Yes and no? Improve is off the top of your head and is usually an acting method or exercise.. writers do not improv. the writer may give prompts to have an actor or speaker go off the actors own ideas, but there is no structured writing and ideas coming from the writer going into the content of the improv exercise or method.. whose line is it anyways, is a good example.. there are prompts for the actors, but all content came from the actor themselves.