***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Data from 12 independently design ed and conducted r and omized trials of behavioral interventions for hypertension , consisting principally of variants of relaxation and biofeedback therapies , were aggregated to assess current progress of research in this area . Meta-analytical methods revealed a statistically significant decrease in diastolic blood pressure for nonmedicated patients at the end of intervention . No significant improvement was detected in medicated patients , but potential differential effectiveness of prescribed medications and differences in compliance among patients prohibits separation of changes due to behavioral treatments alone . The need to devise criteria for selection of patients , and to establish the most appropriate patient-treatment match is emphasized In clinical measurement comparison of a new measurement technique with an established one is often needed to see whether they agree sufficiently for the new to replace the old . Such investigations are often analysed inappropriately , notably by using correlation coefficients . The use of correlation is misleading . An alternative approach , based on graphical techniques and simple calculations , is described , together with the relation between this analysis and the assessment of repeatability Summary . R and omized controlled trials are increasingly used t o assess clinical practice s in obstetrics and gynaecology . The strength of these studies is that they usually address the issue of selection bias satisfactorily . Yet , as with any form of scientific investigation , the r and omized controlled trial has inherent limitations and is subject to flaws in its conduct . Using basic method ological criteria , this report assesses the quality of the four published controlled trials in which a policy of routine imaging ultrasonography in pregnancy  was compared with a more restrictive policy . In addition , a pooled analysis using data from all four trials was conducted to illustrate how increasing the sample size may reveal differences between the two policies which remain undetected in trials using small sample s. The research ers in these studies reached different conclusions as to the effectiveness of routine ultrasound screening .  Taken together , these four trials provide valuable information about routine ultrasound screening but fail to demonstrate adequately the usefulness of  imaging ultrasound  as a screening procedure for all pregnant women . The assessment criteria presented here could be used by investigators , editors , referees and other readers as a guideline for assessing the quality of therapeutic studies upon which clinical practice should be based We examined existing evidence concerning the relative efficacy of various vasodilator agents in chronic congestive heart failure . Only r and omized placebo-controlled trials with clinical end points and treatment duration s of four weeks or more were selected from an exhaustive search of the English- language medical literature . Twenty-eight trials involving 1976 patients were found . Treatment duration s of the trials varied from one month to two years . Patients with symptomatic heart failure despite digitalis and diuretic therapy were studied ; most were middle-aged men and approximately half had coronary artery disease . Results of the trials were appraised by three independent observers , and mortality and functional status outcomes were pooled in a meta- analysis . All vasodilator agents except hydralazine hydrochloride were associated with improvements in functional status . Angiotensin converting-enzyme inhibitors were the only agents associated with both decreased mortality ( odds ratio , 0.51 ; 95 % confidence interval , 0.34 to 0.75 ) and improved functional status ( odds ratio , 4.53 ; 95 % confidence interval , 3.46 to 5.92 ) . The optimal timing for initiation of these agents was not established Assessing the quality of r and omized controlled trials ( RCTs ) is important and relatively new . Quality gives us an estimate of the likelihood that the results are a valid estimate of the truth . We present an annotated bibliography of scales and checklists developed to assess quality . Twenty-five scales and nine checklists have been developed to assess quality . The checklists are most useful in providing investigators with guidelines as to what information should be included in reporting RCTs . The scales give readers a quantitative index of the likelihood that the reported methodology and results are free of bias . There are several shortcomings with these scales . Future scale development is likely to be most beneficial if questions common to all trials are assessed , if the scale is easy to use , and if it is developed with sufficient rigor 
    Output:
    
AMSTAR has good agreement , reliability , construct validity , and feasibility .