The Advertising Waste Diagnostic
Find the advertising spend that is not buying customers, and know which part of that claim you can defend. This is the complete system in one place: the checklist, the worksheets, the finding format, and the exact prompts, so you can run it on your own account this week.
Two words carry the whole method. A conversion is whatever the platform counts as a result: a form filled, a call, a purchase.Attribution is the platform’s rule for which ad gets the credit for it. Neither is a customer, and you do not need to know anything else about either to use this. You need one month of platform exports, the same month out of whatever system holds your customers, and a willingness to let the second one overrule the first.
What you are looking for
Four kinds of wasted spend, different enough that one word for all of them is the main reason audits go wrong. Every dollar you question ends up in exactly one of these, and the label decides what you are allowed to do about it. Throughout, a slice is any cut of the spend you can name and put a dollar figure on: a campaign, a search term, a city, an hour, a placement, a network.
The output is not a percentage. It is a short list of findings, each carrying the rule that condemned it, plus one honest number for the spend nobody can see, plus one test that would settle the largest remaining question.
Name the decision before you start, because it changes what counts as a finding. Deciding whether to keep spending at all is a different audit from deciding which of two channels gets next quarter’s budget, which is different again from deciding whether the account is worth handing to someone else. An audit with no decision attached is an inspection, and inspections get filed.
Pick one month
Recent enough that the customers are still identifiable, old enough that the slow ones have closed. For most businesses that is the month before last.
Run every step below on that single month. One period keeps the arithmetic honest: the same denominator under every finding, and no quiet mixing of a good month’s spend with a bad month’s outcomes. Annualizing anything you find is a separate claim, made afterwards, with the assumption that the month was typical written next to it.
Evidence checklist
Pull all of it before you read any of it. Reading as you export is how the first interesting row becomes the conclusion.
From each platform
- Spend and conversions by campaign and by day, with the conversion action named and its attribution rule written beside it
- The conversion action inventory: which actions exist, which are primary, which are included in account-level goals, how each is counted, what value each carries, whether the tag is firing
- Search terms by cost, with the triggering keyword on each row
- Performance by network, so Search Partners and Display expansion are separable
- Geography by matched location, hour of day, and device
- On Meta: placement, frequency, CPM, click-through and conversion rate by creative and by ad set
- Campaign and ad-set inventory: objectives, conversion events, audience definitions, daily budgets
- Performance Max (PMax) search terms, compared against your Search terms
From the business
- Every lead, order, booking, or call in that month, from wherever the truth lives: CRM, order system, calendar, phone log, bank
- A source or campaign field where one exists, and a timestamp regardless
- The status each record reached: contacted, qualified, booked, sold, refunded
- Revenue, and contribution margin if you have it
- What one customer is worth after the cost of serving them. Without this, cheap and expensive are labels rather than judgments
- The written definition of a qualified lead, owned by whoever carries the consequence of being wrong about it
- How fast inquiries get answered, by whom, and how many attempts each one gets
- Whether the business could serve more work this month if it arrived
- Anything that changed in the month and could move the numbers on its own: a site change, a price change, a holiday, a staffing gap, a new location
Getting your evidence into an assistant
The step nobody writes down, and the one that stops most people before they start.
Getting the files out
- Nearly every business system has an Export or Download button that produces a CSV or Excel file. In Google Ads and Meta Ads Manager the button is on every report screen; your CRM, order system, or booking calendar has one too.
- For email, you don’t need to export a mailbox. Open the thread that matters and copy the text, or forward it to yourself and copy it from there.
- If something won’t export, photograph the screen. These assistants read screenshots, and a legible screenshot of a report beats a description of it.
- If nothing exports at all, you can still run this by writing down what happened — as long as you stick to what you could check later. Dates, counts, amounts, who did what. Not your impression of how it went.
Which assistant, and how many chats
- ChatGPT, Claude, Gemini, and Copilot all work. You want one that accepts file uploads; the free tiers of ChatGPT and Claude do, with a daily cap on how much you can send.
- Keep the whole thing in one conversation. Upload your evidence at the start and send the prompts in order, so what you uploaded is still in front of it when you reach the later ones.
- Start a fresh chat when you move to a different process, month, or account. Mixing two sets of evidence in one conversation is the most common way these go wrong.
- If a long upload fails or the replies start drifting, send less at a time: one campaign, one month, one stage of the process.
Match the platform’s count to your records
First and non-negotiable. Until the platform’s count is compared against your own records, every other number in the account inherits an unknown error.
Match lead by lead and order by order, then walk each platform conversion down the ladder and write the number at every rung. One block per platform, because they cannot be added.
Watch which rung the numbers fall off, because one of them is not an advertising problem at all. A heavy drop between found in your records and a reachable person usually means inquiries are arriving and nobody is getting to them in time. No bid change fixes that, and no amount of better targeting survives it. When the reconciliation lands there, the work moves to how the business answers its phone, and the Operations Diagnostic is the better tool for it.
