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"internal validity"

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How Individual Studies Consider Applicability. Studies often do not report on factors needed to judge applicability. Increased use of CONSORT diagrams helps, but deficiencies remain. Only a small number of studies are designed with applicability in mind. Most trials are efficacy trials that maximize internal validity at the expense of applicability. CONSORT = Consolidated Standards of Reporting Trials.
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How Individual Studies Consider Applicability

Presentation: Assessing Applicability
Keywords: applicability | transparency | efficacy trials | internal validity | outcomes
Judge Applicability and Strength of Evidence Separately. Applicability is best reported separately from quality or strength of evidence. Internal validity concerns are not altered by changes in perspective, but applicability is. Some evidence hierarchies (GRADE) consider applicability “or directness” when assessing the quality of evidence. For systematic reviews in which multiple perspectives (clinician, patient, policymaker) are considered, applicability should be assessed separately.
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Judge Applicability and Strength of Evidence Separately

Presentation: Assessing Applicability
Keywords: applicability | strength of evidence | internal validity | GRADE
Population and Applicability: Examples. In a trial of women with osteoporosis, only 4,000 of the 54,000 women screened were enrolled; the enrollees were younger, healthier, and more adherent to therapy than is typical of women with osteoporosis. A trial of etanercept for juvenile diabetes excluded patients with side effects during an active run-in period; the trial found a low incidence of adverse events. Clinical trials used to inform Medicare decisions enrolled patients who were younger (60 vs. 75 years of age) and more often male (75 vs. 42%) than is typical of Medicare patients with cardiovascular disease.
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Population and Applicability: Examples

Presentation: Assessing Applicability
Keywords: applicability | population | internal validity | exclusion criteria | inclusion criteria
Outcomes and Applicability: Examples. Trials of biologics for rheumatoid arthritis that used radiographic progression rather than symptom evaluations as an outcome measure. Trials comparing cyclooxygenase-2 inhibitors and nonsteroidal antiinflammatory drugs that used endoscopy-evaluated ulceration rather than symptomatic ulcers as an outcome measure.
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Outcomes and Applicability: Examples

Presentation: Assessing Applicability
Keywords: outcomes | applicability
Strength of Evidence. Why should grading of the strength of evidence and assessment of applicability be carried out separately? A. Strength of evidence grading and applicability assessment are essentially the same. B. Studies using strong methods can show that an intervention is superior to a control therapy in a study population, but it may or may not work in actual practice. C. Strength of evidence grading is primarily associated with assessing the external validity, whereas applicability assessment is concerned with internal validity.
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Strength of Evidence

Presentation: Assessing Applicability Quiz
What Is Quality Assessment? Definition of quality: “[T]he extent to which all aspects of a study’s design and conduct can be shown to protect against systematic bias, nonsystematic bias, and inferential error.” (Lohr & Carey, 1999). Considered to be synonymous with internal validity. Relevant for individual studies. Distinct from assessment of risk of bias for a body of evidence.
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What Is Quality Assessment?

Presentation: Assessing the Quality of Individual Studies
Keywords: quality assessment | internal validity
Consider the Contribution of an Individual Study to the Body of Evidence. This slide shows how characteristics of the individual study relate to domains evaluating the strength of the body of evidence. Each characteristic of the individual study is linked by an arrow to a domain for the strength of the body of evidence. The slide shows that the quality or internal validity of a study (i.e., limitations of study design and conduct) is one of several ways in which an individual study can contribute to the body of evidence. When evaluating the strength of the entire body of evidence, the quality of the study and the type of design influence the evaluation of the risk of bias for the entire body of evidence. The direction and magnitude of the results influence considerations of consistency of the body of evidence. The size of the study could result in nonsystematic or random error; it influences considerations of precision of the body of evidence. The relevance of the results to the key questions influences the evaluation of directness of the body of evidence. The relevance of the study sample to the population(s) of interest influences the assessment of applicability or generalizability of the body of evidence.
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Consider the Contribution of an Individual Study to the Body of Evidence

Presentation: Assessing the Quality of Individual Studies
Keywords: internal validity | study design | body of evidence | key questions | applicability | generalizability
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Introduction

Presentation: Comparator Selection in Observational Comparative Effectiveness Research
Keywords: background | comparator choice | confounding | selection bias | internal validity
This figure presents an overview of the steps in the systematic review process. The first step, the preparation of the topic, requires refinement of the topic and development of an analytic framework. The second step is to search for and select studies for inclusion, which involves identifying study eligibility criteria, searching for relevant studies, and selecting evidence for inclusion. The third step is to abstract data, which involves extracting data from individual studies. The fourth step is to analyze and synthesize studies, which involves assessing the quality of individual studies, assessing applicability, presenting findings in tables, synthesizing quantitative data, and grading the strength of evidence. The final step is to report the systematic review. This module focuses on grading the strength of evidence.
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Systematic Review Process Overview

Presentation: Grading Strength of Evidence
Four Required Domains: Risk of Bias. Concerns both study design and study conduct for individual studies, rated by usual methods. Assesses the aggregate quality of studies within each major study design and integrates those assessments into an overall risk-of-bias score. Risk-of-bias scores: High—lowers strength-of-evidence grade. Medium. Low—raises strength-of-evidence grade.
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Four Required Domains: Risk of Bias

Presentation: Grading Strength of Evidence
Keywords: risk of bias | internal validity | study design | body of evidence | Evidence-based Practice Center | meta-analysis | strength of evidence
Strength of Evidence Versus Quality. Is grading the strength of evidence the same as rating the quality of studies? A. Yes, they are the same thing. B. No, but you can grade strength of evidence at the same time that you rate the quality of the individual studies. C. No, you can grade the strength of evidence only after you have rated the quality of individual studies.
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Strength of Evidence Versus Quality

Presentation: Grading Strength of Evidence Quiz
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Study Design and Analysis (1 of 2)

Presentation: Outcome Definition and Measurement in Observational Comparative Effectiveness Research
Keywords: study design | analysis | bias | misclassification | validation | adjudication
Pages: [1] 2 Next
 
 
 
 
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