A good agency report lets you verify three things: what was spent, what it produced, and what the agency was paid. Almost every report handles the first two. The third is where reporting reliably stops, and the industry’s own literature explains why.

This is not a claim that your agency is doing something wrong. It is that the standard reporting format was never designed to answer the third question, and the documented practices that make it worth asking sit at a level your contract may not reach.

This page covers what to require, what the transparency literature actually found, and what both sides of that argument said.

The three questions a report should answer

Structure the requirement this way and most format arguments disappear.

What was spent. By platform, by campaign, by period. Reconciled to the platform’s own interface, not retyped into a slide. If you cannot match the report to what the ad account says, the report is a narrative.

What it produced. Not impressions and clicks. Leads that entered your CRM, meetings held, opportunities created. The metric should belong to your business, not to the platform.

What the agency was paid. The fee, the basis on which it was calculated, and any other consideration received in connection with your spend. This is the question that distinguishes a report from a scorecard.

Why the third one matters even in a clean relationship. Because you cannot judge whether a media plan was built for your outcomes or for the supplier’s economics unless you know how the supplier is compensated. That is true of any intermediary and it is not an accusation.

And a fourth item that is not a question but a hygiene requirement. The definitions. Which attribution window, which conversion counting setting, which attribution model, and which days are still provisional. Without them, month-over-month comparisons are not comparisons.

What the transparency study found

The reference document in this field, with its sample and its caveats.

The study. Conducted 20 October 2015 to 31 May 2016, commissioned by the US advertiser association, carried out by an investigations firm.

The sample, verbatim. Based on information compiled from interviews with 150 individual sources, including marketers, media suppliers, ad tech vendors, current and former agency professionals, trade association executives, consultants, attorneys and others, all granted anonymity.

The response rate, which is itself a finding. An additional 131 interviews were requested: 61 declined, 70 failed to respond. Five of the six major agency holding companies declined formal requests to make any current executives available.

Who was actually in scope. Of the 150, 117 were directly involved in US media buying. Of those, 59 reported direct experience of non-transparent practices: 34 on rebates, 33 on principal transactions.

On rebates, verbatim. Cash rebates from media companies were provided to agencies with payments based on the amount spent on media, and advertisers interviewed indicated they did not receive rebates or were unaware of any rebates being returned.

The scale. Of 41 sources reporting that rebate deals occur, 34 reported indications they were not disclosed, not passed through, or demanded by agencies, in amounts ranging from 1.67% to approximately 20% of aggregate media spending.

And the mechanism that hides them. Rebates structured as service agreements, in which suppliers paid agencies for non-media services often tied to spend volume, which sources described as being used to obscure what was essentially a rebate.

Sample composition and principal findings of the 2016 United States media transparency studySummary of the sample composition and principal findings of the independent study of media transparency in the United States advertising industry, commissioned by the advertiser association and conducted by an investigations firm between the twentieth of October two thousand and fifteen and the thirty-first of May two thousand and sixteen. The study was based on information compiled from interviews with one hundred and fifty individual sources including marketers, media suppliers, advertising technology vendors, current and former advertising and media agency professionals, trade association executives, industry consultants, attorneys, barter company employees and post-production professionals, all of whom were granted anonymity such that the commissioning association is unaware of their identities. An additional one hundred and thirty-one interviews were requested, of which sixty-one declined and seventy failed to respond, and five of the six major agency holding companies and their affiliated companies declined formal requests to make any of their current executives available for interview. Of the one hundred and fifty sources, one hundred and seventeen were directly involved in media buying in the United States, and of those one hundred and seventeen, fifty-nine reported direct experience of non-transparent practices, comprising thirty-four concerning rebates and thirty-three concerning principal transactions, with possible overlap between those categories. On rebates specifically, forty-one sources reported that media rebate arrangements occur in the United States market, and of those forty-one, thirty-four reported indications that the rebates were not disclosed to advertisers, were not passed through to advertisers, or were demanded by agencies, in amounts ranging from one point six seven percent to approximately twenty percent of aggregate media spending depending on the arrangement. The investigations firm stated that the work was designed to shed light on certain non-transparent practices rather than constituting an investigation or an audit.The 2016 study, sample and findings20 October 2015 to 31 May 2016. All sources anonymous.The sampleSources interviewed150Directly in US media buying117Reported direct experience5934 on rebates, 33 on principal transactionsWho would not speakFurther interviews requested131Declined61No response705 of 6 major holding companies declinedOn rebates, verbatim”Advertisers interviewed… indicated they did not receive rebates or were unaware of any rebatesbeing returned.” Of 41 sources reporting rebate deals, 34 saw them undisclosed or not passed through.Rebate scale1.67% to approximately 20% of aggregate spendPrincipal markupsapproximately 30% to 90%The investigators’ own framing”a study designed to shed light on certain non-transparent practices… not an investigation or an audit”
Five of the six major holding companies declined to make executives available. That refusal is part of the finding. Source : ANA / K2 Intelligence, An Independent Study of Media Transparency in the U.S. Advertising Industry (2016)

