a song of ice and fire - How much creative independence are the Show runners accorded in Game of Thrones?

Since Season 3, we have been observing that the show was taking a different direction than the books. Many important characters never made it into the show, others who are still alive were killed off.

As we know the show is supposed to be based on the books, not to be direct adaption of the books from print to television media, there's bound to be a certain degree of creative independence accorded to them by the author of the series, George R.R. Martin.

The question is, how much independence do they have? Do they still have to take GRRM on board with whatever changes they might intend to make? By "they" I mean D&D and the whole writers crew for the show. Given the number of significant changes they have made, I reckon the answer would be a lot. Has GRRM or HBO ever commented on that?

Answer

George answered this question in a recent interview with Meduza on 22nd August 2017.

Q: How independent are the showrunners from you? Simply put: could they save the life of a character you’ve decided to kill? Or could they kill someone who’s still alive in your books?

GRRM: They are independent. They can do whatever they want. I don’t have any power… any contractual right to [stop them]. I consult with them. I talk to them on a regular basis. Of course, years ago, we had a series of very long meetings, where I told them some of the big twists and turns and huge events that were coming in the last few books. So they’ve been touching [on] some of these, and doing some of the reveals, but they have also been departing in various ways.

The biggest one is one that you just mentioned: probably right now, right as we talk, there are close to 20 characters who are dead on the show, who are still alive in the books. Some of them are very minor characters, but also there are major characters, like Rickon Stark, Barristan Selmy, Myrcella Baratheon. All of them — dead on the show, but alive in the books.

There are also a number of characters in the books — fairly important characters — who have never been in the show at all. Characters who were omitted totally. It’s not a question of killing them; they’re just not there. They were never a part of it: Lady Stoneheart is one of them; Arianne Martell, the heir to Dorne, who’s a viewpoint character; and Victarion Greyjoy, one of the sons of Quellon Greyjoy and brother to Balon and Euron. All of these characters are quite important in the books and missing totally in the show.

And regarding his involvement in the show as compared to D&D's, he said the following in a separate interview to Time:

Q: How has your involvement in the show changed over time?

GRRM: I’m a co-executive producer on the show; David and Dan are the showrunners. Right from the first, we knew that they were going to do the lion’s share of the work, but I did wanted to be involved. Initially, I was involved in all the casting — I wasn’t physically present — I was here in Santa Fe. But through the wonders of the internet, I was able to look at all of the actors reading and to write them long letters and to have phone calls where I discussed which actors I like and which actors I didn’t like. And in the early seasons, I wrote one script per season. I would have gladly done more, but there just wasn’t time. I’m still trying to do these books. It takes me about a month to write a script and I didn’t have a month to spare, so I said, I think I’ll sit out season 5. I’ve sat out seasons 6 and 7 too, just trying to concentrate on this book, which as you know is massively late. So in that sense, my involvement in the show has diminished over time, though, I’m still here whenever they want to talk to me, and I’m always glad to weigh in. David and Dan have come to Santa Fe and we’ve discussed many of the ultimate developments, those landmarks that I spoke to at the end of the road that we’re both driving for. So I don’t need to be quite as involved as I was at the beginning.