Forensic Likelihood-Ratio Evidence Evaluation

Imagine two doctors examining the same X-ray: one argues the patient has a certain condition, the other disagrees. The likelihood ratio answers: 'How many times more likely is this X-ray if Doctor A is correct, compared with if Doctor B is correct?' A ratio of 100 means the X-ray is 100 times more consistent with Doctor A's position. The court then combines that ratio with its own sense of prior probability to reach a verdict — the scientist supplies the ratio, the judge weighs the priors.