Tullock Contest, explained.
A Tullock contest models competition in which costly effort increases the probability of winning a prize, while effort costs are paid even by the loser.
Why it happens
More effort can improve your chance relative to rivals, but each extra unit also has a direct cost. When rivals respond, participants can expend substantial resources competing over a prize without increasing its size. The contest rule determines how sharply effort translates into advantage.
A probabilistic contest rewards relative effort while making every contestant bear their own cost.
Read the result
Compare winning probability with expected payoff after effort cost. A higher chance of winning is not automatically a better decision if buying that chance costs too much.
A worked example
Two teams compete for a prize
Two teams each spend ten units competing for a 30-unit prize, with equal chances of winning.
Each has an expected prize of fifteen units and an expected payoff of five after its ten-unit cost.
Raising effort may improve one team's chance, but the extra cost and the rival's response must be included.
OPTIONAL DEEPER DETAILGo deeper: inside the model
Inside this model
The prize is worth 100. Your win chance is your effort divided by the sum of both efforts. Your expected net payoff is 100×win chance−your effort; a seeded play samples one winner and subtracts your effort whether you win or lose.
Where this idea is useful
A practical use
Two teams spending resources on a single prize may dissipate much of its value in competition.
A common misconception
“Winning probability is the same as return on effort.”
Return depends on prize size, cost, and competing effort. Losers still bear their costs under this contest rule.
What this explanation leaves out
- The rival effort is fixed and known; real contests have uncertain strategies and varied effort effectiveness.
Does this describe every competition?
No. Some contests refund costs, reward multiple winners, or produce useful output from effort. This model isolates a costly competition for a specified prize.
Does extra competitive effort create value or mostly redistribute the chance of winning?
Associated thinkers
Further reading
Explore the original research or the teaching reference behind this experiment.