Includes index.

Part 1: Context. The importance of denominators ; When do diagnostic tests save lives? ; Beware of what seems too good to be true ; Why medical testing is never a simple decision ; Hierarchies and causes ; Assume a spherical cow ; Why some blockbuster drugs don't work for everyone ; When the brain gets in the way, part 1 ; When the brain gets in the way, part 2 ; The beautiful uncertainty of science ; In praise of not knowing ; A constructive way to deal with uncertainty -- Part 2: Evaluation. The study question ; Study design -- general scheme ; Observational studies ; Interventional studies ; Threats to validity : bias, misclassification, and generalizability ; Statistical analyses : measures of central tendency ; Hypothesis testing and measures of association ; Statistical significance, Type I and Type II errors ; Threats to validity : confounding and interaction ; Study results and conclusions -- Coda: Only the beginning.