The EQ-5D and SF-36 achieved mixed results in the quantitative testing against psychometric criteria .
The qualitative analysis suggests this is because they provide a very limited coverage of themes identified by people with mental health problems .
BACKGROUND Generic preference-based measures of health like the EQ-5D and SF-6D ( ® ) are increasingly being used in economic evaluation and outcome assessment .
However , there are concerns as to whether or not these generic measures are appropriate for use in people with mental health problems .
OBJECTIVES The EQ-5D and SF-36 ( ® ) ( including its derivatives the SF-12 ( ® ) and SF-6D ) were assessed using the psychometric criteria of validity and responsiveness using quantitative and qualitative methods .
Another aim was to estimate mapping functions between the EQ-5D and SF-6D and condition-specific measures , where appropriate .
Selecting and Appraising Studies for a Systematic Review
Systematic Review Series Series Editors : Cynthia Mulrow , MD , MSc Deborah Cook , MD , MSc The last article in this series outlined methods with which to search the literature for studies on the clinical question that generates a systematic review [ 1 ] . Herein , we discuss the subsequent steps of selecting and appraising  studies  for a review . Both of these steps involve important judgments that can influence the results of a review . In selecting studies , review ers judge the relevance of the studies to the review question . In appraising studies , review ers judge numerous features of design and analysis . Some of these judgments are easy to make ; others are more difficult and prone to error . To be confident in their decisions , review ers should use methods that are reliable ( the results do not change if the procedure is repeated ) , impartial ( not influenced by the study results ) , and explicit ( unambiguous ) [ 2 ] . These strategies for selection and appraisal are sensible , and they distinguish most systematic review s from most narrative review s. However , evidence to support the importance of some of the methods we suggest is either scant or conflicting ; readers are referred to the original research on these approaches for more details . Selecting Studies for Systematic Review s If review ers perform a comprehensive search of the literature using the methods described previously in this series [ 1 ] , they will probably have assembled a large sample of articles . This sample will include most ( ideally , all ) studies that are relevant to the review question ( that is , the sensitivity of the search will be high ) . Inevitably , because such a wide net is cast , articles not pertinent to the clinical question will be retrieved ( that is , the specificity of the search will be modest ) . Thus , the review ers ' next task is to sort through all of the potentially relevant articles and select those that will be included in the review . To do so , review ers adopt several of the tactics listed in Table 1 and Table 2 for planning and executing the selection process ( in effect , improving the specificity of the search ) ; these tactics are described below . Table 1 . Planning Study Selection Table 2 . Strategies for Selecting and Appraising Studies Begin with a Well-Built Clinical Question Review ers should ensure that the question for review includes the four elements of a well-built clinical question [ 3 , 4 ] : the patients of interest , the main interventions under investigation , the comparison interventions , and the clinical outcomes of interest . By including these four elements , review ers can better focus the selection process . Choose Selection Criteria That Fit the Clinical Question Consider a systematic review of the effectiveness of a drug treatment ( for example , a proton-pump inhibitor ) for patients with a particular disorder ( such as esophageal reflux ) . Review ers need to decide whether to include studies of patients with any symptoms of reflux , only those with classic symptoms , or only those in whom definitive diagnostic tests have confirmed the presence of reflux . In addition , review ers might choose to include studies of patients with different comorbid conditions ; patients from different demographic or geographic or cultural background s ; or patients from different health systems , such as inpatient or community population s. Similarly , review ers should use selection criteria that reflect the main and comparison interventions of interest . In our esophageal reflux example , review ers would need to decide whether to include studies of a particular drug or studies of all agents in that drug 's class and whether to include studies of any dose and regimen or only studies with a specific regimen . For the comparison interventions , the review ers would decide whether to include studies that compare the experimental drug with alternate treatments ( such as antacids or histamine-2-receptor antagonists ) , with placebo , or with both . For the clinical outcomes , review ers have analogous tasks of defining the outcomes and translating them into criteria . In our example , the review ers would start by listing each clinical outcome ( for example , whether the outcome was endoscopic or clinical and whether it focused on cure or persistence ) and then decide whether to include studies that reported any outcome or only those with certain clinical ly important outcomes ( such as improvement in symptoms at 1 year ) . After thoroughly considering each element of the review question , review ers compile a set of explicit selection criteria . When these criteria are not explicit , the results of the review are more prone to error [ 5 , 6 ] . Reporting the selection criteria used in a review is extremely important to readers because the criteria indicate the relevance of the review to the readers ' clinical practice . Specify the Types of Study Design To Be Included After creating selection criteria that appropriately reflect the review question , review ers should consider which study design