Media audit: what to review in accounts, data, buying and contracts

A media audit is an independent review of how an advertiser plans, buys, measures and contracts its media, with the goal of verifying that the investment reaches the right audience, at the agreed price, with reliable data and evidence of results. In multinational companies, a media audit usually involves marketing, procurement, finance and legal.

In large companies, media is one of the biggest lines of marketing spend and one of the hardest to inspect. The money flows through agencies, platforms, technology vendors and media owners, each with its own dashboard and its own contract. Without a periodic review, the company knows how much it paid, but cannot say precisely what it bought or what effect that had.

What a media audit is, and what it is not

A media audit compares what was planned, contracted and paid with what was delivered and measured. It looks at account structure, the quality of conversion data, buying efficiency, inventory quality, contract terms and the evidence behind the budget split.

It is not a fee negotiation under another name. Agency fees are one item in scope, but cutting the fee without looking at everything else can make results worse. Nor is it an exercise in finding someone to blame. The most common causes of waste are structural: poorly defined goals, broken tracking, contracts that do not provide for data access. An audit that turns into a trial of the agency produces defensiveness, not learning.

It helps to separate two families of work. A financial and contract audit checks whether charges match the contract and what actually ran. A performance and operations audit checks whether media is well structured, well measured and well allocated. Many companies need both, with different teams and timelines.

When to run a media audit

• Before an agency review, so the brief describes the actual state of the accounts rather than perceptions about them.
• When a new CMO or head of media arrives and needs a baseline before changing strategy.
• When the budget grows significantly and leadership wants to know whether the current structure can absorb more investment without losing efficiency.
• When waste is suspected: costs rising without explanation, platform results that do not show up in sales, numbers that change depending on who is presenting.
• Periodically, as part of governance, even with no apparent problem. Contracts and platforms change faster than internal processes.

Media audit scopes

The scope should be chosen based on the decision the audit will support. Not every audit needs to cover everything, but the advertiser should know what was left out.

• Account and campaign structure: how accounts are organized, naming conventions, targeting, audience overlap, campaigns competing against each other in the same auction, and default settings nobody has reviewed.
• Tracking and conversion data quality: whether the conversions sent to platforms are the ones that matter to the business, whether there is duplication, whether consent is respected, and whether the numbers reconcile with CRM and sales.
• Buying efficiency and pricing: costs compared with history and with the plan, frequency, budget distribution across formats, and the weight of technology and intermediary fees relative to the amount that reaches the inventory.
• Inventory quality: brand safety (the suitability of the environment where the ad appears), invalid traffic and viewability.
• Contracts and transparency: remuneration, rebates, principal-based buying, data ownership, account access and audit rights.
• Allocation and incremental evidence: whether the budget split across channels rests on evidence of causal effect or on each platform's own attribution.

Tracking: the foundation that distorts everything else

Media platforms optimize for the signals they receive. If the configured conversion is a button click, the media learns to generate button clicks. If the same sale is sent twice, cost per sale shows up at half its real value. That is why the tracking review usually comes before performance analysis. It covers the list of events sent, the consent setup and a comparison with the sales source. The article on server-side tracking and Consent Mode details the architecture that reduces these losses.

Inventory quality: viewability and invalid traffic

The most widely used reference for viewability is the MRC viewable impression guidelines, from the US Media Rating Council. For display, an impression is viewable when at least 50% of its pixels are in the viewable area of the screen for one continuous second. For video, the criterion is 50% of pixels for two continuous seconds. The MRC also separates invalid traffic into general (GIVT), identified through lists and rules, and sophisticated (SIVT), which requires more advanced analysis.

The audit checks whether these metrics are measured by an independent tool, whether the contract sets minimum thresholds, and what happens when they are not met. Internationally, Trustworthy Accountability Group (TAG) seals, such as its anti-fraud and brand safety certifications, are used as criteria for choosing partners in the programmatic supply chain. The discussion of programmatic media and digital OOH goes deeper into buying criteria.

Contracts and transparency

In 2016, the ANA, the US Association of National Advertisers, published a study on media buying transparency conducted by K2 Intelligence. The work, limited to the US market, described rebates paid by media owners to agencies and transactions in which the agency buys media on its own account and resells it to the advertiser at a markup, known as principal-based buying. The study also found that many contracts contained clauses opting the advertiser into these transactions.

In Brazil, incentive plans paid by media owners to agencies are an established market practice, known as BV (a volume bonus). Law 12,232/2010, which governs how the public sector contracts advertising services, treats these plans as agency revenue and prohibits putting them ahead of the client's interests. For private advertisers, treatment depends on the contract. Global procurement teams should understand this difference before applying to Brazil a contract model designed for another market.

