Decision School
Learn the principles behind better emergency medicine through short, evidence-based deep dives on Bayesian thinking, diagnostic reasoning, cognitive biases, and emergency decision making.
The foundation
Bayes’ theorem
Bayes’ theorem is a rule for calculating the probability of an event given new evidence, using the event’s initial probability and the probability of observing that evidence.
P(D | E)
Posterior probability
The updated probability that the patient has the disease after incorporating the new evidence.
Clinical question
“Given where I started and what I just learned, how likely is the diagnosis now?”
Clinical walkthrough
The same result does not mean the same thing for every patient
See how a negative D-dimer changes the picture depending on your initial suspicion. This teaching example uses an illustrative negative likelihood ratio of 0.1.
Start with the prior
Prior probability
10%
Pretest odds
≈ 0.11
Apply the evidence
Negative LR (illustrative)
0.1
Multiply the odds
0.11 × 0.1 = 0.011
Arrive at the posterior
Post-test odds
≈ 0.011
Post-test probability
≈ 1.1%
Illustrative values for teaching only. Test performance and appropriate use depend on the assay, population, and clinical context.
Curated beyond the bedside
Perspectives Worth Exploring
Ideas from podcasts, videos, and articles—often outside medicine—connected back to better clinical decisions.
From SOLVED with Mark Manson
Making Your Predictions Explicit
Annie Duke explains on SOLVED with Mark Manson why making predictions explicit creates a feedback loop that helps you improve your decision-making.
From TEDxDanubia
How to Make Good Decisions
Mikael Krogerus and Roman Tschäppeler explore how information, timing, and reflection shape decisions. This talk provides a useful outside perspective for clinicians who often must act before certainty arrives.
A practical curriculum
Learn in the order that fits your practice
Choose a topic
Start with the clinical reasoning skill you want to strengthen.
Learn the framework
Use short, evidence-based lessons to build a durable mental model.
Apply it clinically
Bring the principle back to bedside decisions, calculators, and patient conversations.
Put the principles into practice
Apply Decision School frameworks with Bayes Razor clinical calculators.