External Validity: The Next Step for Systematic Reviews?

2016 ◽  
Vol 41 (4) ◽  
pp. 283-325 ◽  
Author(s):  
Sarah A. Avellar ◽  
Jaime Thomas ◽  
Rebecca Kleinman ◽  
Emily Sama-Miller ◽  
Sara E. Woodruff ◽  
...  
Keyword(s):  
Systematic Review ◽  
Systematic Reviews ◽  
External Validity ◽  
Home Visiting ◽  
Evaluation Research ◽  
Internal Validity ◽  
Reporting Guidelines ◽  
Sample Characteristics ◽  
Statistical Representativeness

Background: Systematic reviews—which identify, assess, and summarize existing research—are usually designed to determine whether research shows that an intervention has evidence of effectiveness, rather than whether an intervention will work under different circumstances. The reviews typically focus on the internal validity of the research and do not consistently incorporate information on external validity into their conclusions. Objectives: In this article, we focus on how systematic reviews address external validity. Methods: We conducted a brief scan of 19 systematic reviews and a more in-depth examination of information presented in a systematic review of home visiting research. Results: We found that many reviews do not provide information on generalizability, such as statistical representativeness, but focus on factors likely to increase heterogeneity (e.g., numbers of studies or settings) and report on context. The latter may help users decide whether the research characteristics—such as sample demographics or settings—are similar to their own. However, we found that differences in reporting, such as which variables are included and how they are measured, make it difficult to summarize across studies or make basic determinations of sample characteristics, such as whether the majority of a sample was unemployed or married. Conclusion: Evaluation research and systematic reviews would benefit from reporting guidelines for external validity to ensure that key information is reported across studies.

Biomedical conferences’ author instructions rarely mention guidelines for reporting abstracts of trials and systematic reviews

2020 ◽  
Vol 9 (2) ◽  
pp. 83-91
Author(s):  
Lenko Saric ◽  
Svjetlana Dosenovic ◽  
Jakov Mihanovic ◽  
Livia Puljak
Keyword(s):  
Systematic Review ◽  
Randomized Controlled Trial ◽  
Systematic Reviews ◽  
Controlled Trial ◽  
Reporting Guidelines ◽  
Randomized Controlled ◽  
Meta Analyses

Aim: To analyze whether instructions for authors of biomedical conference abstracts mention guidelines for writing randomized controlled trial and systematic review abstracts and to evaluate reasons for their absence from instructions. Materials & methods: We analyzed instructions for authors of biomedical conferences advertized in 2019 and assessed whether they mentioned Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Abstracts and Consolidated Standards of Reporting Trials for Abstracts guidelines. We surveyed contact persons from abstract/publication committees of selected conferences to analyze why relevant guidelines were missing. Results: Instructions for abstracts were available for 819 conferences. Only two (0.2%) had reporting instructions for randomized controlled trial/systematic review authors. Almost half of the contacted conference organizers whose response we received were not aware of Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Abstracts and Consolidated Standards of Reporting Trials for Abstracts guidelines. Conclusion: Conference organizers do not require and are not familiar enough with reporting guidelines.

scholarly journals Acupuncture for Low Back Pain: An Overview of Systematic Reviews

2015 ◽  
Vol 2015 ◽  
pp. 1-18 ◽  
Author(s):  
Lizhou Liu ◽  
Margot Skinner ◽  
Suzanne McDonough ◽  
Leon Mabire ◽  
George David Baxter
Keyword(s):  
Low Back Pain ◽  
Back Pain ◽  
Systematic Reviews ◽  
External Validity ◽  
Internal Validity ◽  
Sham Acupuncture ◽  
Functional Improvement ◽  
Favorable Effect ◽  
Low Back ◽  
Short Term

Objective. As evidence of the effectiveness of acupuncture for low back pain (LBP) is inconsistent, we aimed to critically appraise the evidence from relevant systematic reviews.Methods. Systematic reviews of randomized controlled trials (RCTs) concerning acupuncture and LBP were searched in seven databases. Internal validity and external validity of systematic reviews were assessed. Systematic reviews were categorized and high quality reviews assigned greater weightings. Conclusions were generated from a narrative synthesis of the outcomes of subgroup comparisons.Results. Sixteen systematic reviews were appraised. Overall, the methodological quality was low and external validity weak. For acute LBP, evidence that acupuncture has a more favorable effect than sham acupuncture in relieving pain was inconsistent; it had a similar effect on improving function. For chronic LBP, evidence consistently demonstrated that acupuncture provides short-term clinically relevant benefits for pain relief and functional improvement compared with no treatment or acupuncture plus another conventional intervention.Conclusion. Systematic reviews of variable quality showed that acupuncture, either used in isolation or as an adjunct to conventional therapy, provides short-term improvements in pain and function for chronic LBP. More efforts are needed to improve both internal and external validity of systematic reviews and RCTs in this area.

