Trials are based on past studies and what has been learned in the laboratory.

The primary problem in past studies was the limitiations on available data.

Past studies have analyzed the elderly primarily as a group 65 and over.

Past studies on the effectiveness of burning may have given researchers false hope.

Past studies in this country have indicated a slight preference for boys.

A past study has given the content industries reason to hope that a mere warning will be enough to get the job done.

Past studies found that 10 percent to 20 percent of patients had complications while they were in the hospital.

It might not tell much by itself, but I think it says more when included with past cognitive studies.

Past studies suggested that "long-term use of the drugs could stunt children's growth."

Past studies of reading concentrated on the text and paid little attention to the reader who was engaged with it.