Thoughtful people oppose farm subsidies. Rapid growth of the money supply will cause inflation. The sales tax on food should be repealed. The increase in the cost of medical care must be slowed. After every fall election, the weather starts to turn cold.
Elections cause cold weather.
These statements confused positive and normative analysis. A student football team manager examined variables influencing the team's record and concluded that the best scores resulted when the third-string team played the most minutes. Therefore, he recommended that the third-stringers become the first team. This conclusion was probably erroneous because the manager has confused positive and normative analysis. Your opportunity cost of attending a football game is the subjective value of the hardship if your team loses.