Build Tool 3
Bayesian Prior Calculator
Document an initial probability estimate before assessment, convert that prior to odds, apply a likelihood ratio, and record transparent assumptions for professional review.
Safety and ethics
This tool is intended for structured reasoning, training, and documentation. It does not determine truth, deception, guilt, liability, or credibility. Any prior probability must be interpreted alongside evidence, professional judgement, and the limits of the assessment method.
Legal and professional-use disclaimer
This tool is provided for qualified professional, research, educational, and documentation purposes only. It is not legal, clinical, investigative, or forensic advice and must not be used by unauthorised persons to decide facts, rights, obligations, employment, relationship status, admissibility, or case outcomes. Any unauthorised or non-professional use is at the user's own risk. Final decisions remain with appropriately qualified professionals.
2. Prior Probability Builder
The prior should be justified by transparent reasoning, base-rate information, case context, or clearly stated assumptions. Avoid using the calculator to decide facts.
Structured prior factors
3. Prior-to-Odds Conversion
Prior probability-
Prior odds in favour-
Prior odds against-
Initial support band-
4. Likelihood Ratio Input
Example labels below are illustrative placeholders only, not scientific claims about any specific test.
5. Posterior Calculator
Posterior values are conditional outputs from the selected assumptions. They are not factual findings.
LR used-
Posterior odds-
Posterior probability-
Change from prior: -
6. Scenario Comparison
| Scenario | LR | Posterior probability |
|---|
7. Sensitivity Analysis
Sensitivity posterior probability-