"of dubious validity" is correct and usable in written English.
You can use it when someone is questioning the legitimacy or accuracy of something. For example: "The witness's testimony seemed to be of dubious validity."
Having failed to build political coalitions, he relied on executive orders of dubious validity.
The suggestion that prostaglandins serve as endogenous ligands for nuclear receptors is presently configured on the use of synthetic compounds and immunoreactive quantitation of dubious validity.
Others are replete with exaggerated promises, fear-mongering warnings about voting for the other lot, and pie and bar charts of dubious validity.
Justice Scalia filed a statement explaining and agreeing with the majority's view that the proposal was of "dubious validity" given the Sixth Amendment's guarantee of the right to confront witnesses.
First, according to a lawsuit filed by the State of Vermont, it bought patents of dubious validity that could theoretically cover basic technologies, such as the scanning of documents.
The campaign comes at a time when government officials and some health specialists are expressing concern over the direct sales and advertising of genetic tests, some of them of dubious validity, to the public, mainly over the Internet.
The chairman of the panel said their practices ranged from "egregious to dubious validity".
In September, the committee accused the two firms of using places such as the Cayman Islands, so they do not have to pay US taxes, saying their methods ranged from "egregious to dubious validity".
Rather than a tempting fishing expedition into the murky waters of commercial data with known and hidden privacy perils as well as dubious validity, Pistole appears to be sticking to the solid ground of already privacy-validated programs.
But such an assurance is of dubious legal validity since only parliament or the courts are empowered to read down or change any statute.
Scientists excluded some nominal species of dubious taxonomic validity from this assessment.
