Compensation Estimate Methodology
Important: These are illustrative estimates only
Compensation figures shown on GuineaPig are algorithmic estimates based on publicly available research. They are not provided by study sponsors and are not verified. Actual compensation may be significantly higher, lower, or non-existent. You must contact the study team directly to confirm any compensation before enrolling in a clinical trial.
Why We Show Estimates
Most clinical trial sponsors do not publish specific compensation amounts on ClinicalTrials.gov. However, compensation is a key factor in participants' decision-making. To help users compare opportunities, we generate rough estimates based on publicly available research about typical clinical trial compensation practices.
These estimates are meant to provide a general sense of potential compensation ranges — not to make promises about what any specific study will pay.
How Estimates Are Calculated
Our algorithm considers the following factors when generating compensation estimates:
1. Study Phase
Phase 1 studies typically involve more intensive monitoring, frequent blood draws, and potential overnight stays. Published research indicates Phase 1 studies generally offer higher per-visit compensation than later-phase trials. Our estimates reflect these phase-based differences.
- Phase 1: Typically higher compensation due to greater time burden and risk
- Phase 2: Moderate compensation, often fewer visits than Phase 1
- Phase 3: Often lower per-visit rates but may involve more visits
- Phase 4: Post-marketing studies, variable compensation
2. Estimated Duration
We estimate study duration based on the start date and primary completion date listed on ClinicalTrials.gov. Longer studies typically involve more visits and therefore higher total compensation, though per-visit rates may vary.
3. Sponsor Type
Industry-sponsored studies (pharmaceutical and biotech companies) tend to offer higher compensation than academic or government-funded studies. Our algorithm applies different baseline rates based on sponsor classification.
4. Enrollment Size
Studies with larger enrollment targets may indicate more standardized compensation practices, while smaller studies may have more variable arrangements.
Data Sources and Research
Our compensation model is informed by published research on clinical trial participant compensation, including:
- Grady, C. et al. (2005) — "An analysis of U.S. practices of paying research participants." Contemporary Clinical Trials, 26(3), 365-375. This study analyzed compensation practices across 467 clinical trials.
- Dickert, N. & Grady, C. (1999) — "What's the price of a research subject? Approaches to payment for research participation." New England Journal of Medicine, 341(3), 198-203.
- CISCRP (Center for Information and Study on Clinical Research Participation) — Annual participant surveys providing data on reported compensation across study types.
- Industry benchmarking reports — Published compensation surveys from clinical research organizations, though specific figures vary significantly by region and study type.
Significant Limitations
Our estimates have important limitations that users must understand:
- No sponsor verification: We do not receive compensation data from study sponsors. Our figures are algorithmic estimates, not confirmed amounts.
- Geographic variation: Compensation varies significantly by location. Studies in major metropolitan areas often pay more than those in rural areas.
- Study-specific factors: Many factors affect compensation that we cannot account for, including specific procedures required, overnight stays, washout periods, and participant burden.
- Non-monetary compensation: Some studies offer non-monetary compensation such as free health screenings, travel reimbursement, or meals, which are not reflected in our estimates.
- No compensation at all: Some studies on ClinicalTrials.gov do not offer any compensation. Our algorithm may still show an estimate for these studies.
- Outdated research: Compensation practices change over time. Our model is based on historical research and may not reflect current market rates.
How to Verify Actual Compensation
Before enrolling in any clinical trial, you should:
- Contact the study team directly using the contact information on ClinicalTrials.gov. Ask specifically about compensation amounts, payment schedule, and any conditions.
- Review the informed consent document during the screening process. Compensation terms must be disclosed in the consent form.
- Ask about payment timing — some studies pay after each visit, others pay upon completion, and some pro-rate if you withdraw early.
- Clarify what's included — ask whether travel, parking, meals, and childcare are covered or reimbursed separately.
Our Commitment
We are committed to transparency about the limitations of our estimates. We do not:
- Guarantee any compensation amount
- Receive payments from study sponsors
- Have financial relationships with clinical research sites
- Enroll participants or handle any compensation payments
GuineaPig is a free search tool designed to help you discover clinical trial opportunities. The decision to participate — and verification of all study details including compensation — is entirely your responsibility.
Questions or Corrections
If you believe a compensation estimate is significantly inaccurate, or if you have information about a specific study's actual compensation, please contact us at hello@imaguineapig.com. We welcome feedback to improve our methodology.