منابع مشابه
External Validity of Knee Osteoarthritis Clinical Trials: A Systematic Review
©2015 Turkish League Against Rheumatism. All rights reserved. Randomized trials are often used as key evidence for detecting the effectiveness of treatments in knee osteoarthritis (KOA).1-3 However, for these trials to be clinically useful, trial participants should have similar characteristics with patients shown in clinical practices. To achieve this, trials need to be evaluated in terms of e...
متن کاملExternal validity of clinical trials in acute myocardial infarction.
BACKGROUND Patients enrolled in randomized clinical trials (RCTs) may not reflect those seen in real-life practice. Our goal was to compare patients eligible for enrollment but not enrolled in contemporary RCTs of reperfusion therapy with patients who would have been ineligible and also with patients with acute myocardial infarction (AMI) participating in RCTs. METHODS Consecutive patients wi...
متن کاملDo pragmatic trials trade-off internal validity for external validity?
Trials can be described as being on a design spectrum between highly explanatory (roughly, ‘Can the intervention work?’) to highly pragmatic (‘Does the intervention work in routine care?’). A criticism levelled at trials that take a pragmatic approach is that they sacrifice internal validity for external validity, i.e. there is a trade-off to be made. Proponents of pragmatic trials argue that t...
متن کاملInternal and External Validity in Clinical Research
dvances in clinical psychology critically depend on methods researchers use for investigating the causal relationships among variables. Research questions commonly include issues about the putative mechanisms associated with various forms of psychopathology (e.g., do dysfunctional beliefs cause depression?) and questions about the effects of treatments (e.g., does cognitive therapy cause a grea...
متن کاملRisk of pregnancy and external validity in clinical trials of emergency contraception.
OBJECTIVES To compare women who enroll in emergency contraception (EC) trials to those who decline and to understand why eligible women decline to participate. METHODS Data were collected from all women seeking EC (n = 5,787) at three clinics in the USA and UK during a period of nearly 1 year (from September 1997 to August 1998). The main outcome measures were pregnancy risk calculated by adj...
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ژورنال
عنوان ژورنال: Value in Health
سال: 1998
ISSN: 1098-3015
DOI: 10.1046/j.1524-4733.1998.130181.x