The phrase "a strong factor in" is correct and usable in written English.
It can be used to indicate that something plays a significant role or influence in a particular situation or outcome.
Example: "The economic downturn was a strong factor in the company's decision to downsize."
Alternatives: "a significant influence on" or "a major contributor to".
Income was a strong factor in the poll.
"We're already a strong factor in this next federal election," he said.
His expressed enthusiasm for undergraduate teaching was a strong factor in his selection.
1925 BUILDING PROSPECTS.; Public Works Will Be a Strong Factor in Year's Work.
That possibility was evidently a strong factor in Mr. Levy's decision to resign.
Archives|1925 BUILDING PROSPECTS.; Public Works Will Be a Strong Factor in Year's Work.
Yeoman's analogue-orphan status would, one suspects, be a stronger factor in his favour if all Academy members knew about it; as it is, many would probably be surprised to learn that Ida, with its rich, stark black-and-white imagery and old-school Academy-ratio framing, is a digital effort.
Because single parenthood is also concentrated among poor and racial minority groups, it's hard to tell whether being a single parent, being poor or being part of a certain minority group is a stronger factor in poor sleep and poor health.
Our findings suggest that such doubts are a stronger factor in GPs' VH than is their perception of side effects.
This social prestige might be a stronger factor in rural settings, because of the existence of more stable communities with stronger social fabric (compared to more unstable urban slum communities; Alam et al. 2012a).
We may infer that the limited free time among parents of young children is a stronger factor in influencing retention than the technological divide that one might expect to be an impediment for older adults.
