The phrase "able to ascertain whether" is correct and usable in written English.
It can be used when discussing the ability to determine or find out if a certain condition or fact is true or false.
Example: "The researchers were able to ascertain whether the new treatment was effective in reducing symptoms."
Alternatives: "capable of determining if" or "able to find out whether".
Only well-designed, randomized, controlled trials will be able to ascertain whether CAM has any role in the management of patients with acute or chronic liver diseases.
Like most Wilder anecdotes, this tale has been told many times, and we have gone beyond the point of being able to ascertain whether it might actually be true.
An officer with the Somali police's investigative department told me that it had no leads on Mr. Gabow's murder and had not been able to ascertain whether he was killed because of his journalism.
By examining the oscillations, to learn of these differences, physicists should be able to ascertain whether neutrinos resemble other sub-atomic species, such as quarks and charged leptons (a family which includes the electron), or are a category apart.
"You have got to be able to ascertain whether the paper is of the age it's supposed to be and whether the ink is of the age it's supposed to be," says Trevan.
And only then shall we be able to ascertain whether we'll encounter the same difficulties we have described in learning about evolution by natural selection (see Review of the Literature).
We recognize that the wheezing-related results should be interpreted with some caution because we were not able to ascertain and differentiate whether wheezing resulted from asthma, COPD, or other respiratory disorders.
Studies published in languages other than English were included if: (1) the article was written in a language we were able to read (German, French, and Spanish); or (2) we were able to ascertain, from the English abstract, whether the study met the inclusion criteria.
Whether his memory had been reduced by the years or was deliberately selective I was never able to ascertain, but given such incidents continued throughout the competition Locatelli's recollections still seemed on the money.
