The phrase "a misguided assumption" is correct and usable in written English.
It can be used when referring to a belief or idea that is based on incorrect information or reasoning.
Example: "The project's failure was largely due to a misguided assumption about the market demand."
Alternatives: "a false belief" or "an incorrect notion."
There is a misguided assumption that baby-sitting is sustenance enough for the aging, said Moina Shaiq, founder of the Muslim Support Network, which brings seniors together.
While there's been a lot of talk of kids second-screening, there's a misguided assumption that the television still reigns supreme.
That may be a misguided assumption, as a study published in the Leadership & Organization Development Journal has found that dropping a couple f-bombs on the job can actually go a long way.
All of us must take some responsibility that the loose and relaxed camaraderie that we share with our young performers has carried with it a misguided assumption that they are adults in an adult world, capable of making adult choices.
This is a seriously misguided assumption.
This, the ethos of the market economies since the Industrial Revolution, is grounded in a mythical and misguided assumption — that our resources are infinite.
During a recent interview with The Guardian, the "Grey's Anatomy" star broke down the "angry black man/woman" stereotype and the misguided assumption that a black person's anger is a product of being black.
Dish-hurling, name-calling parents were bad for kids, sure, but so were repressed parents who lingered in tepid marriages under the misguided assumption that a mother and father together were always better than either alone.
I also had made the mistake of taking on responsibility for my son's high school band jazz website (on the misguided assumption that, after a lifetime of avoiding any commitment to volunteering in any way at all, it was time for me to "give back" to the musical organization that had given so much to my son).
The only possible explanation for his determination to stick with Donald Rumsfeld, the defence secretary responsible for post-invasion planning and the disasters of Abu Ghraib and Guantánamo, is the misguided assumption that firing him would be a sign of weakness.
On the plazas outside, where scalpers still held to the misguided assumption they could get $500 CAN for tickets, a series of great roars came from within the stadium as American goals rocketed in the net: boom.
