AgencyAuditChecklist

How to Audit Your Agency’s Principal Media Practices: A 10-Point Checklist

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2026-01-29

8 min read

Practical 10-point audit to force placement transparency, verify inventory quality, and reclaim wasted media spend.

Hook: Stop Losing Visibility—and Money—on Principal Media

If your media performance reports are full of aggregated line items, unexplained markups, or surprise placements on low-quality inventory, you are not alone. Marketing leaders in 2026 face tightened margins, rising CTV spend, and a privacy-first ecosystem that makes undisclosed media practices more costly than ever. This 10-point audit checklist gives you a practical, contract-ready playbook to force placement transparency, verify inventory quality, and hold agencies accountable for media fees and outcomes.

What you’ll get in this guide

Actionable steps, document templates, KPI thresholds, and contract language you can drop into statements of work. Use this as a living principal media audit you run quarterly or before renewing any agency-managed spend.

Context: Why this matters in 2026

Recent industry shifts through late 2025 and early 2026 increased the need for placement-level transparency:

Privacy-first identity transitions and the maturation of alternative IDs (Unified ID variants, hashed solutions) changed targeting economics, pushing agencies to ration premium inventory.
CTV and programmatic video increased advertiser spend; programmatic CTV growth exceeded 20% YoY in many verticals in 2025—magnifying impact of poor placements.
Supply Path Optimization (SPO) and header-bidding complexity created more opacity around who captured what share of the CPM.
Regulatory and procurement scrutiny rose; advertisers that couldn't demonstrate placement-level oversight saw renegotiations and regulatory inquiries.

How to use this checklist

Run the checklist as a cross-functional exercise with procurement, legal, and the media team. Gather the agency’s:

Latest insertion orders (IOs), publisher line-items, and billing statements
Placement-level logs (CSV) with publisher domain and placement IDs
Third-party verification reports (IAS, DoubleVerify, Moat)
Contracts and SOWs that mention fees, rebates and audit rights

The 10-Point Principal Media Audit Checklist

1. Placement-Level Reporting: Demand the source CSV

What to request: A raw CSV that contains: date, publisher domain, placement ID, ad unit, impressions, clicks, media cost (gross), media cost (net), agency markup, IO ID.

Why it matters: Aggregated line items hide supply quality and markups. Placement-level data lets you filter by domain, viewability, and creative.

Red flags: Agency only provides rolled-up totals; CSV lacks publisher domain; cost columns are missing net vs gross splits.

Contract clause (sample): "Agency shall provide weekly placement-level data in CSV format including publisher domain, placement ID, impressions, clicks, gross media cost, net media cost, and markup. Client reserves the right to audit and reconcile these files quarterly."

2. Placement Transparency: Publisher & Deal IDs for Every Line

Verify every placement maps to a publisher domain and a deal type: PMP, Preferred, Open Exchange, Guaranteed. For programmatic buys request publisher seller.json entries when available.

KPIs & thresholds: At least 90% of programmatic spend should map to an identifiable publisher domain. More than 25% in "open exchange" for brand campaigns is a risk signal.

3. Fee Visibility: Gross vs Net and Agency Markups

What to request: For each placement, a clear gross CPM, net CPM (what the publisher received), and the agency markup expressed as a percentage and absolute amount.

Benchmarks: Typical transparent agency fee on programmatic can range 5–15% depending on services. Anything opaque or variable without disclosure is unacceptable.

Red flags: Fees reported as a single blended 'platform fee' with no reconciliation, or frequent unexplained rebates post-billing.

4. Inventory Quality: Viewability, Fraud, and Brand Safety

Ask for third-party verification reports and raw sample logs (bid responses or impression samples) for recent campaigns.

Viewability: Aim for display viewability >70%, video viewability >80% where practical.
Invalid Traffic (IVT): IVT should be <3% for most premium buys. Anything above 5% needs investigation.
Brand safety: Ask for contextual targeting logs and verification that content categories were enforced in each insertion order.

Sample request line: "Provide third-party verification detail by placement for the last 90 days including viewability, IVT rate, and contextual category compliance."

5. Supply Path Optimization (SPO) & Reseller Chains

Map the supply path for high-spend placements. Ask the agency to show the chain: SSP → reseller → exchange → publisher.

Why this matters: Long or opaque paths often mean multiple hidden resellers and additional markups. In 2026, many advertisers mandate short, identified SPO paths.

How to audit: Pull seller.json entries and request SSP IDs. If the chain includes more than one reseller between publisher and buyer, flag for renegotiation. Use system diagrams to visualise and present the chain to procurement and legal.

6. Placement Audits & Makegood Policies

Agencies should commit to makegoods (replacements, credits) for placements that miss agreed thresholds. Define thresholds and timing.

Sample policy clause: "If viewability for any placement falls below the agreed threshold by >20% or IVT >5%, Agency will provide makegoods within 30 days or credit the client for gross media spend proportionate to the shortfall."

