Young Adult book series are never a sure thing when being adapted to the big screen. However, it's become the most popular way movies are created due to the dedicated fan-base. There's also a downside to that since the creators have a lot of pressure with expectations from the fans of the books. The Hunger Games really understood this since the books had such a giant following and casting the characters became the most important part of making the film. Too much uproar from the fans would have led to bad press which meant that filming could have stopped before it ever got started.