TL;DR: Most agency case studies show a best month, not typical results. A 2026 industry survey found 91% of marketers believe platform-reported numbers are overstated. Before you sign, verify PPC agency results with account access, full date ranges, and a reference call: a process that takes under an hour.
Why You Can’t Trust a Case Study on Its Face
Every agency pitch has a slide with a client logo, a big percentage, and an arrow pointing up. Almost none of them show you the account behind it. That gap is the whole problem when you’re trying to verify PPC agency results before signing a contract.
A 2026 survey of 210 senior marketing leaders by the Affinity Solutions Outcomes Marketing Council found that 91% believe platform-reported results are overstated to some degree. The same study found that 80% of marketers optimize campaigns using signals other than verified purchase data, and 35% of those in-flight decisions don’t hold up once reconciled against actual sales, according to Affinity Solutions.
Agencies buying media on your behalf face a similar transparency problem. The Association of National Advertisers’ December 2023 Programmatic Media Supply Chain Transparency Study analyzed log-level data from 21 major advertisers. It found that only 36 cents of every dollar entering a demand-side platform actually reaches the consumer. Non-transparent practices, including cash rebates to media agencies, were described as pervasive across the ad-buying ecosystem, according to the ANA.
The Federal Trade Commission tightened its rules around this exact behavior. Its revised Endorsement Guides, finalized on June 29, 2023, require that testimonials and case studies reflect what a typical customer can generally expect, not a best-case outlier dressed up as the norm, per the FTC. Most agency marketing pages ignore that standard entirely, and there’s little enforcement at the individual-agency level, so the burden falls on you.
Prospective client Google Ads accounts have come through our free audit process. A share of those accounts showed a gap between the pitch and reality once we looked at the numbers directly.
This matters more if you’re evaluating an agency for a high-ticket vertical. A law firm case study claiming a $45 cost per lead is meaningless without knowing whether those leads were personal injury or estate planning, since cost per lead in personal injury markets commonly runs five to ten times higher than estate planning. A SaaS case study claiming a 3x increase in trial signups is meaningless without knowing whether trial-to-paid conversion held steady or collapsed. Ask the agency to define every metric by your category, not a generic one.
None of this means every case study is fake. Most agencies aren’t lying outright. They’re presenting a best month, a best client, or a blended number that flatters the pitch. The fix isn’t skepticism for its own sake. It’s a repeatable process you run before any number changes your decision.
How Agencies Inflate Case Study Numbers, Even Without Lying
Four patterns show up over and over in agency pitch decks. None of them require fabricating data outright, which is exactly why they’re hard to catch without asking direct questions.
- Cherry-picked timeframes. A “312% increase in conversions” often compares one strong month against one weak month, not a full year against a full year. Retail around the holidays, law firms after a local news story, SaaS companies after a product launch: all of these produce spikes that have nothing to do with the agency’s work.
- Blended metrics that hide the mix. A blended return on ad spend number can look excellent while the non-branded, new-customer portion of the account underperforms badly. Branded search and remarketing convert at a much higher rate because the audience already knows the brand.
- Survivorship bias in the client roster. An agency with 60 clients and three great case studies isn’t showing you the other 57 accounts. Ask how many total clients they’ve managed in that vertical, and how the featured account compares to the average.
- Outdated case studies presented as current. A result from several years ago doesn’t reflect today’s auction costs or platform algorithms. Ask when the case study’s date range actually ended, not just when the deck was last updated.
The 7-Step Process to Verify Any PPC Agency Case Study
Run through these seven steps before any agency’s numbers factor into your decision. Budget 30 to 45 minutes total if you’re evaluating one finalist, or about two hours if you’re comparing three. Each step takes minutes, and a legitimate agency will not hesitate on any of them. If you’re mid-vetting, this pairs directly with our guide to the 23 questions that separate pros from pretenders, which covers what to ask beyond the case study itself.
