Script doctors are professional screenwriters hired by film, television, or theatre production companies to rewrite, polish, or enhance specific elements of an existing script. They are typically brought in during the development or pre-production phases to address issues like story structure, characterization, dialogues, themes, etc.
Generally, Indian filmmakers do not publicly acknowledge script doctors' efforts. This practice is not unique to India and is common in many film industries, including Hollywood. Production companies might not want to disclose that a script needed "fixing" by an outside writer, as it could be perceived as a flaw in the original script.
Since the makers of Anupama Parameswaran's Paradha have disclosed that their film has a script doctor, it must be considered extreme honesty. Will this become a trend in the coming years? Highly unlikely. Our filmmakers and producers don't give credit to all the screenwriters who work on their movies. So, expecting them to acknowledge the efforts of script doctors is a stretch.