Expected Value
The probability-weighted average outcome - what a decision is worth on average across its possible results. The rational basis for choosing under uncertainty.
- Term
- Expected value (EV)
- Is
- Probability-weighted average of outcomes
- Formula
- Σ (outcome × its probability)
- Use
- Compare choices under uncertainty
Forms & parts of speech
Definition in plain terms
Expected value, or EV, is a way to evaluate a decision whose outcome is uncertain by calculating the probability-weighted average of all its possible results. You take each possible outcome, multiply its value by the probability it occurs, and sum those products.
The result is what the decision is "worth" on average if you could repeat it many times. A bet with a 10% chance of winning $1,000 and a 90% chance of winning nothing has an expected value of $100 (0.10 × $1,000).
Expected value is the foundational tool for rational decision-making under uncertainty, because it lets you compare options with different probabilities and payoffs on a common basis.
It doesn't tell you what will happen in any single instance, but it tells you which choice is best on average - the right basis for decisions you make repeatedly.
Why it matters to growth leaders
Expected-value thinking is invaluable for growth leaders, because growth is full of uncertain bets - experiments, campaigns, new channels, and product initiatives, each with a probability of success and a range of payoffs.
Evaluating these on expected value, rather than on gut feel or the fear of any single failure, leads to better decisions over a portfolio of bets.
It justifies running experiments where a modest cost buys a chance at a large upside, even though most will fail - because across many such bets, the expected value is positive.
It also guards against being seduced by a high potential payoff that's too unlikely, or being scared off a smart bet by a small chance of loss.
For a growth leader running many initiatives, thinking in expected value - probability times payoff, across the whole portfolio - is the discipline that turns uncertainty into rational, repeatable decision-making.
The experiment has a modest cost and a small probability of a large payoff - say a 15% chance of unlocking a significant new growth channel and an 85% chance of producing little. Judged on the fear of likely failure, it looks unappealing.
But the growth leader calculates the expected value: the large payoff weighted by its probability comfortably exceeds the experiment's small cost, so on average - across many such bets - running it is worth it.
The leader recognizes that growth is a portfolio of uncertain bets, most of which fail individually, and that evaluating each on expected value rather than on the dread of any single failure produces better results over the whole portfolio.
Expected-value thinking justifies running the cheap experiment with big upside, while also guarding against bets whose tempting payoffs are too unlikely to clear the bar.
Turning uncertainty into probability times payoff across many initiatives, the growth leader makes rational, repeatable decisions instead of being ruled by the outcome of any one.
Formula
Synonyms & antonyms
Synonyms
Antonyms
Origin & history
Expected value - the probability-weighted average of outcomes - is the foundational tool for rational decisions under uncertainty; by combining each outcome's payoff and likelihood, it guides choices across a portfolio of uncertain bets like experiments and campaigns.
Etymology: source.
Usage trends
Search interest for this term over the last five years:
Common questions
- What is expected value?
- The probability-weighted average of all possible outcomes of an uncertain decision — each outcome's value times its probability, summed — giving a rational basis for comparing choices whose results aren't certain.
- How is expected value calculated?
- Multiply each possible outcome's value by the probability it occurs, then sum the products; a 10% chance of $1,000 plus a 90% chance of nothing has an expected value of $100.
- Why is expected value useful in growth?
- Growth is a portfolio of uncertain bets — experiments, channels, campaigns; evaluating each on expected value justifies running cheap bets with big upside even though most fail, since across many the expected value is positive.
Related tools & calculators
Resources & people to follow
- referenceWikipedia — expected value
- referenceDecision-science and growth practice
- referenceRGM analysis — growth is a portfolio of uncertain bets; judge each on probability × payoff, not the dread of a single failure
Curated, non-competitor resources verified per term.
Related training
Disciplines
Areas of marketing where expected value is a core concern: