I propose that effectiveness studies might be conducted in an infrastructur
e consisting of groups of evidence-based practitioners. Clinicians using ev
idence-based approacher to clinical work have well-developed systems for co
llecting outcome data that are fully integrated into routine clinical pract
ice, a mode of work that ir ideally suited to effectiveness studies. A form
al, National Institutes of Health-funded structure might be developed to su
pport clinical practice infrastructures to host or conduct effectiveness st
udies, These clinical practice infrastructures would speed the disseminatio
n of evidence-based methods of clinical practice. Clinical practice infrast
ructures would also enhance clinicians' ability to make contributions to re
search. In particular, evidence-based practitioners use empirically-based m
ethods of hypothesis testing and session-by-session outcome monitoring that
are not well represented in many of the protocols that are evaluated in ra
ndomized controlled trials.