scholarly journals Partially randomised patient preference trials as an alternative design to randomised controlled trials: systematic review and meta-analyses

BMJ Open ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. e031151 ◽  
Author(s):  
Karin A Wasmann ◽  
Pieta Wijsman ◽  
Susan van Dieren ◽  
Willem Bemelman ◽  
Christianne Buskens
Keyword(s):  
Systematic Review ◽  
External Validity ◽  
Randomised Controlled Trials ◽  
Primary Outcome ◽  
Internal Validity ◽  
Controlled Trials ◽  
Randomised Controlled ◽  
Meta Analyses ◽  
Lost To Follow Up

ObjectiveRandomised controlled trials (RCT) are the gold standard to provide unbiased data. However, when patients have a treatment preference, randomisation may influence participation and outcomes (eg, external and internal validity). The aim of this study was to assess the influence of patients’ preference in RCTs by analysing partially randomised patient preference trials (RPPT); an RCT and preference cohort combined.DesignSystematic review and meta-analyses.Data sourcesMEDLINE, Embase, PsycINFO and the Cochrane Library.Eligibility criteria for selecting studiesRPPTs published between January 2005 and October 2018 reporting on allocation of patients to randomised and preference cohorts were included.Data extraction and synthesisTwo independent reviewers extracted data. The main outcomes were the difference in external validity (participation and baseline characteristics) and internal validity (lost to follow-up, crossover and the primary outcome) between the randomised and the preference cohort within each RPPT, compared in a meta-regression using a Wald test. Risk of bias was not assessed, as no quality assessment for RPPTs has yet been developed.ResultsIn total, 117 of 3734 identified articles met screening criteria and 44 were eligible (24 873 patients). The participation rate in RPPTs was >95% in 14 trials (range: 48%–100%) and the randomisation refusal rate was >50% in 26 trials (range: 19%–99%). Higher education, female, older age, race and prior experience with one treatment arm were characteristics of patients declining randomisation. The lost to follow-up and cross-over rate were significantly higher in the randomised cohort compared with the preference cohort. Following the meta-analysis, the reported primary outcomes were comparable between both cohorts of the RPPTs, mean difference 0.093 (95% CI −0.178 to 0.364, p=0.502).ConclusionsPatients’ preference led to a substantial proportion of a specific patient group refusing randomisation, while it did not influence the primary outcome within an RPPT. Therefore, RPPTs could increase external validity without compromising the internal validity compared with RCTs.PROSPERO registration numberCRD42019094438.

Furthering Dissemination and Implementation Research

2017 ◽  
Author(s):  
Lawrence W. Green ◽  
Mona Nasser
Keyword(s):  
Systematic Reviews ◽  
Implementation Research ◽  
External Validity ◽  
Evidence Based Practice ◽  
Internal Validity ◽  
Implementation Process ◽  
Dissemination And Implementation ◽  
Evidence Based ◽  
Evidence Based Practices ◽  
Dissemination And Implementation Research

This chapter raises questions about the reliability of much “evidence-based practice” disseminated from the original studies and systematic reviews of those studies, insofar as they were often conducted and reviewed with inadequate attention to external validity. Important issues are raised for dissemination and implementation researchers. Indeed, the pressure on investigators to provide for increasingly rigorous controls on threats to internal validity, and to exclude studies that fall below standards for internal validity, has made many such sources of evidence more suspect in their external validity and less credible to the practitioners or policymakers who would adopt them. Greater attention is needed to ways to incorporate considerations of external validity into studies and in systematic reviews of studies to produce more generalizable evidence, and greater attention to practice-based evidence that can complement the more formal evidence-based practices in the process of implementing and evaluating the dissemination and implementation process

scholarly journals Updating guidance for reporting systematic reviews: development of the PRISMA 2020 statement

