RT Journal
A1 Radford MJ, Foody JM
T1 HOw do observational studies expand the evidence base for therapy?
JF JAMA
JO JAMA
YR 2001
FD September 12
VO 286
IS 10
SP 1228
OP 1230
DO 10.1001/jama.286.10.1228
UL http://dx.doi.org/10.1001/jama.286.10.1228
AB 
The impressive advances in cardiovascular therapy during the last several
decades owe a great deal to randomized trials.1
The foundation for 21st-century cardiovascular care has been laid, therapy
by therapy, through the disciplined application of randomized trial methodology
to important scientific insights and therapeutic uncertainties. The random
assignment of patients to receive one care strategy or therapy vs another
has allowed investigators to separate consistent therapeutic efficacy "signals"
from the "noise" of patient variability and physician bias.