Dara Resnick Creasey writes about her first time being the [staff writer on set](http://hollywoodjournal.com/industry-impressions/youre-all-set/20140423/):
> In the fall of 2007, my husband-and-writing-partner and I began production on the first episode of television we were ever asked to produce — an episode of Bryan Fuller’s Pushing Daisies called “Bitches” about a polygamist dog breeder (played by Joel McHale) who is killed by one of his four wives.
When the writer of an episode is on set, she has to balance the intention of the scene as scripted and the realities of production.
> How often you give the director notes depends on the showrunner (does he care about whether the words are said precisely as they’re written on the page?), the director (is she collaborative or combative?), the actors’ moods (have there been eight Fraturdays ((“Fraturday” is when production starts late enough on Friday that you’re really losing your Saturday.)) in a row?), and several other factors. Ultimately, the director will move on to her next gig, and you will have to answer to the showrunner, who will want to know why you did or did not get that shot you all discussed in the concept meeting (yes, that’s another real TV term) before production started.
> On the other hand, you also don’t want an entire set full of people grumbling because this is the 18th time today you stopped them from moving on because an actor didn’t say the words as you had them in your head.
In features, the screenwriter sometimes serves the same function, reminding the director why the scene is in the movie, and why it really does matter that this character says a specific line.
But there’s an important difference: the TV staff writer can say, “This is what Bryan wants.” If need be, she can evoke the authority of the showrunner. In features, the screenwriter rarely has that card to play, so he needs to find other means to get notes heard.