True story: Ten years ago, I had a two-script deal at ABC Studios, the television-production arm of the the Walt Disney Company. A “script deal” is different from a “production deal” mostly in the way you get paid. A production deal pays weekly for the term of the deal. A script deal pays in chunks, as various phases of a script’s development and subsequent drafts are completed.
Studios prefer to sign writers to script deals, for the obvious reason that they don’t have to pay a writer until the writer actually writes something. Writers prefer to sign production deals because every writer wants to get paid for doing as close as possible to zero. So, clearly, it’s a complicated relationship between studio and writer.