The definition of qualified belongs to whoever lives with the consequences of getting it wrong, which is rarely the person running the ads. Get it written down before you argue about lead quality, and date it. A definition that quietly moves month to month lets anyone improve lead quality by changing the label, and nobody can tell afterwards whether the advertising got better.
How to write up a finding
Every finding takes this shape. The fields are there because each one is a way audits go wrong when it is missing.
What to check, and in what order
Work down the cuts in this order. The first two decide whether the rest can be trusted, which is why tuning bids and audiences comes last on every experienced practitioner’s list.
Add it up
Every dollar of the month on exactly one line: the four kinds of waste, plus a fifth line for the spend you matched to customers. Each line carries its criterion. This is the page the whole audit is for.
Design one test
For the largest thing the evidence cannot settle. One at a time, designed before anything switches off.
A quarter later, close the loop: the leakage you suspected, the change you made, the outcome you expected, the change you observed, and whether the saving was still there. Savings that move rather than persist are the most common way an audit gets remembered as a success it was not.
What the finished brief contains
Written so that the person who built the account, an accountant, or another analyst could check every line and disagree with it specifically.
- The reconciliation, one block per platform, with attribution rules labeled.
- The findings, each in the format above, ordered by size within their kind.
- The opaque number, stated plainly, with what produced it.
- The exclusions, meaning what you looked at and could not conclude anything about, and what would have been needed.
- One test, with its prediction written before it runs.
- The claims you are refusing to make, which is usually a total, an annualized figure, and any claim that the advertising created customers, which no holdout has earned yet.
That last item does more work than it looks like it should. An audit that names its own limits is the one a business owner can act on without wondering what was oversold.
The master prompt
Paste this into any AI assistant along with your exports. It runs the whole method in order and will not hand you a percentage.
I want you to help me audit my advertising spend. Your job is not to optimize my account or recommend tactics. Your job is to work out which dollars are not buying customers, and to be exact about how confident we can be for each one. I will give you exports: platform spend and conversions, various performance cuts, and records from my own system of record (CRM, orders, bookings, or calls) for the same month. Work through these stages, in order, and do not skip ahead: 1. INVENTORY THE EVIDENCE List what I gave you and what is missing. For anything missing, say whether it exists and I did not send it, or whether the platform does not publish it at all. Do not proceed as though a missing report is a zero. 2. RECONCILE For each platform, match reported conversions against my own records and walk them down this ladder: reported, found in my records, a reachable person, qualified, became a customer, revenue. Label every number with the rule that produced it. Never add figures from two platforms together. Say which matches are certain, which are probable, and which you cannot make. 3. CLASSIFY Put every questionable dollar in exactly one bucket: VISIBLE - directly observed in an export I gave you. MIS-MEASURED - counted as a result I cannot find in my records. OPAQUE - the platform does not disclose enough to classify it. CANNIBALISTIC - credit for demand that likely existed anyway. Always mark this one as unsettled. Where one finding straddles two buckets, split its dollars and cite the same finding on both lines. Cite the specific rows that put each dollar where you put it. 4. SIZE AND STATE THE CRITERION For each finding: the signal, the evidence, the criterion, the kind, the size in dollars for this month, and the move. Write the criterion as a sentence the person who built this account could argue with. If you cannot write that sentence, it is not a finding yet. 5. CHALLENGE YOURSELF For each finding: what evidence contradicts it, what else could explain the pattern, and what I would need to pull to confirm it. Flag every slice where the conversion count is too low to support a conclusion and leave those unclassified. 6. DESIGN ONE TEST For the largest thing the evidence cannot settle, propose a single holdout: what stops, where, what stays on as a comparable control, which outcome from my own records we measure, the prediction if the spend is incremental (creating customers who would otherwise not have come), how long, and what result would mean we were wrong. Work out whether my conversion volume can support it, using roughly 16 divided by the square of the fractional difference we want to detect as the outcomes needed per group, and say so if it cannot. 7. WRITE THE BRIEF The reconciliation, the findings ordered by size within their kind, the opaque number, what you could not conclude anything about, the test, and the claims you are refusing to make. Rules throughout: Never give me a single percentage of spend wasted. Do not call a cost per lead high or low unless I have told you what a customer is worth after the cost of serving them. Do not call a lead qualified unless I have given you the business's own written definition of the word. If the evidence shows inquiries arriving and not being reached, say plainly that the binding problem is outside the ad account. Never quote an industry waste statistic. If a number comes from outside my data, state its universe, its denominator, its failure definition, whether it was observed or modeled, and whether whoever published it sells the remedy. Never invent a number that is not in my exports. Do not treat a platform's conversion count as a customer. Do not treat absence of evidence as evidence of good spend, or as evidence of waste. Optimization advice comes last, and only for findings that survived stage 5. It is fine, and often correct, to conclude that the evidence cannot settle something.
Run this and you will know three things most advertisers never find out: how far the platform’s count sits from your own records, which of your spend is failing a rule you can state out loud, and how much of the account nobody can see at all. The fourth thing, whether the advertising is creating customers who would otherwise have stayed away, takes one test and a quarter of patience.
