Define EVPI (Expected Value of Perfect Information) and explain when it is useful in decision making.

• A. EVPI is the maximum amount a decision maker would pay for perfect information; useful to determine whether further research is worth it.
• B. EVPI is the expected value of a decision with imperfect information.
• C. EVPI is the minimum cost to implement a strategy.
• D. EVPI is the variance of profits under certainty.

Answer: (A)

EVPI tells you how valuable perfect information would be before you act. It asks: if you could know the true state of the world before choosing an option, how much would that knowledge be worth on average?

When you face uncertainty, you choose an action to maximize your expected payoff given what you don’t know. If you had perfect information about which state will occur, you would always pick the action that gives the highest payoff in that specific state. EVPI is the difference between the expected payoff with that perfect information and the best expected payoff you can get without it. In practical terms, you’re calculating the maximum amount you’d pay for information that reveals the true state ahead of time.

This concept is especially useful for deciding whether to invest in further research, market testing, or information gathering. If the EVPI is high, obtaining additional information could significantly improve decisions and be worth the cost. If the EVPI is low, the value of extra information is limited, and resources are better spent directly on acting now.