What the agencies said back

Citing one side of a contested study and calling it settled would be exactly the failure this series is supposed to avoid.

The agency association’s response, verbatim. That the immense shortcomings of the report, anonymous, inconclusive, and one-sided, undercut the integrity of its findings.

On process, verbatim. That a healthy and constructive debate about media buying can only happen with a bipartisan, engaged, industry-wide approach, and that this is precisely the opposite of what the advertiser association pursued.

Their central request, verbatim. That the association make available to specific agencies, on a confidential basis, all of the materials related to them, because without an opportunity to assess and address the veracity of the information, sweeping allegations will continue to drive attention-grabbing headlines.

Individual holding company responses. One called it an unfair and unwarranted attack on the entire industry. Another called it disappointing, stating that its outside counsel had requested specific evidence and that none was provided.

How to weigh both sides fairly. The anonymity objection is genuine: anonymous sourcing cannot be independently checked. The refusal to participate is also genuine: five of six holding companies declined to make executives available, which is one reason the sourcing ended up anonymous.

What survives the argument. That practices of this kind exist and are documented in enough detail to be describable. Not that any specific agency engaged in them, which the study never claimed and explicitly disclaimed.

And what that means for you. The right response is not suspicion of your agency. It is a contract that makes the question answerable, so that neither of you has to rely on trust for something that can simply be written down.

What an audit can and cannot reach

The British advertiser association publishes audit guidance, and it is unusually candid about its own limits.

What an audit covers, verbatim. That it is an audit to ensure the agency is complying with the agreed financial and legal terms of the agreement, particularly relating to fees and billings, and that any discounts, agency trading benefits and balances are being returned to the client.

Recommended frequency. On average, annually for larger spending markets, every two years for smaller ones, plus an exit audit at the end of any contract.

On auditor independence, verbatim. That most agency groups now do not allow auditors to perform their services if their remuneration is based on a percentage of recovery, as this questions the auditor’s ability to be impartial and objective.

The limit, stated plainly, verbatim. That access to vendor deal terms will be severely restricted due to confidentiality, as agencies will not share potentially commercially sensitive information directly with advertisers.

And the moving-target problem, verbatim. That persistent barriers have included the use of proprietary or inventory media, restricting data access, the changing form of trading benefits and absence of audit rights, and that as advertisers amended contracts to mitigate risks, agencies changed their trading terms with vendors, created new terminologies for practices and moved the goal-posts.

The structural point underneath all of it. The practices described sit at holding company level. An audit right against the local entity you contracted with cannot see them, which is why the audit-rights dispute between the two associations was specifically about extending audits to the holding company.

