Birth Rate
A little town had a high birth rate that had attracted the attention of the sociologists at the local university.
They wrote a grant proposal, got a huge chunk of money and hired a few additional sociologists, an anthropologist, and a family planning and birth control specialist.
They moved to the town, rented offices, set up their computers and and began designing some questionnaires.
While the staff were busy getting ready for their big research effort, the project director decided to go to the local cafe for a cup of coffee.
He sat down at the counter, ordered his coffee, and while he was drinking it, he told the owner what his purpose was in town, then asked him if he had any idea why the birth rate was so high.
"Sure," said the owner. "Every morning the six o'clock train comes through here and blows for the crossing. It wakes everybody up, and, well, it's too late to go back to sleep, and it's too early to get up."