Fig. 1

Example of medical influence diagram. A patient may suffer from a disease (X). Before deciding how to treat the patient (D), the physician can decide to perform a test (T). This test will produce the test result (Y), which would help to determine whether the patient suffers from the disease. The doctor has to select a strategy taking into consideration the morbidities associated to the test (U₁) and the health state of the patient after treating him (U₂)