The agency association’s rebuttal and the documented limits of a contract compliance auditPresentation of the agency association’s rebuttal to the media transparency study alongside the documented limits of a contract compliance audit as published by the British advertiser association. The agency association responded that the immense shortcomings of the report, being anonymous, inconclusive and one-sided, undercut the integrity of its findings; that a healthy and constructive debate about media buying can only occur through a bipartisan, engaged, industry-wide approach which is precisely the opposite of what the advertiser association pursued; and that the association should make available to specific agencies on a confidential basis all materials relating to them, because without an opportunity for agencies to assess and address the veracity of the information provided, sweeping allegations will continue to drive attention-grabbing headlines. Individual holding companies described the report as an unfair and unwarranted attack on the entire industry, and as disappointing, one noting that its outside counsel had requested specific evidence and received none. Both objections carry weight: anonymous sourcing cannot be independently verified, and equally the refusal of five of six holding companies to make executives available is one reason the sourcing became anonymous. On audits, the British advertiser association’s guidance states that an audit ensures the agency is complying with the agreed financial and legal terms of the agreement, particularly relating to fees and billings, and that discounts, agency trading benefits and balances are being returned to the client; recommends annual audits for larger spending markets, biennial for smaller, plus an exit audit at contract termination; notes that most agency groups now prohibit auditors remunerated on a percentage of recovery basis because this questions impartiality; and states plainly that access to vendor deal terms will be severely restricted due to confidentiality since agencies will not share commercially sensitive information directly with advertisers.Both sides, and the limit both live withThe agency association’s objection”anonymous, inconclusive, and one-sided”Asked for the underlying materials to be sharedconfidentially with named agencies.One holding company: “unfair and an unwarrantedattack on the entire industry.”And the counterweightAnonymous sourcing cannot be checked.And five of six holding companies declined tomake executives available, which is one reasonthe sourcing became anonymous.Both objections are real.What an audit reaches, and where it stopsReachesCompliance with agreed financial and legalterms. Fees, billings, discounts returned.Does not reach”access to vendor deal terms will be severelyrestricted due to confidentiality”And the moving-target problem, in the guidance’s own words”as advertisers have amended their contracts… so agencies have changed their trading terms withvendors, created new terminologies for practices and moved the goal-posts.”
The anonymity objection is real. So is the refusal to participate that produced it. The vendor terms stay closed either way. Source : 4A's response; ISBA Agency Contract Compliance Audit Guidelines (2020)

The verification ceiling, measured

One study tried to trace the money end to end under the best possible conditions. Its result sets the realistic ceiling on any reporting requirement.

The setup. Fifteen months of work, more than fifty participating organisations including advertisers, agencies, demand and supply platforms and publishers, all consenting, with an accounting firm as the trusted intermediary.

The matching result, verbatim. From 267 million impressions served from study advertisers to study publishers, 31 million, 12%, were successfully matched. The rest could not be mapped due to low data quality.

The money, verbatim. Publishers received half of advertiser spend. 15% of advertiser spend, the unknown delta, representing around a third of supply chain costs, could not be attributed.

What that establishes. Under the most favourable conditions anyone has assembled, with everyone cooperating and a professional intermediary, 88% of impressions could not be traced end to end.

Why that matters for your report. It bounds what any reporting requirement can honestly promise. A contract clause demanding full traceability of programmatic spend is asking for something that has not been achieved in a controlled study.

What to require instead. Traceability where it is achievable, meaning platform-direct buying reconciled to platform invoices, and disclosure where it is not, meaning a stated declaration of any principal or inventory media in the plan.

And the honest framing for your own reporting, if you are the agency. Say which parts are verifiable and which are not. A supplier who volunteers the limit is more credible than one who implies there is none.

