TABLE 4.

One approach to assessing methodological quality and applicability of studies

Methodological quality

A. Least bias; results are valid

B. Susceptible to some bias, but not sufficient to invalidate the results

C. Significant bias that may invalidate the results

Applicability

I. Sample is representative of the target population. It should be sufficiently large to cover both sexes, a wide age range, and other important features of the target population (e.g. diet).

II. Sample is representative of a relevant sub-group of the target population, but not the entire population.

III. Sample is representative of a narrow subgroup of subjects only, and is of limited applicability to other subgroups.