"not clearly stated" is a correct phrase that can be used in written English.
It can be used to indicate when something is not obvious or not understood. For example, "The purpose of the meeting was not clearly stated, so no one knew what to expect."
The chain of command is murky; the goals and the guiding philosophy are not clearly stated.
Documentation was poor and in 48.4% of orders for platelets, the indication for the platelet transfusion was not clearly stated.
4 Argument pertains to relationship between social factors and educational opportunity and is defensible, but it is not clearly stated.
Whereas the potentials of the methods have been well demonstrated, the assumptions and limitations behind them are often not clearly stated or not well understood.
In her book, Ms. Szymanski counsels parents that if it is not clearly stated how a certain list was compiled, "be suspicious".
The reason is not clearly stated in records, but some who knew him then believe it was because of the alarming threats he made at the training academy.
Administration officials have signaled that they are not open to a "containment" strategy toward Iran, but Mr. Obama himself had not clearly stated that view.
5.47pm: Blogger John Stone alleges that the senior author of the Nature study had a "competing interest" that was not clearly stated in the paper.
Hayek later added to his analysis, first by noting that knowledge, in addition to being localized, is often tacit (that is, implied but not clearly stated).
At a hearing at Punjab High Court here, the government said the Foreign Ministry had not clearly stated that the operative, Raymond A. Davis, was entitled to immunity.
Online accommodation community website Airbnb has "dozens of listings" in Israeli settlements on occupied Palestinian territory on the West Bank, which it has not clearly stated.
