Here is the typical cost comparison that sites discover when they run geotargeting against their previous broad-match approach: broad-area advertising produces clinical trial inquiries at $25–55 per inquiry with a 12–18% inquiry-to-screened rate, yielding cost-per-screened-patient of $140–450. Precision geotargeted campaigns produce inquiries at $30–65 per inquiry with a 28–42% inquiry-to-screened rate, yielding cost-per-screened-patient of $75–230. The inquiry costs more per click — but the screened patient costs half as much. This is why cost-per-inquiry is the wrong optimization target for clinical trial advertising.
Why Geotargeted Campaigns Produce More Expensive Clicks
When you narrow your geographic targeting, you are bidding on a smaller audience. Google’s auction system charges higher CPCs for more competitive, narrower audiences because more advertisers are competing for fewer people. A broad-area campaign might generate clicks at $2.10 average CPC. A precision-geotargeted campaign for the same keywords in a smaller zone might cost $2.80–3.40 per click. This higher CPC is not a problem — it is a feature. You are concentrating spend on the subset of the audience that converts.
The Full Funnel Cost Comparison
Running a full-funnel comparison requires tracking all four stages:
| Stage | Broad Match | Geotargeted |
|---|---|---|
| Cost per click | $2.10 | $3.20 |
| Click-to-inquiry rate | 4.5% | 6.2% |
| Cost per inquiry | $47 | $52 |
| Inquiry-to-screen rate | 15% | 35% |
| Cost per screened patient | $313 | $149 |
| Screen-to-enroll rate | 30% | 38% |
| Cost per enrolled patient | $1,043 | $392 |
In this representative comparison, geotargeted campaigns produce enrolled patients at 62% lower cost despite higher click costs, because every downstream conversion rate improves when the geographic quality of the audience improves.
How to Run Your Own 60-Day Comparison
- Duplicate your current best-performing campaign.
- In the duplicate: tighten geographic targeting to your top-quartile ZIP codes (based on historical enrolled patient origin data). Add demographic layers matching your protocol eligibility. Set Zone 1 bid modifier to +25%.
- Label the original “Broad Control” and the duplicate “Geotargeted Test.”
- Run both simultaneously with equal daily budgets for 60 days.
- At day 60: compare cost-per-inquiry, inquiry-to-screened rate, and cost-per-screened-patient between the two campaigns. The geotargeted campaign should outperform on downstream metrics even if cost-per-inquiry is slightly higher.
Presenting the Results to Sponsors
Sponsors increasingly ask for cost-per-enrolled-patient data as a recruitment quality metric. A geotargeted campaign that produces enrolled patients at $392 vs. a broad campaign at $1,043 is a compelling data point for the next sponsor check-in. It also demonstrates that your site is managing recruitment resources with analytical rigor — a differentiator that influences future study allocations.
48-Hour Action List
- Hour 1: Calculate your current cost-per-screened-patient and cost-per-enrolled-patient from the past 90 days using your ad spend and study management data. This is your baseline for the comparison test.
- Hour 2: Duplicate your top-performing Google Ads campaign. Apply ZIP code targeting (your top 10 enrolled patient ZIP codes), age demographic layer, and Zone 1 bid modifier (+25%). Label both campaigns clearly.
- Hour 3: Set equal daily budgets for both campaigns. Configure conversion tracking to fire on form submission so Google can report cost-per-conversion for each campaign separately.
- Day 2: Create a tracking spreadsheet with weekly rows for both campaigns: spend, clicks, inquiries, screened visits, enrolled patients. Update it weekly. At day 60, you will have the comparison data to make a permanent campaign decision and a sponsor-ready ROI analysis.