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

Search Page

Filters

My Custom Filters

Results by year

Table representation of search results timeline featuring number of search results per year.

Year Number of Results
2002 1
2004 1
2006 1
2025 0

Publication date

Text availability

Article attribute

Article type

Additional filters

Article Language

Species

Sex

Age

Other

Search Results

3 results

Results by year

Filters applied: . Clear all
Page 1
Principal stratification in causal inference.
Frangakis CE, Rubin DB. Frangakis CE, et al. Biometrics. 2002 Mar;58(1):21-9. doi: 10.1111/j.0006-341x.2002.00021.x. Biometrics. 2002. PMID: 11890317 Free PMC article.