1. Ask for read-only access to the actual account
A screenshot can be edited. A PDF can be cropped. Ask the agency to add you, or a neutral third party, as a read-only user on the actual Google Ads or Meta Ads account the case study references. For example, ask: “Can you add my analyst as a read-only user on the actual account for 48 hours so we can review the raw numbers?” A yes with a specific timeline is a good sign. A vague answer is not. If they say the client won’t allow it, ask for a call with that client instead. A flat no to both is a reason to walk.
2. Confirm the date range and check it against seasonality
A 40% jump in conversions means nothing if it happened between October and December for a retail client, or during a product launch month for a SaaS company. Ask for the exact start and end dates behind every number in the case study. Then compare that window against the client’s industry calendar. A landscaping company’s record quarter in spring is weather, not marketing.
3. Isolate branded search and remarketing from new customer growth
An agency can inflate a blended number by weighting the account toward branded search and remarketing spend, both of which convert far more easily than cold prospecting. Ask for the split between branded, non-branded, and remarketing spend and results. A share of the accounts we’ve reviewed showed this exact pattern. If the agency can’t produce that split for an account they claim to manage, the headline number is not trustworthy on its own.
4. Confirm the client name and industry actually match
Some agencies present a case study under a generic label, like “national law firm” or “regional SaaS company,” so they can reuse the same slide across different pitches. Ask for the real client name, or at minimum a verifiable way to confirm the industry, market, and account size match what’s described. A reputable agency can share specifics under an NDA if needed.
5. Cross-check the advertiser in Google’s Ads Transparency Center
Google’s Ads Transparency Center, launched March 29, 2023, is a public, searchable archive of ads served by verified advertisers across Search, YouTube, and Display, according to Google. Search the client’s brand name there. You can confirm whether the advertiser actually ran the campaign types, timeframe, and formats the case study describes. It won’t show you cost or conversion data, but it will catch a claim that doesn’t hold up against what actually ran.
6. Request a live reference call, not a written testimonial
A written quote can be drafted by the agency and approved with a rubber stamp. A 15-minute call with the actual client lets you ask follow-up questions: What was your budget before and after? Did you change your website, offer, or pricing at the same time as the campaign? Would you hire this agency again, today, at the price they’re quoting you? Hesitation to set up this call is itself a data point.
7. Compare the numbers against public industry benchmarks
If a case study claims a 12% conversion rate in a category where the realistic range is 2% to 4%, ask why. Benchmark reports from ad platforms and industry associations give you a sanity check before you take any single agency’s number at face value. An extraordinary claim needs an extraordinary explanation, not just a bigger logo on the slide.
Common Excuses, Translated
Every agency has a reason ready when you ask for verification. Some are legitimate. Some are stalling. Here’s how to tell the difference.
- “Our client agreements don’t allow account sharing.” Translation: this is negotiable in most contracts. Ask for a redacted screen share instead of a flat refusal.
- “That case study is a few years old, but the strategy still applies.” Translation: ask for a current example. Auction dynamics and platform algorithms change every year.
- “We can share results, but not client names, for confidentiality.” Translation: reasonable, but insist on a reference call under NDA instead of a written quote.
- “Our best clients don’t want to be featured publicly.” Translation: fine, then offer anonymized account access instead of just the headline number.
Red Flags vs. Legitimate Signals
Use this table as a quick reference while you’re on a discovery call with an agency.
| Red Flag | Legitimate Signal |
|---|---|
| Only screenshots or PDFs offered, no account access | Willing to grant read-only access or a live screen share |
| Anonymous client name, like “a leading retailer” | Named client, or a clear reason for anonymity plus a verifiable industry and size |
| Single best month cited, no full date range shown | Full campaign date range with before-and-after context |
| Blended ROAS or ROI with no channel breakdown | Breakdown by branded vs. non-branded, new vs. returning customer |
| No mention of budget, seasonality, or site or offer changes | Explains what else changed alongside the campaign |
| Refuses or delays a reference call for weeks | Offers a reference call within a few business days |
What a Legitimate Case Study Includes
- The exact date range the results cover.
