Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
Comment
. 1997 Mar;8(2):219-20.

Confounding by indication and past clinical trials

M Porta
  • PMID: 9229221
Comment

Confounding by indication and past clinical trials

M Porta. Epidemiology. 1997 Mar.
No abstract available

PubMed Disclaimer

Comment on

  • Confounding by indication.
    Walker AM. Walker AM. Epidemiology. 1996 Jul;7(4):335-6. Epidemiology. 1996. PMID: 8793355 No abstract available.

MeSH terms