2020 ◽  
Author(s):  
Matthew James Page ◽  
Joanne McKenzie ◽  
Patrick Bossuyt ◽  
Isabelle Boutron ◽  
Tammy Hoffmann ◽  
...  
Keyword(s):  
Systematic Review ◽  
Systematic Reviews ◽  
Development Process ◽  
Reporting Guidelines ◽  
Systematic Review Methodology ◽  
Convenience Sample ◽  
Journal Editors ◽  
Prisma Statement ◽  
Meta Analyses

Background: The Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) Statement, published in 2009, aimed to help systematic reviewers prepare a transparent report of their review. Advances in systematic review methodology and terminology over the last decade necessitated an update to the guideline. A detailed description of the updating process may provide a useful roadmap for others embarking on a similar initiative.Objectives: To (i) describe the processes used to update the PRISMA 2009 statement for reporting systematic reviews, (ii) present results of a survey conducted to inform the update, (iii) summarise decisions made at the PRISMA update meeting, and (iv) describe and justify changes made to the guideline.Methods: We reviewed 60 documents with reporting guidance for systematic reviews to generate suggested modifications to the PRISMA 2009 statement. We invited 220 systematic review methodologists and journal editors to complete a survey about the suggested modifications. The results of these projects were discussed at a 21-member in-person meeting. Following the meeting, we drafted the PRISMA 2020 statement and refined it based on feedback from co-authors and a convenience sample of 15 systematic reviewers. Results: The review of 60 documents with reporting guidance for systematic reviews resulted in a bank of 221 unique reporting items and revealed that all topics addressed by the PRISMA 2009 statement could be modified or supplemented with additional guidance. Of the 110 respondents to the survey, more than 66% recommended keeping six of the 27 PRISMA 2009 checklist items as they were and modifying 15 of the checklist items using wording suggested by us; there was no consensus on what to do with the remaining six items. Attendees at the in-person meeting supported the revised wording for several items but suggested rewording for most items to enhance clarity, and further refinements were made over six drafts of the guideline. Conclusions: The PRISMA 2020 statement consists of updated reporting guidance for systematic reviews and reflects advances over the last decade in methods to identify, select, appraise and synthesise studies. We hope that providing this detailed description of the development process will enhance the acceptance and uptake of the guideline and assist those developing and updating future reporting guidelines.

scholarly journals Systematic Review and Meta-Analysis of Randomised, Other-than-Placebo Controlled, Trials of Individualised Homeopathic Treatment

Homeopathy ◽  
2018 ◽  
Vol 107 (04) ◽  
pp. 229-243 ◽  
Author(s):  
Susanne Ulbrich-Zürni ◽  
Petter Viksveen ◽  
E. Roberts ◽  
Elizabeth Baitson ◽  
Lynn Legg ◽  
...  
Keyword(s):  
Systematic Review ◽  
High Risk ◽  
External Validity ◽  
Comparative Effectiveness ◽  
Meta Analysis ◽  
Internal Validity ◽  
Risk Of Bias ◽  
Controlled Trials ◽  
Homeopathic Treatment ◽  
Pragmatic Study

Background This study focuses on randomised controlled trials (RCTs) of individualised homeopathic treatment (IHT) in which the control (comparator) group was other than placebo (OTP). Aims To determine the comparative effectiveness of IHT on health-related outcomes in adults and children for any clinical condition that has been the subject of at least one OTP-controlled trial. For each study, to assess the risk of bias and to determine whether its study attitude was predominantly ‘pragmatic’ or ‘explanatory’. Methods Systematic review. For each eligible trial, published in the peer-reviewed literature up to the end of 2015, we assessed its risk of bias (internal validity) using the seven-domain Cochrane tool, and its relative pragmatic or explanatory attitude (external validity) using the 10-domain PRECIS tool. We grouped RCTs by whether they examined IHT as an alternative treatment (study design Ia), adjunctively with another intervention (design Ib), or compared with a no-intervention group (design II). For each RCT, we identified a ‘main outcome measure’ to use in meta-analysis: ‘relative effect size’ was reported as odds ratio (OR; values >1 favouring homeopathy) or standardised mean difference (SMD; values < 0 favouring homeopathy). Results Eleven RCTs, representing 11 different medical conditions, were eligible for study. Five of the RCTs (four of which in design Ib) were judged to have pragmatic study attitude, two were explanatory, and four were equally pragmatic and explanatory. Ten trials were rated ‘high risk of bias’ overall: one of these, a pragmatic study with design Ib, had high risk of bias solely regarding participant blinding (a bias that is intrinsic to such trials); the other trial was rated ‘uncertain risk of bias’ overall. Eight trials had data that were extractable for analysis: for four heterogeneous trials with design Ia, the pooled OR was statistically non-significant; collectively for three clinically heterogeneous trials with design Ib, there was a statistically significant SMD favouring adjunctive IHT; in the remaining trial of design 1a, IHT was non-inferior to fluoxetine in the treatment of depression. Conclusions Due to the low quality, the small number and the heterogeneity of studies, the current data preclude a decisive conclusion about the comparative effectiveness of IHT. Generalisability of findings is limited by the variable external validity identified overall; the most pragmatic study attitude was associated with RCTs of adjunctive IHT. Future OTP-controlled trials in homeopathy should aim, as far as possible, to promote both internal validity and external validity.

