The study shows an association but is not designed to show cause and effect.

But the new study was not designed to look for such differences.

The study was not designed to test the theory among people under 65.

The study was designed to test lead levels in five groups of housing.

But the study was not designed to test that theory.

The reason for the differences may be due to the way the studies were designed.

Data from studies specifically designed to answer this question are expected within the next few years.

But these results have been questioned because the study wasn't designed well.

Third, was the new study designed in a way that would give a meaningful answer to the research question?

Some researchers question these results because they think the studies were poorly designed.