Measured ceiling on end to end traceability of programmatic advertising spendPresentation of the measured ceiling on end to end traceability of programmatic advertising expenditure, established by a supply chain transparency study conducted over fifteen months with more than fifty participating organisations comprising advertisers, agencies, demand side platforms, supply side platforms and publishers, all participating voluntarily, with a professional accounting firm acting as trusted intermediary. From two hundred and sixty-seven million impressions served from participating advertisers to participating publishers, thirty-one million, representing twelve percent, were successfully matched from end to end, with the remainder unable to be mapped due to low data quality. On the financial side, publishers received half of advertiser expenditure, while fifteen percent of advertiser expenditure, described as the unknown delta and representing approximately one third of supply chain costs, could not be attributed to any party. The significance is that under the most favourable conditions anyone has assembled, with all participants cooperating voluntarily and a professional intermediary conducting the matching, eighty-eight percent of impressions could not be traced from advertiser to publisher. This bounds what any reporting requirement can honestly promise, since a contractual clause demanding full traceability of programmatic expenditure requests something that has not been achieved even in a controlled study with willing participants. The appropriate substitute is to require traceability where it is achievable, meaning platform-direct buying reconciled against platform invoices, and disclosure where it is not, meaning a stated declaration of any principal or inventory media included in the plan.The ceiling, measured15 months, 50+ organisations, all consenting, accounting firm in the middle.Impressions served267MSuccessfully matched end to end31M · 12%“15% of advertiser spend… could not be attributed”Described as the unknown delta, around a third of supply chain costs.88% of impressions could not be traced, with everybody helpingThat is the realistic ceiling on any traceability clause you might write.Require where achievablePlatform-direct buying, reconciled to invoices.Disclose where it is notA stated declaration of principal or inventory media.
Everyone cooperating, an accounting firm in the middle, fifteen months: 12% of impressions matched. Source : ISBA / AOP / PwC Programmatic Supply Chain Transparency Study (2020)

One metric to stop putting at the top of reports

A small, specific correction that comes up constantly.

What it is. Optimization score, presented in many agency reports as a headline number, often with a target attached.

What the platform says it is, verbatim. An estimate of how well your Google Ads account is set to perform, on a scale of 0 to 100%, with 100% meaning the account can perform at its full potential.

What that makes it. A prediction about the account’s configuration, derived from the platform’s own pending recommendations. It is not a measurement of results.

What the platform claims for acting on it. That regularly reviewing and applying recommendations can help improve performance. Not that it will.

The circularity worth noticing. The score rises when you apply the recommendations that the score is calculated from. Moving it is not evidence that anything improved for your business.

Where it belongs. In the diagnostic section, as a list of pending recommendations to accept or decline with reasons. Not as a headline, and never as a contractual target.

Why optimization score does not belong at the top of an agency reportExplanation of why the optimization score metric does not belong as a headline figure in an advertising agency report. The platform defines optimization score as an estimate of how well the advertiser’s account is set to perform, scored from zero to one hundred percent, with one hundred percent meaning the account can perform at its full potential, calculated from statistics, settings and account status together with available recommendations and their relevant impact. This makes it a prediction about the account’s configuration derived from the platform’s own pending recommendations, rather than a measurement of business results achieved. Regarding the effect of acting upon it, the platform states that regularly reviewing and applying recommendations can help improve campaign performance, using conditional language rather than asserting certainty, and notes that recommendations display how much the optimization score will be impacted when applied, which refers to movement in the score itself rather than to guaranteed improvements in campaign performance. A circularity therefore exists: the score rises when the advertiser applies the recommendations from which the score is calculated, so moving the score is not evidence that anything improved for the advertiser’s business. The appropriate placement for this metric is within the diagnostic section of a report, presented as a list of pending recommendations to be accepted or declined with reasons recorded, rather than as a headline figure and never as a contractual performance target.One number to move out of the headlineWhat the platform says it is, verbatim”Optimization score is an estimate of how well your Google Ads account is set to perform.”Scores run 0-100%. Applying recommendations “can help improve” performance.The circularityIt rises when you apply the recommendationsit is calculated from.Where it belongsThe diagnostic section: pending recommendations,accepted or declined, with reasons.It is a prediction about configuration, not a measurement of resultsMoving it is not evidence that anything improved for your business.And never a contractual target. A supplier can reach 100% without selling you anything.
It is an estimate of configuration, calculated from the recommendations it asks you to apply. Source : Google Ads Help, About optimization score (2026)

What to put in the contract

Six clauses, none of which is adversarial, all of which make the questions answerable.

