Screen Failure Rate Calculator
Calculation Results
Screen Failure Rate
Randomized Subjects
Screen-to-Randomization Ratio: 0:0
Success Percentage: 0%
Understanding Screen Failure Rates in Clinical Research
In clinical trials, the Screen Failure Rate is a critical performance metric that measures the proportion of potential participants who sign the Informed Consent Form (ICF) but do not ultimately qualify for the study based on inclusion and exclusion criteria.
The Screen Failure Formula
Calculating the screen failure rate is straightforward but essential for trial budgeting and timelines. The standard formula used by Clinical Research Associates (CRAs) and Study Coordinators is:
Why Monitoring This Rate Matters
High screen failure rates can significantly impact a clinical trial in several ways:
- Budget Overruns: Every screening procedure (labs, ECGs, MRIs) costs money. If 70% of screened subjects fail, the cost per randomized subject increases drastically.
- Timeline Delays: If the failure rate is higher than anticipated, the recruitment period must be extended to reach the target sample size.
- Site Burden: High failure rates can lead to investigator fatigue and administrative strain at the clinical site.
- Protocol Issues: Consistently high rates across multiple sites may indicate that the inclusion/exclusion criteria are too restrictive or unrealistic for the target population.
Example Calculation
Imagine a Phase II cardiology study where a site has screened 200 potential participants. Upon completing the screening procedures, 80 participants were found to be ineligible due to high blood pressure readings or conflicting medications.
- Total Screened: 200
- Total Failures: 80
- Calculation: (80 / 200) × 100 = 40% Screen Failure Rate
- Screen-to-Randomization Ratio: 2.5:1 (meaning for every 2.5 people screened, 1 is randomized).
Strategies to Reduce Screen Failures
To optimize the recruitment funnel, study teams often implement "Pre-screening" logs. Pre-screening involves checking basic criteria (like age or known medical history) before the formal screening process begins, ensuring that only highly likely candidates move forward to sign the ICF and undergo expensive testing.