Most established academic disciplines have their own journals and other outlets for publication, although many academic journals are somewhat interdisciplinary, and publish work from several distinct fields or subfields. There is also a tendency for existing journals to divide into specialized sections as the field itself becomes more specialized. Along with the variation in review and publication procedures, the kinds of publications that are accepted as contributions to knowledge or research differ greatly among fields and subfields. In the sciences, the desire for statistically significant results leads to publication bias.