
Bayesian belief network (BBN)
Separate what you observed from what could change under a decision, so a treatment, policy, or operational choice is not mistaken for a correlation.
A network of uncertain variables that updates their probabilities when you learn something new. This example separates a treatment's apparent association with recovery from its effect under stated causal assumptions.
Does recovery differ because of treatment, or because the treated patients started out sicker?
The circles are variables; their slices show probabilities of the possible states. Arrows encode this example's assumptions: severity matters for both treatment assignment and recovery. Treatment is fixed to treated in the pictured scenario.
Synthetic example, not real patient, customer or operational data.
Variables and symbols
- Severity
- How ill the patient is before treatment: mild or severe.
- Treatment
- Whether the patient is in the control or treated group.
- Recovery
- Whether recovery occurs: no or yes.

























