It was not possible, however, to obtain such data in this retrospective study.
Since it was a retrospective study, probably even more than that number had taken aspirin.
It also suffered a weakness common to all such retrospective studies.
In such retrospective studies, he said, people may not accurately remember what they really weighed.
Initial retrospective studies reported an average survival from diagnosis of only about 12 months.
With retrospective studies, the temporal relationship is frequently difficult to assess.
However, such retrospective studies were subject to certain biases that may have affected the results.
Bird collections are becoming increasingly important for use in retrospective studies.
I have made a retrospective study of children of divorce who now are parents.
Although I didn't realize it at the time, I've been doing a retrospective study my whole life.