It's hard to predict which songs will become hits. It's even more difficult to predict which artists topping today's charts will go on to record more hits and who will see their fame end.

To figure out if there's some kind of principle that can help explain who becomes a flash in the    an and who has a lasting music career, Justin Berg, a social scientist who researches creativity at Stanford University's business school, studied the songs from pop music charts. He used a database of about 3 million songs from 1959-2010 released by record labels that had produced at least one hit in the United States over that time. Of those songs, nearly 25,000 landed on the weekly Billboard Hot 100. That provided Berg with a list of nearly 4,900 artists who had one or more songs that made the list, his yardstick (标准) for defining a hit.

Hits are rare, the data show. Of the 69,000 artists in the original database, 93 percent never had a hit, 3 percent had one and 1 percent had two hits. The success rate for additional hits drops from there.

Artists with more variety in their music type have a better chance to land repeat hits. But there's a dilemma for artists who want to be popular over the long term. Variety isn't what helps artists land that first hit, Berg reports. It's the similarity of a new song to recent hits.

According to Berg's study, musical artists who produced music like other already existing music were about twice as likely to have their first hit. But those who created a more creative and varied music type before fame hit were more likely to make a series of hits.

However, Berg doesn't want his research to diminish (贬低) the accomplishments of one-hit wonders. "A lot of them in their time were quite famous and successful," he says. "You go out and try to make a song that catchy. It's not an easy challenge."