The phrase "the underlying factors" is correct and commonly used in written English.
You can use it when discussing the root causes or fundamental reasons behind a certain issue or situation. Example: "The success of the company was attributed to the hard work and dedication of its employees, but upon closer examination, it was revealed that the underlying factors were actually the strategic leadership of the CEO and the company's innovative marketing strategies."
That was one of the underlying factors in the buildup to the financial crash.
We know the underlying factors behind our success and we need to stay true to ourselves.
But the underlying factors that drove prices to their records in recent years have not really disappeared.
The article, however, fails to recognise some of the underlying factors in the rail network of today.
Only then can journalism begin to help us all understand the underlying factors in our elections and provide the context for societies to self-govern.
"I think the underlying factors regarding the riots are plain for anyone with eyes to see … It seems to me any economic structure that could give young people a future has been destroyed.
Later on in that same paragraph the reader is confronted with this: "The end product is a more robust and time-consistent combination of asset classes that map clearly to the underlying factors".
"Scientifically, we need to move on and identify the underlying factors that have caused the effects that we see," the lead author, Dr. Lars J. Vatten of the Norwegian University of Science and Technology, said in an e-mail message.
Her intervention comes after research by Lynton Crosby, who was David Cameron's chief strategist in last year's election, showed how important the underlying factors such as age and turnout will be to the outcome of the EU vote.
Atul Gawande's thoughtful piece on the Republicans' alternative to Obamacare doesn't mention one of the underlying factors, which he has written about before, that will affect any national plan from any party (Comment, March 6th).
Scholars are similarly eager to understand the underlying factors that promote household natural hazard preparedness.
