Critical Appraisal

Critical Appraisal Review covers various topics in epidemiology and related fields that are useful to the practicing physician in understanding and using published studies on skin disease topics. Readers may suggest future topics for this series by writing to the Editorial Office.

Some research issues are addressed by conducting experiments or surveys designed to directly gather the needed data. Some can be addressed by extracting relevant information from datasets already gathered for another purpose (i.e. "secondary data analysis"). The latter is generally much less expensive, but is fraught with difficulty. Despite the limitations, secondary analysis of large datasets can be extraordinarily useful, and sometimes is the only feasible approach. Here is a guide to help interpret reports from these studies.

Martin A. Weinstock

Large Datasets: Common Uses and Caveats

Kayvon Safavi


Background: Increasingly, large collections of pre-existing data are being used to analyze the occurrence, burden, and health care resources directed to the management of various skin diseases.

Objective: This article discusses a number of different types of large datasets along with their common uses. Various concerns about the use of this information are also discussed.

Conclusion: Although large datasets provide significant statistical power with readily available data, there are significant concerns, particularly regarding data quality and statistical analysis. Readers need to be aware of how an investigator has addressed these issues. Furthermore, the profession needs to be cognizant of very legitimate public concerns regarding confidentiality of personal information.


Antécédents: La survenue de diverses maladies de la peau, le fardeau qu'elles représentent et les ressources qu'elles requièrent en matière de soins de santé sont de plus en plus analysées à l'aide de vastes ensembles de données existantes.

Objectif: Discuter d'un certain nombre de vastes ensembles de données et de leur emploi habituel ainsi que de l'utilisation faite de cette information.

Conclusion: Bien que les vastes ensembles procurent des données toutes prêtes, leur qualité et leur analyse statistique soulèvent quelque inquiétude et le lecteur doit savoir comment l'investigateur traite toutes ces considérations. De même, les professionnels doivent être sensibles aux préoccupations légitimes du public quant à la confidentialité des renseignements personnels.

Received 5/15/98. Accepted for publication 7/24/98.

Department of Medicine, St. Luke¡s Medical Center, Milwaukee, Wisconsin

Reprint requests: Dr. Kayvon Safavi, Department of Medicine, St. Luke's Medical Center, Milwaukee, WI 53215, USA

Full text available in the print edition / Pour le texte intégral veuillez consulter la version imprimée.

JCMS 3(2) Contents