7. Creative & Ad Serving Verification

Confirm which ad server is used and whether creative tags were verified for correct measurement. Misfired tags cause lost measurement and wasted spend.

Checklist items: creative tag list by placement, ad server logs, and proof of third-party impression pixels firing.

8. Contractual Audit Rights & Data Portability

Ensure the contract grants the client audit rights, access to raw telemetry for a defined period (12–24 months), and data portability in machine-readable formats.

Contract language (sample): "Client retains the right to inspect placement-level records and third-party verification reports. Agency must deliver all campaign telemetry in machine-readable CSV or Parquet within 7 business days of request."

9. Attribution & Reconciliation Practices

Demand clarity on which attribution model is used, how conversions map to placements, and whether agency-claimed conversions are reconcilable with your first-party analytics. Use an analytics playbook to structure reconciliation tests.

Audit step: Pick 10 high-value conversions and reconcile placement-level cost and conversions with your analytics platform. Unexplained discrepancies >10% require remediation.

10. Governance, Escalation, and Performance SLAs

Define a governance cadence and KPIs with escalation paths. SLAs should be measurable and tied to financial remedies where appropriate.

Monthly performance reviews with placement heatmaps
Quarterly SPO and publisher audits
Financial remedies or fee reductions for repeated non-compliance

Scoring Rubric: Turn the audit into a numeric score

Make the audit objective. Use a 0–2 score per item:

0 = Non-compliant / No evidence
1 = Partial compliance / Some data provided
2 = Fully compliant / Clear evidence & contractual backing

Score <12/20 = urgent remediation; 12–16 = action plan required; >16 = satisfactory but monitor quarterly.

Practical Templates & Snippets

Drop these into RFPs, IOs, and SOWs.

Minimum Data Delivery Template (CSV columns):

date
campaign_id
io_id
placement_id
publisher_domain
placement_type (display/video/CTV/native)
deal_type (PMP/Guaranteed/Open)
impressions
clicks
engagements
gross_media_cost
net_media_cost
agency_markup_amount
viewability_rate
ivt_rate
verification_provider

Demand Letter Snippet (for procurement): "Per our agreement, please provide placement-level CSVs and third-party verification files covering the last 90 days. Failure to provide full transparency will trigger the audit clause and may affect media fee payments."

Case Example: How an Audit Recovered 18% of Spend

In Q4 2025, a retail advertiser running a mix of programmatic display and CTV engaged an independent audit. The audit found:

20% of programmatic display spend was on low-viewability long-tail inventory (average viewability 35%)
Multiple reseller hops added a 12% combined markup that was not disclosed
IVT averaged 7% on certain exchanges

Actions taken: reclaimed contractual credits, renegotiated the SPO path to a direct SSP relationship, and inserted a makegood clause for future buys. Result: net media efficiency improved and the client recouped the equivalent of 18% of quarterly spend via credits and more efficient buys.

Advanced Tips for 2026 and Beyond

Leverage clean room reconciliation: Use a neutral clean room to reconcile conversions against placement-level cost without exposing PII. See our recommended analytics playbook for reconciliation patterns.
Require real-time telemetry where possible: For high-value campaigns, negotiate a real-time impression stream to detect issues faster and reduce waste.
Use automated audits: Build scripts to ingest the CSV template and run validation checks (missing domain, zero-cost rows, negative markups) automatically each week; orchestration and runbooks from cloud-native workflow orchestration make this scalable.
Push for short supply chains: Instruct agencies to prefer direct SSP relationships for high-value publishers to reduce hidden resellers.
Incorporate privacy impact reviews: With privacy regulations evolving, require agencies to document identity solutions used for targeting and how they handle consent and hashing.

Quick Decision Rules

Use these rules to decide next steps after an audit:

If placement transparency <70%: pause or reallocate spend until corrected.
If IVT >5% on premium buys: demand immediate remediation and credits.
If undisclosed reseller markups discovered: renegotiate contract and require full rebate of excess fees.

"Transparency is not an add-on—it's a procurement requirement. If an agency resists line-item visibility in 2026, they’re asking you to accept inefficient media economics."

Final Checklist: What to Keep in the Folder

When you finish an audit, have these documents centralized:

Placement-level CSVs for reviewed period
Third-party verification PDFs
Supply path maps and seller.json snapshots
Signed contract clauses on audit rights and makegoods
Remediation plan and SLA timelines

Conclusion & Next Steps

By applying this 10-point checklist you’ll move from trusting agency summaries to owning placement-level control. In 2026 the difference between optimized and inefficient media stacks is often simply visibility—and the willingness to insist on it. Run this audit quarterly, embed the contract clauses above, and animate remediation via your procurement and legal teams.

Call to Action

Ready to run your first principal media audit? Download our editable CSV template and contract clause pack, or schedule a 30-minute audit consultation with our team to get a prioritized remediation plan tailored to your accounts. Don’t let hidden placements erode your ROAS—take control today.

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