An audit right that names the holding company, not only the entity you contracted with. That is the specific gap the association dispute was about.

A stated remuneration model. Fee basis, and a declaration of any other consideration received in connection with your spend.

Disclosure of principal or inventory media. Whether any media is being resold to you rather than bought on your behalf, stated per plan.

Platform access in your own name, so that reported spend can be reconciled to the platform’s own interface without going through anybody.

Reporting definitions on the face of the report. Attribution window, counting setting, model, and provisional period.

And an exit audit, contracted in advance. It is recommended practice, it is far easier to agree at signature than at termination, and it is the moment when it matters most.

Six contract clauses that make agency remuneration and media buying questions answerableSix contract clauses recommended for an advertiser-agency agreement, none of which presupposes bad faith and all of which render the relevant questions answerable. The first is an audit right that explicitly names the holding company rather than only the contracting entity, which addresses the specific gap identified in the public dispute between the advertiser and agency associations, since the practices documented in the transparency study frequently occur at holding company level where an audit right against a local subsidiary cannot reach. The second is a stated remuneration model specifying the fee basis together with a declaration of any other consideration received in connection with the client’s expenditure. The third is disclosure of principal or inventory media, meaning a per-plan statement of whether any media is being resold to the client rather than purchased on the client’s behalf, since principal transaction markups in the study ranged from approximately thirty to ninety percent. The fourth is platform access held in the advertiser’s own name, so that reported expenditure can be reconciled directly against the advertising platform’s own interface without intermediation. The fifth is that reporting definitions appear on the face of the report itself, specifically the attribution window, the conversion counting setting, the attribution model in use, and which recent period remains provisional, without which month to month comparisons are not genuine comparisons. The sixth is an exit audit agreed in advance at the point of signature, which the British advertiser association recommends as standard practice, which is substantially easier to negotiate at the beginning of a relationship than at its termination, and which applies at precisely the moment when it carries the most value.Six clauses, none of them adversarial1. An audit right that names the holding companyThe specific gap the industry dispute was about. A local-entity audit cannot see holding-level practice.2. A stated remuneration modelFee basis, plus any other consideration received.3. Principal or inventory media disclosedPer plan. Resold to you, or bought for you?4. Platform access in your own nameSo spend reconciles without going through anyone.5. Definitions on the report itselfWindow, counting setting, model, provisional days.6. An exit audit, agreed at signatureRecommended practice, far easier to agree now than at termination, and most valuable exactly then.None of this assumes your agency is doing anything wrongIt removes the need to rely on trust for something that can simply be written down.
The holding company clause is the one the industry dispute was actually about. Source : ANA recommendations and ISBA audit guidance (2026)

Where to go next

You are choosing an agency. Choosing a B2B acquisition agency.

You are about to switch. Audit your ad account before switching.

You want to know how long to give them. How long before judging an agency.

You are weighing bringing it in-house. In-house vs outsourced media buying.

You want to know where programmatic money goes. Programmatic advertising.

Your dashboard and your platforms disagree. B2B marketing dashboard blind spots.

In short

  • A report should let you verify three things: what was spent, what it produced in business terms, and what the agency was paid. The third is usually absent.
  • The 2016 study interviewed 150 sources; of the 117 directly in US media buying, 59 reported direct experience of non-transparent practices.
  • 34 of 41 sources reporting rebate deals said they were undisclosed, not passed through, or demanded, at 1.67% to approximately 20% of aggregate spend.
  • Principal transaction markups ranged from approximately 30% to 90%.
  • Five of six major holding companies declined to make executives available, which is both a finding and the reason the sourcing is anonymous.
  • The agency association rejected it as anonymous, inconclusive and one-sided, and asked for the materials to respond to. Both objections have force.
  • Audits cannot reach vendor deal terms. The British guidance says access will be severely restricted due to confidentiality.
  • And full traceability is not achievable: 12% of impressions matched end to end in a study where everyone cooperated.

Write the clauses now, while nobody is annoyed. Book a diagnostic, or see how we approach B2B growth.