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Downs and Black Checklist (DBC)


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evaluation focus

Critical Appraisal of Research Study Methodologies.

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The Downs and Black Checklist (DBC) is an instrument that can be used to critically appraise the quality of quantitative research study methodology. This tool may be useful to healthcare providers, policy-makers, and more.


5 Sections Assessed:

    • Study quality
    • External validity
    • Study bias
    • Confounding and selection bias
    • Power of the study

Scores Available:

    • Overall Score
    • Individual Section Scores

Administration Format: checklist of 27 Y/N questions


Reliability (Downs 1998):

    • Internal Consistency:
        • Quality Index: high (0.89) for randomized and non-randomized studies
        • Subscales: adequate for three subscales, poor for one subscale (external validity).
        • Combined Internal/External Validity: high (0.72) for randomized and non-randomized
    • Test-Retest:
        • Quality Index: high (0.88)
        • Subscales: ranged from high (bias) to low (external validity).
    • Interrater:
      • Quality Index: good (0.75)
      • Subscales: ranged from good (bias) to poor (external validity)

Validity (Downs 1998):

    • Criterion Validity: quality index highly correlated (0.90) with SRTG score (RCT) and Global Score
      • RCTs and non-RCTs: 0.89
      • RCTs: 0.88
      • Non-RCTs: 0.86

Source: https://www.nccmt.ca/knowledge-repositories/search/9

supporting literature

Downs, S.H., Black, N. (1998) The Feasibility of Creating a Checklist for the Assessment of the Methodological Quality both of Randomized and Non-Randomized Studies of Health Care Interventions. Journal of Epidemiology and Community Health, 52(6), 377-384.
PDF: DBC – 1 – Downs 1998
Link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1756728/

Canadian Agency for Drugs and Technologies in Health. (2014) Point-of-Care Testing of International Normalized Ratio for Patients on Oral Anticoagulant Therapy: Systematic Review and Economic Analysis. The Agency, 3(1), 1-152.
PDF: DBC – 2 – Canadian Agency for Drugs and Tachnologies in Health 2014
Link: https://www.ncbi.nlm.nih.gov/books/NBK361419/

Korakakis, V., Whiteley, R., Tzavara, A., Malliaropoulos, N. (2022) The Effectiveness of Extracorporeal Shockwave Therapy in Common Lower Limb Conditions: A Systematic Review Including Quantification of Patient-Rated Pain Reduction. British Journal of Sports Medicine, 52(6), 1-22.
PDF: DBC – 3 – Korakakis 2022
Link: https://bjsm.bmj.com/content/52/6/387.long