The phrase "an official study" is correct and usable in written English.
It can be used when referring to a research project or investigation that has been formally conducted or sanctioned by an organization or authority.
Example: "The findings of an official study conducted by the government revealed significant trends in public health."
Alternatives: "a formal study" or "a sanctioned study."
According to an official study of the program, New Yorkers didn't learn to buckle up.
The report sets out the findings of an official study that explores how the aforementioned technology "can revolutionise services, both in government and the private sector".
The National Farmers Union Scotland said it too was sceptical about Hillman's research and about the overall benefits, but said it would support an official study into the impact of the change.
In the view of Port Authority officials, those transmissions show beyond any doubt that the repeater worked, contrary to the accounts given in an official study of the emergency response that has been endorsed by Mayor Michael R. Bloomberg and Fire Commissioner Nicholas Scoppetta.
Behind all the football-induced euphoria, France remains a country where, according to an official study published earlier this month, four out of ten people admit to being bluntly "racist" or "fairly racist"—almost twice as many as in Germany, Britain or Italy.
Or, a few decades ago, if enough people gathered at a beach house on, say, Fire Island to qualify as an official study group, someone had to make a daily trip to the local post office to pick up that day's audio tape sent from Barbri.
Schools emerged based on the teachings of the Chinese philosophers Chu Hsi and Wang Yang-ming, and Neo-Confucianism became an official subject of study for warriors.
Charles Shrader, a retired Army lieutenant colonel who wrote an exhaustive official study of fratricide from World War I through Vietnam, likens the 1945 case to the current case.
And he should approve the Keystone XL pipeline, which would carry oil from Canada's tar sands to American refineries; an exhaustive official study has deemed the project environmentally sound.America does not ban the export of natural gas, but it makes getting permits insanely slow.
A senior judge today predicted fundamental changes to the court system following a groundbreaking official study into the jury process.
Meanwhile, several nations are expected to champion the need for a financial transaction tax, a plan that one official study suggested could cut growth.
