This is my rough understanding of who gets what credit.

"Story by" credit - if a film is made from Michael's brilliant story idea, but Michael never wrote a single word for the script, he will get this credit.

"Screenplay by" credit - Ok..again Michael has a great idea about his thrilling story, but John is the one who puts it on the paper.  Eventhough Michael works so hard with John giving out ideas and scenes, John is the ONLY one who will get this credit.  It will be like "Story by Michael" and "Screenplay by John"

"Written by" credit -  This is what every writer's dream to see on a big screen.  If Michael writes the script using his own story idea, then he will get this credit.  In order to get this big one, you will need to own the story and also have to write.

Did I nail it?  Please correct me so if I did not ladies and gents.

One more question.
If the studio likes my script, but they will hire a professional writer to rewrite the whole thing, do I still get "Written by" credit, or would it be "Written by Michael & The Whoever the new writer who rewrites?

Oh..one more one more.
Is it really really really true that ALL scripts are rewritten.  All the scripts you are reading today are not the originals?  If I wrote a script about a kid from Virginia Beach goes to China and get bullied by Chinese kids, I will see a film about a kid from Virginia Beach going to China and compete for Olympics.  It will be totally changed.  If I was a writer, I will be outraged to see the big difference on the screen.

You are basically correct on the first 3 credits. You'll see "Story by" if the original idea came from someone who did not actively participate in the screenwriting process. This can happen if a producer/director has an idea/notes and hires a screenwriter to complete the draft. "Written By" is basically the same as "Screenplay by."

The only caveat is that it could possibly change according to the contract that is written up for the screenwriter. Maybe the "idea" person wants a screenwriting credit too; even though he/she does not participate.

A studio (let's say a Hollywood Prod Co.) may have a team of internal writers; but it does not necessarily mean they will automatically re-write scripts the company picks up. Again, it's all to do with the writer's contract and what the production company wants to do with the script/idea. Some contracts will offer the current screenwriter "first re-write option" on all further drafts. That means you would have first chance of doing the re-write, if you don't do it, the company has the option of hiring another writer. Your contract would also stipulate if you receive a writing credit regardless of the re-write process.

Many, many scripts are re-written; probably most. Doesn't mean it isn't re-written by the original writer for producer/director/actor notes though. Again, all in the contract. Some scripts will have multiple writers and multiple credits. Some scripts will have a "ghost writer" do a draft or too, but the original screenwriter keeps the sole credit. A few scripts are so in synch with the director/producer that it will go straight to shoot... and even then you'll have actor's re-wording scenes and dialogue.

Hope that helps.
Stew

As far as I've been told from various articles online, the original screenplay is never the same when it comes out on film. The general idea of the story will still be there, but minor things might be tweaked according to what the actor's and director's preferences. Film making is a collaborative effort. Suggestions about any changes made to a script are constant. Without these minor tweaks, the actor's aren't likely to feel comfortable with what they're doing and you probably wouldn't have a great performance. Be greatful with these tweaks. They are probably for the best.

As Stew said it is probably down to what is written in the contract. Have a close read at those little buggers.

I have no experience with this, by the way. I'm just basing my response on what makes sense.

Dan

Generally, shorts will be closer to original script than features.  According to most of the "professional" screenwriters I've spoken with or articles that I've read, you shouldn't expect more than 15 pages of what you've written to make it into the final movie.

This will vary with how independent the production company is and the budget of the film.  And, of course, you can expect the finished product to be much closer to the original script if you direct it.