Software Architect's Handbook

Coincidental cohesion

Coincidental cohesion occurs when elements in a module are grouped arbitrarily. There is no relationship among the different elements, making it the lowest (worst) type of cohesion. Sometimes, you will see this type of cohesion in a utilities or helpers class where a number of unrelated functions have been placed together.

Coincidental cohesion should be avoided and, if it is encountered in a module, the module should be refactored. Each part of the module should be moved to an existing or new module where it would make logical sense for it to exist.