"factors behind it" is a correct and usable phrase in written English.
It can be used to refer to the background or underlying causes or reasons for something. For example, "Experts are still trying to identify the factors behind it, but the cause of the drought remains a mystery."
This current stretch of good times, however framed, clearly has many factors behind it.
Still, there seems particularly virulent hostility to the Rohingya, which I think has a number of factors behind it.
Pundits bitterly debate the meaning of the shift, while economists struggle to tease out the factors behind it.
The most recent blackout was in early February the Australian Energy Market Operator said there were many factors behind it, including higher demand than anticipated.
After the most recent blackout in early February the Australian Energy Market Operator said there were many factors behind it, including higher demand than anticipated.
Democrats say that Mr. Ryan's remarks mask the larger issues behind the loss, and represent an inability to grasp other factors behind it.
The apparent presence of gambling syndicates with roots in Mumbai and Karachi was mooted as the primary factor behind it becoming a no-go zone for the Indian cricket team after the scandals of 2000.
Chinese is still far less common in schools or universities than Spanish or French, but it is surging and has the "cool factor" behind it — so public and private schools alike are hastening to add Chinese to the curriculum.
While the majority does not explicitly refer to Congress's intent as a driving factor behind its decision, it appears to have brought the application of AIA in line with congressional intent.
ISIS is a horrible group doing horrible things, and there are many factors behind its rise.
While Yingluck's link to Thaksin was one of the main factors behind her rise, it also meant she inherited his powerful opponents in the Thai establishment.
