observational studies造句

For some of these questions, observational studies are the best we are going to get.

But these were mostly based on observational studies, which can be misleading.

We have more than 10 years of experience in medical research worldwide which include phase II - phase IV clinical trials and non-interventional observational studies.

These generally have been observational studies, and while their conclusions are useful for developing theories, they cannot prove cause-and-effect relationships.

Previous work by Dr Ioannidis, on six highly cited observational studies, showed that conclusions from five of them were later refuted.

There were also hints that aspirin may help prevent some cancers. But these were mostly based on observational studies, which can be misleading.