'a moderating effect' is correct and usable in written English.
It can be used to describe a situation where something is toning down, or limiting, the effects of something else. For example, "The presence of experienced industry experts had a moderating effect on the conversation, ensuring that it stayed on topic."
Political inclusion, it turned out, had a moderating effect on Islamists.
This has encouraged a sensibility that, until lately anyway, had a moderating effect on both religion and society.
These habits had a moderating effect even on that most imperious and authoritarian of Christian denominations, Catholicism.
"For the first 60 feet the steeple is hollow and open to the air, which creates a moderating effect," Mr. Bates said.
Many conservative Republicans -- and some members of his own administration -- do not accept the argument that trade has a moderating effect on China's political behavior.
Although the LibDems are supposed to be having a moderating effect, the bill still has many flaws – and the scars of battles with the Treasury are evident.
His critics portray him as slavishly bound to Mr. Bush and question whether he has had a moderating effect on Mr. Bush and the more hawkish members of the administration that his supporters have credited him with.
As China takes its place among the world's great powers, and attempts to integrate its economy into global markets, Beijing's need for foreign oil may have a moderating effect on Chinese behavior.
Any such large body of water has a moderating effect on the climate of its surroundings, said Anne Lenox Barlow, horticulture educator at the Cornell Cooperative Extension in Clinton County, N.Y.
Diaspora Tamils, who provided three of the four people sent by the Tigers to negotiate with the Sri Lankan government in 2002, have had a moderating effect on the movement, he reckons.
Among CSA survivors, childhood adversities exerted a moderating effect in terms of depressive symptoms.
