The phrase "a core reason" is correct and usable in written English.
It can be used to identify a fundamental or primary cause behind a situation or decision.
Example: "The lack of funding was a core reason for the project's failure."
Alternatives: "a fundamental reason" or "a primary reason".
"A core reason we started this company was to make it easier for people to get involved in philanthropy.
It found that more than two-fifths of finance firms gave access to European markets as a core reason for choosing London.
This presumption has fueled the belief that future 9/11's can be avoided only by a wholesale transformation of Muslim societies, which in turn was a core reason for broad public support of the invasion of Iraq.
But there's nothing to be done with the screenplay by Carey W. Hayes and Chad Hayes ("House of Wax"), which, at least in its onscreen manifestation, bags and sags without finding a core reason for being.
A core reason behind Qantas' under-performance is that the people directly affected by its operations passengers, employees, citizens are excluded from participating in the major decisions of the enterprise.
Wall Street critics blame the outsize salaries of bank employees as a core reason for the global financial crisis, arguing that the promise of large pay packages led to excessive risk taking.
"Never forget that none of these features should actually be a distraction from the core reason you're watching sport in the first place," says Henry. "Those who think it is will have a misunderstanding of the true value of these services, which is to enhance experience, not distract from it".
But that brings a mixed fate: "The core reason we're all leaving Woot is because we've lost the ability to do what's best for our brand and culture.
That means content comes infrequently and is stale – just the opposite of the core reason for using an RSS reader.
There was a core business reason for this purchase around cloud revenue.
This is the core reason, EM binary images have a lot of noise factor (Fig. 4).
