How it works

Your rules, checked on real, examined Americans. In minutes.

From protocol to number

Four steps. Nothing to install.

Give us your trial

Upload the protocol (PDF, Word, ODT, RTF, TXT, Markdown or HTML), paste the criteria, or enter a ClinicalTrials.gov ID.

Files are read in your browser; only the text is sent. You see exactly what we received before anything else happens.

A protocol, pasted criteria or an NCT ID.

Each criterion becomes a rule

Criteria become rules over survey measurements: age, BMI, blood pressure, HbA1c, kidney function, diagnoses, medicines.

Five validated trials use hand-written rules; for others an AI translates, using only a fixed list of survey questions. You can mark any rule as wrong; it is left out.

Shown next to the sentence it came from.

We count real people

The rules run on CDC NHANES. Each person stands for a known number of Americans, so the result is a national count with a range.

The AI never produces a number. Every figure comes from the engine.

Examined, lab-tested Americans.

You get the answer

Share and count of US adults with a range, the rules that exclude the most people, the one rule worth relaxing, what can't be checked, every assumption and a PDF.

The headline number is free. The full report is $349, one-time.

How many qualify, and which rule cuts most.

The data

CDC NHANES 2015–2018.

The only US survey where people are both interviewed and physically examined, with lab tests. It is the source used by the published studies we compare against.

11,268examined adults
243.8 millionUS adults they stand for

NHANES

People are interviewed at home, then examined in a mobile clinic: height, weight, blood pressure, blood and urine tests, medicines and diagnoses.

Measured: BMI, blood pressure, HbA1c, glucose, cholesterol, kidney and liver tests. Asked: diagnoses, smoking, pregnancy, PHQ-9. Medicines: prescriptions seen by the interviewer.

Run by the US CDC.

How we count

A person passes if they meet every inclusion rule and no exclusion rule. The share is the weighted sum of people who pass over the weighted total.

The range comes from the survey design (strata and clusters). Missing answers fail a "must have" rule and pass a "must not have" rule.

Weighted, with a 95% range.

The waterfall

Rules are applied one after another. We also drop each rule on its own and recount: the one that adds the most people back is your best candidate to relax.

People removed by each rule.

Where AI is used

AI maps criteria to a fixed list of 83 survey variables. It can't invent variables or run code, every rule is re-checked, and you review them before the count.

Only to translate wording.

How accurate it is

Within about 1 point on all five published trials.

All 7 published numbers (SELECT was published three times) fall inside our range. Largest gap: 0.9 points (SURMOUNT-1).

Wording matters most: a vague rule can move the result by about 4 points (STEP 1). The full protocol often removes several more points than the ClinicalTrials.gov summary (STEP 1: 37.4% → 32.0%).

Sources

Wong et al. 2023 (STEP 1) and 2024 (SURMOUNT-1); Bress et al. 2016 (SPRINT); Wong et al. 2020 (EMPA-REG OUTCOME); Lu et al. 2024 and Yan/Wong et al. 2025 (SELECT). All used NHANES.

STEP 1

semaglutide, obesity

Published
93.0M
Trial Fit
91.2M

−0.7 pts

SURMOUNT-1

tirzepatide, obesity

Published
93.4M
Trial Fit
91.3M

−0.9 pts

SPRINT

intensive blood pressure

Published
16.8M
Trial Fit
16.4M

−0.2 pts

EMPA-REG

empagliflozin, diabetes + heart

Published
1.86M
Trial Fit
1.75M

−0.4 pts

SELECT

semaglutide, heart disease

Published
3.7–6.2M
Trial Fit
3.9–6.3M

+0.0 to +0.2 pts

What we can't check

Listed openly, never mixed into the main number.

Where published US prevalence exists (for example a recent heart attack or stroke, about 0.1–1% of adults), the full report shows a rough range with its source, kept separate from the main number.

The data describe the US population, not who lives near your sites. Diagnoses are self-reported. Automatic rule translation can be wrong; you review every rule.

Recent events

"Heart attack in the last 60 days": the survey records if, not when.

Rare conditions

For example MEN2: too rare for a survey sample.

Tests not run

Calcitonin, imaging, ECG findings.

Administrative rules

Consent, willingness, investigator judgement.

Before you ask sites

Tune the criteria first. Ask sites once.

Manual feasibility asks specific sites how many patients they can recruit. Trial Fit answers what share of US adults meet your criteria, and which rule cuts the most people.

Trial Fit

Time
Minutes
Cost
Free preview, $349 report
Based on
Examined people, CDC NHANES

Manual feasibility

Time
Weeks
Cost
Thousands to tens of thousands
Based on
Estimates from sites

Ready for your own trial?

Upload your protocol or enter an NCT ID.

Create your report