Instruments for assessing the quality of drug studies published in the medical literature.

OBJECTIVES

To develop valid and reliable instruments to assess the methodologic quality and clinical relevance of drug studies.

DESIGN

We developed an instrument to assess the methodologic quality of articles reporting clinical research and an instrument to measure nonmethodologic measures of quality, such as clinical relevance, generalizability, and adherence to ethical standards. Each instrument was pretested by seven independent, masked reviewers and modified based on interrater agreement and content validity of individual items. We determined correlational validity of the final methodologic quality instrument by comparing quality scores assigned to 10 articles by means of our instrument and a previously published one.

PARTICIPANTS

Clinical drug studies published in symposium proceedings and peer reviewed biomedical literature.

MAIN OUTCOME MEASURES

Interrater reliability of overall quality scores, measured by intraclass correlation (r) and Kendall's coefficient of concordance (W), and interrater reliability of individual items, by percentage agreement.

MAIN RESULTS

The interrater reliability of the pretest methodologic quality instrument was high (r = .89 [95% confidence interval, .73 to .96]; W = 0.64). Correlational validity of the final instrument was suggested by the high degree of concordance with another previously published one (W = 0.74). The interrater reliability of the pretest clinical relevance instrument was moderate (r = .41 [95% confidence interval, .18 to .64]; W = 0.47). Reviewers confirmed the content validity of both instruments.

CONCLUSIONS

The two instruments we developed, one measuring methodologic quality and one measuring clinical relevance of articles reporting clinical research, are reliable, valid, and applicable to a variety of research designs.