Table 3 Smallpox, Boston 1721. Decision: inoculate or not (contd).

Path names	Path probabilities times outcomes
Do nothing, infected, live	(0.553)(0.854)(1)  = 0.472
Do nothing, infected, death	(0.553)(0.146)(0)  = 0. 0
Do nothing, not infected	(1−0.553)(1)  = 0.447
Expected value of do nothing	0.919