The phrase "outcomes studies" is usually used to describe those studies whe
re outcome is assessed in large cohorts of patients, often using data from
administrative databases, They are used to determine the role and impact of
variations in the structure and process of health care delivery play in ro
utine practice, Optimally, outcome should be assessed in terms of measures
that are important to patients (e.g., quality of life). More often, clinica
lly relevant outcome measures are lacking, and outcome is measured in terms
of mortality, morbidity, and length of hospital stay, Although the outcome
s movement continues to expand and much valuable information can be learned
from this type of study, there are limitations. These studies are essentia
lly observational and most often are performed using databases set up for o
ther purposes. Thus data may be incomplete and incorrect. Moreover, they ca
nnot assess the impact of patient preferences on outcome, The term outcomes
studies has also been applied to small area variation and volume outcome s
tudies.