Statistics: "(s/week) - (q/week)"

"Meehl was an American psychologist who studied the successes and failures of predictions in many different settings. He found overwhelming evidence for a disturbing conclusion. Predictions based on simple statistical scoring were generally more accurate than predictions based on expert judgment.

A famous example confirming Meehl's conclusion is the 'Apgar score,' invented by the anesthesiologist Virginia Apgar in 1953 to guide the treatment of newborn babies. The Apgar score is a simple formula based on five vital signs that can be measured quickly: heart rate, breathing, reflexes, muscle tone, and color. It does better than the average doctor in deciding whether the baby needs immediate help. It is now used everywhere and saves the lives of thousands of babies. Another famous example of statistical prediction is the Dawes formula for the durability of marriage. The formula is 'frequency of love-making minus frequency of quarrels.' Robyn Dawes was a psychologist [...]. His formula does better than the average marriage counselor in predicting whether a marriage will last."

(http://www.nybooks.com/articles/archives/2011/dec/22/how-dispel-your-illusions/)

(I tracked down the original Dawes study: "Linear prediction of marital happiness" by J.W. Howard and R.M. Dawes in _Personality and Social Psychology Bulletin_, 1976, pp. 478-480. Now to track down the actual article... will have to go to the library I believe.)