in drug design

Quantitative structure–activity relationships (QSAR) are mathematical
relationships linking chemical structure and pharmacological activity
in a quantitative manner for a series of compounds. Methods which
can be used in QSAR include various regression and pattern
recognition techniques.

QSAR is often taken to be equivalent to chemometrics or multivariate
statistical data analysis. It is sometimes used in a more limited sense
as equivalent to Hansch analysis. QSAR is a subset of the more
general term SPC.

Source:

PAC, 1997, *69*, 1137*
(Glossary of terms used in computational drug design (IUPAC Recommendations 1997))
* on page 1149