Twitter-driven predictions for Simon Cowell's US X Factor show were wide of the mark this week. The predictions from General Sentiment suggested that fans had given contestants Stacy Francis and LeRoy Bell the fewest votes.

The inference, said Ad Age magazine, was that they were for the axe on Thursday night and that Leroy Bell would be sent home. Both were actually safe.

Bell was described as a "crooning old timer" and one idea to do a better job in future is that more weight should given to Tweets for older contestants- as their fans are less likely to be on Twitter.

General Sentiment CEO Gregory Artzt. commenting on the blip, said, "There are some limitations. This is not a traditional research study with a representative population."

The "X-Factor" predictions were based on simple tweet volume.

"If we wanted to do a better job of this we would layer in sentiment, which is of course key to our business," said Artzt.

"Maybe some of the reactions for LeRoy Bell, although he didn't get much volume, were very positive.

"The other thing you can do with this is to try to make it a little bit more representative is to understand that certain singers might appeal to younger or older audiences."

Both Francis and Bell belong to the "Over 30s" category.

"There might be an audience for the older contestants that's not as much online," said Artzt .

For guessing "X-Factor" eliminations, though, said AdAge, General Sentiment will probably stick with the simple analysis. "The predicted bottom four
contestants did include the eventual bottom two."