The ex-Cub factor has nothing to do with the play of ex-Cub. This phrase was invented by Ron Berler. The ex-Cub factor states that any team with three or more ex-Cubs will not win the world series. Many think it is an after effect of the Billy Goat curse, being that curse which prevents the Cubs from reaching the world series.

Any team that an Ex-Cub plays on usually does better than his time with the Cubs. Thus, the Ex-Cub factor.