone will find the first months of the old engagement gone from the one report that shows which search queries brought visitors. Export the report now, as a file, before anything else.

Analytics has a similar limit. Google's data retention page says a standard property can keep event-level data for two months or fourteen, and the setting is the firm's to check in the Admin area. We have not verified what any particular property is set to, so look rather than assume. Aggregate reports behave differently from the detailed explorations, which is a question for the new agency to answer in its readback.

Google Ads is the kinder case. As we noted in the reclaim guide, Google's page about unlinking accounts says the advertiser account keeps its own campaign history when a manager is unlinked. The structure of what ran is therefore still in the firm's account, and the new agency can read it directly once it has access.

Start the brief with the firm's own count

Row 3 of the canvas is the one that decides whether the rest can be trusted, so write it first. Platform dashboards report what the platform recorded, and an agency's monthly report reports what the agency chose to show. The firm's own enquiry log, kept by whoever answers the phone and the inbox, is the only count that neither of them produced. Put it beside the platform figure for the same month and record the gap, even when the gap is small.

If the practice has no log, say so in the brief rather than reconstructing one from memory. A new agency that is told there is no independent count can make a log the first thing it sets up, which is a better start than inheriting a number nobody could check. The same goes for a firm that cannot say which enquiries became clients: that is a gap in the record, and naming it is part of the brief.

Keep records and recollections on separate lines

Write each line of the brief as either a record, which has a date and a place, or a recollection, which has neither. A record says that the monthly report for March listed forty enquiries and the firm's own log shows twenty-six. A recollection says the leads dropped off sometime in the spring. Both are useful, but only the first can be tested by someone who was not there.

Give the recollections their own short section at the end, and do not let them carry the argument. The new agency will read that section as context and the rest as fact, which is exactly the weighting the firm wants. The practical effect is that a grievance with no date on it stays in the brief as a grievance, not as a finding. It also stops the managing partner from overstating a case that the records would have made more modestly and more credibly.

The first-week readback

Ask the new agency to write the brief back to the firm in its own words before it proposes anything. A readback is short, one page, and it is the cheapest test the firm has of whether the agency understood what it was told. It also shows early whether the agency is willing to say what it does not know.

Two lines from a made-up brief

The difference between a record and a recollection is one clause, and it decides how the line is used. This is a hypothetical, not a client. A recruitment agency writes: “The March report gave thirty-one enquiries from search; the firm's own log shows nineteen. Source: the March PDF and the log, both attached.” That is a record, and the new agency can start by reconciling the two numbers. The same agency also writes: “We felt the old team stopped replying after Christmas.” That is a recollection, and it goes under its own heading. The first line gives the agency a task. The second tells it how the firm felt, which it should know but not act on.

When not to brief yet

Do not brief a new agency until the firm holds the accounts the brief describes. If the Search Console and Analytics properties still sit under the old agency's logins, the five answers cannot be read, and the brief becomes a list of things the firm hopes are true. Our earlier piece on whether it is cheaper to fix the agency or replace it counts the months a switch costs before it delivers anything, and a brief written on a guess adds to them.

Do not use the brief to settle a score, either. If the firm wants a refund or legal advice about a contract, that belongs in a separate message to a solicitor. And a UK firm that cannot yet say what it wants from marketing is not ready to hire anyone, however good the history. Start with the outcome, then look at how we introduce one specialist. For the firms we serve, see accountancy practices, recruitment agencies, tax advisory and financial advice firms.