- The starting baseline, not just the ending number.
- A channel and campaign type breakdown, including branded search separated from the rest.
- Context on what else changed: budget, website, offer, or pricing.
- A named client, or a verifiable path to confirm the industry and account size.
- A willingness to provide account access or a reference call on request.
If a case study is missing more than one of these, treat the number as marketing copy, not evidence. This is the same standard the FTC now expects advertisers to meet for public-facing testimonials, and it’s a reasonable one to hold your next agency to in a private pitch.
Verifying Case Studies Is One Part of a Bigger Vetting Process
Case study verification catches fabricated or cherry-picked results. It won’t catch a bad contract, a misaligned pricing model, or an agency that’s simply the wrong fit for your budget or industry. Pair this process with our guide to the 23 questions that separate pros from pretenders before any first call, so verification is one step in a larger checklist, not the only one.
Once a case study checks out, the next question is cost. Our breakdown of what agencies actually charge in 2026 shows what a fair rate looks like for your budget and industry, so a verified case study doesn’t lead you into an overpriced contract anyway. Run any quoted rate through our Agency Fee Comparison Calculator to see how it stacks up against the market before you sign anything.
If the case study you’re evaluating includes an audit claim, like “we found $40,000 in wasted spend,” compare it against what a real Google Ads audit should include. A thorough audit covers 47 distinct account elements. If the agency’s audit behind that number covered five, the wasted-spend figure is not reliable.
For the full vetting process from first call to signed contract, work through our PPC agency buyer’s checklist. It covers case study verification alongside contract terms, reporting cadence, and scope, in order.
Get a Second Opinion Before You Sign
The fastest way to know if a case study’s claims are realistic for your account is to see your own numbers evaluated by someone with no stake in the sale. iClick manages $61M+ in ad spend for clients ranging from law firms to SaaS companies to entertainment brands, and we’ve reviewed enough competitor case studies during onboarding audits to know which patterns hold up and which don’t.
Get a free written PPC audit of your current account. We’ll show you where your spend is actually going, benchmarked against real accounts, not a pitch deck. If you’d rather talk it through first, book a call and bring the case study you’re trying to verify. We’ll help you figure out what questions to ask before you sign anything.
Related on iClick
Sources
- Affinity Solutions: The Optimization Blueprint for Brand Growth (2026)
- ANA: Programmatic Media Supply Chain Transparency Study (December 2023)
- FTC: Federal Trade Commission Announces Updated Advertising Guides to Combat Deceptive Reviews and Endorsements (June 2023)
- Google: Announcing the Launch of the New Ads Transparency Center (March 2023)
Frequently asked questions
What’s the fastest way to verify a PPC agency’s case study?
Ask for read-only access to the actual account behind the numbers, even for 48 hours. A legitimate agency grants this or arranges a call with the named client within a few days. If they stall on both, treat the case study as unverified and move to the next finalist on your list.
Should I trust a case study without a named client?
Not on its own. Anonymous case studies are common for confidentiality, but the agency should still confirm the industry, account size, and market under an NDA. If they won’t verify any detail beyond the headline number, the result could belong to a very different type of account than yours.
How do I know if a PPC case study’s numbers are cherry-picked?
Ask for the exact date range and compare it against the client’s seasonal calendar. A single best month, a post-launch spike, or a holiday quarter can produce numbers that have nothing to do with the agency’s skill. Full year-over-year data is a stronger signal than any single month.
Does the Google Ads Transparency Center show campaign results?
No. It shows which ads a verified advertiser actually ran, on what platforms, and during what timeframe. It won’t show cost, clicks, or conversions. Use it to confirm a case study’s claims about what ran are accurate, then verify the actual results through account access or a reference call.
What should I ask a client reference about an agency’s case study?
Ask what their budget was before and after the engagement, whether they changed their website, offer, or pricing at the same time, and whether they’d hire the agency again at the current rate. These answers reveal whether the agency’s work drove the result or just happened alongside it.
