Prediction markets have exploded in popularity over the past few years, with platforms like Polymarket and Kalshi drawing millions of users. But not all prediction markets work the same way. Understanding the prediction market definition and the different types of contracts available helps you choose the right platform and make smarter trades. Whether you’re forecasting elections, economic indicators, or sports outcomes, knowing prediction market basics gives you a clear edge in how you interpret prices and crowd wisdom.
Binary yes/no markets and where they shine
Binary markets are the simplest and most popular type of prediction market. Traders buy shares that settle at either $1 or $0 based on whether an event happens. If you think the Federal Reserve will cut rates in July 2026, you buy “Yes” shares. If the cut happens, your shares pay $1 each. If not, they expire worthless.
This structure makes binary contracts easy to understand. The current price reflects the crowd’s probability estimate. A share trading at 68 cents means the market thinks there’s a 68% chance the event occurs. Platforms like Polymarket built their reputation on binary markets for elections, crypto prices, and world events. The wisdom of crowds shines here because thousands of traders aggregate information faster than any single expert.
Trading a binary contract on Polymarket
When you open Polymarket, you’ll see dozens of binary questions. Click any market and you’ll find a simple interface showing “Yes” and “No” prices. You pick a side, enter your amount, and confirm. The platform matches your order with other traders or liquidity pools. Your position updates in real time as new information moves the market. It’s that straightforward, and that’s why binary markets dominate prediction market mechanics today.
Scalar markets for numeric outcomes
Scalar markets let you bet on a range of numeric outcomes, not just yes or no. Think of forecasting the S&P 500 closing price on December 31, 2026, or total goals in the World Cup final. The contract settles at a value between a minimum and maximum, and your payout scales with how close the outcome lands to your prediction.
Kalshi offers scalar markets for economic data like unemployment rates and inflation figures. Traders who nail the exact number earn more than those who guess close. This format works well when precision matters and binary framing oversimplifies the question. Scalar markets require deeper analysis but reward accuracy with higher returns.
Categorical markets for multi-outcome events
Categorical markets handle questions with more than two possible answers. Who will win the next presidential primary? Which team will win the championship? Each outcome gets its own contract, and probabilities across all options must sum to 100%.