Regression Discontinuity and Beyond

2018 ◽  
Vol 39 (1) ◽  
pp. 91-108 ◽  
Author(s):  
Coady Wing ◽  
Ricardo A. Bello-Gomez
Keyword(s):  
Treatment Effect ◽  
External Validity ◽  
Regression Discontinuity ◽  
Statistical Tests ◽  
Evaluation Research ◽  
Internal Validity ◽  
New Methods ◽  
Local Selection ◽  
Data Requirements ◽  
High Internal Validity

Treatment effect estimates from a regression discontinuity design (RDD) have high internal validity. However, the arguments that support the design apply to a subpopulation that is narrower and usually different from the population of substantive interest in evaluation research. The disconnect between RDD population and the evaluation population of interest suggests that RDD evaluations lack external validity. New methodological research offer strategies for studying and sometimes improving external validity in RDDs. This article examines four techniques: comparative RDD, covariate matching RDD, treatment effect derivatives, and statistical tests for local selection bias. The goal of the article is to help evaluators understand the logic, assumptions, data requirements, and reach of the new methods.

The Clinical Utility and Assessment of Renal Biomarkers in Acute Kidney Injury After Abdominal Endovascular Aneurysm Repair. A Systematic Review

2020 ◽  
Vol 25 (44) ◽  
pp. 4695-4701 ◽  
Author(s):  
Georgios Karaolanis ◽  
Zachary F. Williams ◽  
Chris Bakoyiannis ◽  
Dimitrios Hadjis ◽  
Mitchell W. Cox ◽  
...  
Keyword(s):  
Systematic Review ◽  
Acute Kidney Injury ◽  
Systematic Reviews ◽  
Clinical Utility ◽  
Binding Protein ◽  
Endovascular Aneurysm Repair ◽  
Kidney Injury ◽  
Aortic Aneurysms ◽  
Renal Biomarkers ◽  
Aneurysm Repair

: The widespread adoption of endovascular aneurysm repair (EVAR) for abdominal aortic aneurysms (AAA) is due to the obvious advantages of the procedure compared to the traditional open repair. However, these advantages have to be weighed against the increased risk of renal dysfunction with EVAR. The evaluation of the perioperative renal function after EVAR has been hampered by the lack of sensitive and specific biochemical markers of acute kidney injury (AKI). The purpose of this study was to summarize all novel renal biomarkers and to evaluate their clinical utility for the assessment of the kidney function after EVAR. A systematic review of the current literature, as the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement guidelines, was performed to identify relevant studies with novel renal biomarkers and EVAR. Pubmed and Scopus databases were systemically searched. Studies reporting on thoracic endovascular aortic repair (TEVAR), case reports, case series, letters to the editor, and systematic reviews were excluded. Neutrophil-Gelatinase-Associated Lipocalin, Cystatin C, Liver-type fatty-acid-binding protein were the most common among the eligible studies while Interleukin-18, Retinol binding protein, N-acetyle-b-D-glucosaminidase and microalbumin have a sparse appearance in the literature. These biomarkers have been assessed in plasma as well as urine samples with each sample material having its own advantages and drawbacks. Which of these biomarkers has the most potential for assessing postoperative renal failure after EVAR, remains to be proved. The few studies presented in the literature show the potential clinical utility of these biomarkers, but larger studies with longer follow-up are required to determine the precise relationship between these biomarkers and postoperative acute kidney injury.

Sign in / Sign up

Export Citation Format

Share Document