s to include . Ideally , review ers choose study design s that are most likely to produce valid results . For example , to answer questions about therapy or harm , review ers may want to include r and omized trials [ 7 ] because they provide more accurate estimates of benefit or harm than do cohort studies , casecontrol studies , and case series [ 8 ] . In reality , however , r and omized trials may not be conducted to address questions of harm [ 9 ] . Therefore , review ers need to consider which study design s are likely to be available to answer their question ; this information may necessitate modification of originally conceptualized selection criteria to incorporate observational ( nonexperimental ) studies . Specify Criteria Related to Type and Form of Publication Review ers also need to consider issues related to type and form of publication . Ideally , all of the relevant studies would be published as peer- review ed journal articles . However , some completed studies may be published only as abstract s , in non-peer- review ed form , or not at all . Review ers decide whether to include these incompletely reported studies when planning their literature search . By including all articles in various stages of publication and subjecting them to rigorous critical appraisal , review ers minimize the threat of publication bias ( the preferential reporting of studies with positive results ) [ 10 - 12 ] , which could generate misleading review s. Other studies may be reported more than once . To avoid over-representing duplicate studies in the review , investigators should plan to look for and exclude duplicate publications [ 13 ] . Finally , because studies may be published in different language s and because excluding studies published in different language s may bias the results of review s [ 14 , 15 ] , articles should be included , as appropriate , regardless of the language of publication ( translating as necessary ) . Limited time and re sources , however , may preclude such an approach . Construct and Pretest Selection Forms After deciding on selection criteria , review ers can prepare customized forms that contain checklists of the selection criteria ( Figure 1 ) . Using these forms can simplify the selection process , increase reliability , and provide a record of the judgments made about each study . After drafting form prototypes , review ers pretest these forms for clarity , ease of application , and reliability . To pretest the forms , two or more independent review ers typically apply them to a r and om sample of studies identified by the literature search . Review ers compare their results to identify sources of ambiguity and then revise the forms accordingly . If the revisions are substantial , this process may need to be repeated before the forms can be used . Figure 1 . Example of a form that might be developed for the selection of studies for a systematic review evaluating the efficacy of -blockers for secondary prevention of variceal bleeding .  Write a Detailed Protocol Having a selection protocol as part of a larger protocol for the entire review helps review ers in two ways . First , it provides a document that explicitly states the review question and the selection criteria , making the process accountable . Review ers can later return to the protocol for guidance in resolving disagreements about article selection . Second , the selection protocol identifies what work will be done , by whom , in what manner , when , and for what reason ; thus , it provides a mode of communication within the review team . When review ers have a very large sample of studies from which to select , they can simplify this task by review ing all of the titles , then the abstract s , and then the full articles , excluding studies that do not meet one or more selection criteria at each step . In doing so , review ers should record ( on the selection forms ) the reasons for exclusion . After review ers have selected studies for the systematic review , they will move to the next task of critical appraisal . This procedure also requires careful planning . Appraising Studies for Systematic Review s Review ers appraise the studies selected for review with three objectives in mind : 1 ) to underst and the validity of the studies , 2 ) to uncover reasons for differences among study results other than chance , and 3 ) to provide readers with sufficient information with which to judge for themselves the applicability of the systematic review to their clinical practice . To achieve these goals , review ers use the strategies outlined in Table 2 and Table 3 to carefully reexamine many important features of the primary studies . Table 3 . Planning Study Appraisal Examine Important Clinical Features Although the selection criteria for a systematic review define the population , interventions , and outcomes of interest , the appraisal process involves a detailed assessment of the patients ( for example , high , medium , or low risk ) , the study interventions ( for example , frequency , degree , and duration ) , and the outcome measurements ( for example , definitions and degree of surveillance )
The EQ-5D and SF-36 achieved mixed results in the quantitative testing against psychometric criteria .
The qualitative analysis suggests this is because they provide a very limited coverage of themes identified by people with mental health problems .
BACKGROUND Generic preference-based measures of health like the EQ-5D and SF-6D ( ® ) are increasingly being used in economic evaluation and outcome assessment .
However , there are concerns as to whether or not these generic measures are appropriate for use in people with mental health problems .
OBJECTIVES The EQ-5D and SF-36 ( ® ) ( including its derivatives the SF-12 ( ® ) and SF-6D ) were assessed using the psychometric criteria of validity and responsiveness using quantitative and qualitative methods .
Another aim was to estimate mapping functions between the EQ-5D and SF-6D and condition-specific measures , where appropriate .