Author

Steven Levitt

24 key ideas across 3 books, each explained in our own words.

Freakonomics

IDEA 1
Incentives explain much of behaviour
Levitt and Dubner argue that incentives, whether money, social approval or moral feelings, are the key to understanding why people act as they do. Once you know what someone stands to gain or lose, surprising behaviour often starts to make sense.
IDEA 2
Even trusted people cheat
Using test data from Chicago schools, the authors show that some teachers changed students' answers when their pay or jobs depended on scores. They also find signs that sumo wrestlers sometimes fixed matches when one wrestler badly needed a win.
IDEA 3
Experts can exploit what they know
Estate agents know far more about the housing market than their clients. The authors find that agents tended to keep their own houses on the market longer and sell them for more, suggesting they did not always push hard for clients.

IDEA 1
Data can reveal surprising risks
Levitt and Dubner argue that per mile, walking drunk may be more dangerous than driving drunk. Their point is not to encourage drunk driving, but to show that careful data analysis can overturn common assumptions about risk.
IDEA 2
Altruism is more complicated
The authors examine experiments on generosity and the famous Kitty Genovese case, in which neighbours were said to have ignored a murder. They show that the original story was exaggerated and that human kindness depends heavily on circumstances.
IDEA 3
Simple fixes can solve big problems
The authors describe how cheap, simple solutions sometimes solve problems better than complex ones. Examples include the invention of seat belts and better hand-washing in hospitals to reduce infections. Clever thinking can beat costly technology.

IDEA 1
Admit what you don't know
Levitt and Dubner argue that people often pretend to know answers rather than admit ignorance. Saying I don't know is the first step towards learning, because it opens the door to gathering evidence and experimenting.
IDEA 2
Ask a better question
Many problems seem hard because we ask the wrong question. The authors suggest redefining problems in new ways, such as looking at causes instead of symptoms, to find more effective solutions.
IDEA 3
Think like a child
Children ask simple, obvious questions and are not afraid of seeming silly. The authors argue that this kind of curiosity helps adults notice things experts may overlook. Simple questions can expose hidden assumptions.

Go deeper with Steven LevittAsk questions, argue with the ideas and practise using them, free.