Table 1 Interventions, Parameters, and Terms

Interventions

No Intervention

No Change

Status Quo

Change the Initial Conditions:

Let π' be π + λ(1 - π)

Move 100*λ% of the sick persons to healthy, at baseline only.

One-Shot

Improve the Probabilities:

P(S|H) * (1-α)

At every age, lower the probability of a healthy person getting sick by a factor of (1-α), perhaps through such health promotion and disease prevention activities as smoking prevention programs or vaccinations

HP/DP

P(D|H) * (1-α)

At every age, lower the probability that a healthy person dies, perhaps by improving automobile, workplace, or gun safety.

Safety

P(D|S) * (1-α)

At every age, lower the probability that a sick person dies, perhaps by improving intensive care units.

ICU

P(H|S) * (1+α)

At every age, increase the probability that a sick person becomes healthy, possibly by improving treatment.

Treatment

Parameters

λ

Proportion of sick persons moved instantaneously to the healthy state by the One-Shot intervention (usually set to 1.0)

α

Amount of improvement to a transition probability (usually set to 0.1)

β

Worth to society of an additional YSL divided by worth of an addition YHL (usually set to 0.5)

Relative Worth

π

Proportion who are healthy at baseline (usually set to 0.98 for birth cohort and 0.80 for retiree cohort)

Outcomes

YHL

Years of healthy life (years in excellent, very good, or good health)

YHL

YSL

Years of sick life (years in fair or poor health)

YSL

YHL + β*YSL

Worth-adjusted years of life

Worth