In the contract review, the audit answers objective questions:

• Who owns the ad accounts, the data and the audiences built with the advertiser's investment.
• Whether the advertiser has admin access to the accounts and to the verification tools.
• How rebates, bonus inventory and principal-based purchases are handled, and whether they require prior written approval.
• Whether the contract provides for audit rights, a document retention period and access to detailed delivery data.
• How technology, data and verification fees are charged and reported.

How a media audit works, step by step

• Defining the question and the scope: which decision the audit will support, and which channels, markets and periods are included.
• Access: read access to ad accounts, analytics, verification tools and the ad server, plus contracts and invoices.
• Data collection: exports of delivery, costs, conversions and sales for the period, using the same date and currency definitions.
• Interviews: marketing, media, procurement, finance, data and the agency itself, to understand goals, routines and constraints.
• Analysis: cross-checking plan, invoice, delivery and results, with evidence for each finding.
• Report: findings prioritized by financial impact and effort, separating verified fact from hypothesis.
• Action plan: owners, deadlines and the test that will confirm each hypothesis.

What a good media audit report contains

• An executive summary with the highest-impact findings and the amount at stake in each.
• The methodology, sources and limitations: what could not be verified, and why.
• Findings backed by reproducible evidence, such as queries, screenshots and data reconciliations.
• The distinction between confirmed problem, risk and opportunity.
• Recommendations with an owner, a deadline and a tracking metric.
• A testing agenda for the hypotheses the analysis cannot resolve on its own.

Hypothetical example: how much of the investment reaches a viewable impression

The following figures are illustrative and do not represent market or client data. An advertiser invests R$ 5 million a year in open programmatic. The audit shows that R$ 1.5 million goes to buying platform, data, verification and intermediary fees. R$ 3.5 million, or 70% of the total, reaches the inventory.

Of the impressions bought, 2% are classified as invalid traffic, and 60% of the valid ones meet the MRC viewability standard. The amount that reaches valid, viewable impressions is R$ 3.5 million multiplied by 0.98 and by 0.6, about R$ 2.06 million. The effective cost per thousand viewable impressions is much higher than the CPM shown in the dashboard.

The conclusion is not that the rest was wasted. Fees pay for services, and a non-viewable impression may have some effect. The finding is that comparisons across channels and partners should use cost per valid, viewable impression, and that the contract needs to spell out every fee. The action plan renegotiates the supply chain, reviews the site list and measures the effect with an incrementality test.

Allocation and incremental evidence

A well-structured, well-bought account can still be in the wrong channel. The audit checks whether the budget split rests on tests, on marketing mix models or on each platform's attribution, which tends to favor whoever is closest to the purchase. The article on incremental media measurement shows how to design these tests, and the discussion of media budget allocation shows how to turn the results into decisions.

Independence and conflicts of interest

The audit must be independent of whoever runs the media. An agency auditing its own accounts has an obvious conflict, and so does an auditor who later pitches for the account. Have this point declared before the engagement and require that findings be verifiable by third parties.

Independence also depends on access. An auditor who works from reports prepared by the agency sees what was selected. Direct access to the accounts and delivery data is a precondition for the audit to have value.

Common media audit mistakes

• Reducing the audit to a comparison of CPMs against market benchmarks with no source or context.
• Analyzing performance before checking that tracking is correct.
• Accepting exported reports instead of account access.
• Presenting hypotheses as facts and not stating what could not be verified.
• Delivering a report without an action plan, owners and deadlines.
• Treating the audit as a one-time event, without repeating the measurement to see whether the fixes worked.

Frequently asked questions about media audits

What is a media audit?

It is an independent review of how a company plans, buys, measures and contracts its media. It compares what was planned and paid with what was delivered and measured, and checks whether the budget split is backed by evidence of results. The end product is a report with findings and an action plan.

How long does a media audit take?

It depends on the scope, the number of channels and markets, and how quickly access is granted. A review focused on a set of accounts is faster than a review of contracts and the programmatic supply chain across several countries. Getting access granted is usually the biggest source of delay.

Who should commission a media audit?

The advertiser, not the agency being audited. In large companies, marketing usually leads, with procurement, finance and legal involved. The audit contract should guarantee confidentiality and direct access to the data.

Does a media audit replace an agency review?

No. The audit describes the state of the accounts and contracts. The agency review selects a partner. Doing the audit first makes the review more objective, because the brief starts from facts.

How often should you run a media audit?

There is no fixed rule. Many companies run a broad review when leadership, the agency or the level of investment changes, and smaller tracking and inventory reviews throughout the year.

If you already invest in media, the starting point can be an audit of your accounts: explore our Media practice and the discussion of media budget allocation.