If the values of two observations tend to rise and fall together over time, the observations are correlated. For example, the rise of violent crime in American society in the 1960’s and 1970’s matched the rise in violence on television. That lead to speculation that violence on television caused the increase. It is fair for correlation to raise such suspicions, but the correlation falls short of proof. Measures of violence on television continued to rise in recent decades, but crime rates have fallen. Young people commit more crimes, and the baby boomer population surge reaching maturity was the more likely cause of the the rise and fall.