"external factor" is a correct and usable phrase in written English.
For example: "The external factors affecting the economy have caused instability."
The external factor was subtler.
"All these geographic and time dependent changes really speak to the external factor," Hannun said.
That, he said, puts their happiness under the control of an external factor -- little better than luck and whim.
There is one external factor, possibly two, that Guardiola could not have foreseen.
But despite this external factor, Wenger deserves enormous praise for orchestrating such a rousing recovery.
"It's highly unusual for both of them to die like that, so it's got to be some external factor, or something internal".
But in its blog post, Dropbox said it "was incidental and not caused by any external factor or third party".
Over thousands of hours of such experiments, the lab's statistics show a small but verifiable effect of human intention on machines that is not attributable to chance or to any external factor.
Often, the dramatic tension in stories of the "married man meets forbidden woman" type comes from an external factor — the wife's suspicions, the man's fears for his eternal soul.
Modest controls may be legitimate in the first case, but not the second, he says.One external factor influencing capital movements may be American monetary policy.
Juhn, Rubinstein and Zuppann did find one external factor that appeared to have a big influence on these outcomes -- the cognitive abilities of the mothers.
