The phrase "overstate the effect" is correct and can be used in written English.
This phrase is used when something has been made to seem more significant or important than it really is. For example, you could say "The media tends to overstate the effect of economic downturns."
It's impossible to overstate the effect of this liberation.
It's hard to overstate the effect his stuttering has had on his life.
"You can't overstate the effect of spending $80 to fill up your car.
He knows it is bogus to overstate the effect of their backgrounds but hopes their sensibilities will complement the opera and be 'a happy marriage of interests'.
It is hard to overstate the effect it could have if religious scholars agreed broadly to stamp out inflammatory interpretations of jihad.
But Frederic Friedel, a computer chess pioneer and the founder of the news site ChessBase, argues that it's possible to overstate the effect the victory had.
That sounds like a model that would tend to overstate the effects of major events that favoured one candidate or the other.
"Economists generally overstate the effects of uncertainty on spending, but in this case it does seem to be significant," he added.
But they also push up the unemployment rate by discouraging workers from looking for jobs as assiduously as they might otherwise do.It is easy to overstate the effects of this.
Be particularly skeptical when such claims are being peddled by the people who earn a commission on every ad they run, who naturally have an incentive to overstate the effects of ads and thus their own contribution to the election's outcome.
I have spoken mostly about the possible effects on the success of far right parties in Europe, my main expertise, and have been cautious not to overstate the effects.
