The phrase "a question of expertise" is correct and usable in written English.
It can be used when discussing a matter that requires specialized knowledge or skills to address or resolve.
Example: "When it comes to the technical aspects of the project, it's truly a question of expertise that only a few can handle."
Alternatives: "a matter of expertise" or "an issue of expertise".
It adds: "The fact that austerity is widely perceived by much of the public as sound economic policy should tell us that credibility on the economy is less a question of technical expertise, as it is of having a convincing story".
Being a dancer is a question of discipline and expertise, no matter the genre, and mutual respect is the order of the day.
"It is a question of growing that kind of expertise, it's not half an afternoon's workshop".
"It's more a question of drawing on the expertise of declared nuclear weapons states," he said, to expedite the analysis of the enormous declaration.
This last result contradicted the face-specific processing hypothesis and raised the question of expertise for this component.
Whether his birth-order also gave him access to a different kind of fictional voice is a question beyond my expertise.
In this study we address the question of whether expertise can be gained in a triple-conjunction (color, spatial frequency, and orientation) search task when both the features and spatial location of the target are changed from trial to trial while maintaining a persistent level of bottom up uncertainty in the Shanon entropy sense.
… We don't make you teach, we don't make you do committee work, but if one of your colleagues comes down the hall and says, 'I have a question in your area of expertise.
Surprised by a question outside his area of expertise —whatever that might be — he declares that in his view "war is unforeseeable".
There is some evidence that organic growers define for themselves a sphere of expertise like the conventional growers, and they do question consumers' knowledge over agricultural issues.
