The phrase "a study that compared" is correct and usable in written English.
It can be used when referring to research that analyzes or evaluates differences or similarities between two or more subjects, groups, or variables.
Example: "The study that compared the effects of different diets on weight loss provided valuable insights into nutrition."
Alternatives: "a research that analyzed" or "an investigation that contrasted".
The finding came from a study that compared the two drugs in 20,000 high-risk women.
Bergstrom pointed the class to a study that compared the language used in letters of recommendation for male and female applicants for chemistry jobs.
In 2010, British researchers reported results of a study that compared 19 novice hikers who used trekking poles with a control group of 18 who did not.
Richard Rothstein writes that a study that compared Cleveland students who received vouchers with public school students who wanted vouchers but did not receive them showed "no significant differences in scores".
For example, a study that compared 56 patients given a soy drink with 55 who drank a medically inactive liquid found no difference between the groups, although both groups got some symptom relief.
In December the group released a study that compared birth records from California from 1983 to 1997 in Redlands, where perchlorate has been detected, with communities in San Bernardino and Riverside counties, where perchlorate has not been detected.
An artery works far better than a vein for replenishing the heart's blood supply in coronary bypass operations, according to a study that compared the long-term results of the two methods.
So researchers are reporting after a study that compared preschool-age children with chimps and capuchin monkeys when solving a puzzle.
Kellogg had indeed commissioned a study that compared children who ate Frosted Mini-Wheats for breakfast with children who had only water for breakfast.
The clash over effectiveness was crystallized in one edgy exchange between Straus and Dr. Anthony Nicholson, a British neuroscientist, one of the Schering-sponsored clinical researchers, over the interpretation of a study that compared loratadine to a sedating antihistamine called tripolidine.
In a study that compared the reasons why Japanese and American college graduates leave their jobs, American women cited child care and looking after elderly relations as the main factors.
