Statistics as a Tool in the Physician's Black Bag

The era of evidence-based practice began in the 1990s with the hope patient outcomes would be improved by eliminating clinical bias and clinically unsound practices. Clinical guidelines which had been previously written by panels of experts were slowly replaced by careful analysis of existing clinical studies and more rigorous designs of new clinical studies based on sound scientific and statistical principles. This still leaves the practitioner with the responsibility of understanding what the evidence is showing them. This article reviews the statistical thinking that underlies the evidence-based literature. We will review some evolutionary changes to statistical analysis being advocated by statisticians and discuss some nuances related to the use of statistics describing diagnosis and treatment in clinical settings.