Critical Appraisal วิจารณญาณ

โครงการการจัดการปัจจัยเสี่ยงและปัจจัยเอื้อต่อสุขภาพ ตามผลการวิเคราะห์ภาระโรคในพื้นที่เขตสุขภาพที่ 12 Critical Appraisalวิจารณญาณ ดร.นพ.วรสิทธิ์ ศรศรีวิชัย มูลนิธิสุขภาพภาคใต้ สถาบันการจัดการระบบสุขภาพภาคใต้ มหาวิทยาลัยสงขลานครินทร์

Research Objectives • Is there a clear statement of research objectives and/or hypotheses? • Does the study address a question that has clinical and/or public health relevance?

Study Design • Does the study design appropriate for the objectives/hypotheses? • Does the study represent an advance over prior approach? How?

Outcome Variable • What is the outcome? • Is the outcome variable relevant to the objectives? • What criteria are used to define the outcome? • Is the determination of the presence or absence of disease accurate?

Independent Variable • How many exposure variables are being studied? • How many potential confounders are considered, and why? • How is presence or absence of exposure determined? Is the assessment of exposure likely to be precise and accurate? • Is there attempt to quantify the amount or duration of exposure?

Method of Analysis • Are the statistical methods used in the analysis appropriate to the type of variables being studied? • Is the sample size adequate to answer the research question? • Have the assumption underlying the statistical tests been met? • Has chance be evaluated as the potential explanation of the result?

Possible Source of Bias • Is the method of subjects selection likely to have biased the result? • Is the measurement of either exposure or outcome likely to be biased? • Have the investigators considered whether confounders could account for the observed result? • In what direction would each potential bias influence the result?

Interpretation of Result • How large is the observed effect? • Is there evidence of dose response relationship? • Are the effect biologically plausible? • If the finding is negative, was there sufficient statistical power to detect the effect?

How the Result Can Be Used • Are the findings consistent with the other studies of the same question? • Can the findings be generalized to the target population in general?

Selection Bias

D+ D- E+ a b E- c d Misclassification • Exposure misclassification : non differential • Bias toward the null or dilution of effect

D+ D- E+ a b E- c d Misclassification • Exposure misclassification : differential • Bias toward/away from the null : Recall bias

D+ D- E+ a b E- c d Misclassification • Disease misclassification : non differential • Decrease power

D+ D- E+ a b E- c d Misclassification • Disease misclassification : differential • Bias toward/away from the null

Strength Consistency Specificity Temporality Biological gradient Plausibility Coherence Experimental evidence Analogy Causal Criteria

Hierarchy of Population and Inference External population External Validity (Generalizability) Issue of population difference Target population Internal validity Issue of bias Actual population Statistical inference Issue of chance Study population (Sample)

Critical Appraisal วิจารณญาณ