A variety of public campaigns, including the “Just Say No” campaign of the 1980s and 1990s that encouraged teenagers to “Just Say No to Drugs”, are based on the premise that teenagers are very susceptible to peer influences. Despite this, very little is known about the effect of school...

While recent research finds strong evidence that birth order affects children's outcomes such as education and earnings, the evidence on the effects of birth order on IQ is decidedly mixed. This paper uses a large dataset on the population of Norway that allows us to precisely measure birth...