Opinions differ as to whether a child’s discipline in one answer means the same will apply in the other two. One of Karlan’s partners this year, economist Jodi Beggs of Northeastern University, meticulously rations out her candy but throws her costume together at the last minute.

“You would really hurt this prediction,” Karlan told her in a conference call to get ready for the big night.

“You have to save the best candy for last!” Beggs replied. “You can’t waste it at the front.”