Radulescu et al listed criteria for evaluating a prevalence survey. This can help determine how much reliance can be placed on the findings of the study.


Key criteria:

(1) target population specified

(2) sampling method adequate (random sample vs whole population)

(3) sample size adequate

(4) response rate adequate

(5) information provided on non-responders

(6) disease definition valid and repeatable

(7) way to minimize observer bias


Additional criteria:

(1) inclusion criteria specified

(2) information provided on individuals in the study

(3) valid instruments used

(4) epidemiologic terms used correctly

(5) confidence intervals or standard errors calculated


Khumalo et al supplied an additional measure:

(1) percent of participants lost to followup acceptable


I would add an additional measure:

(1) exclusion criteria specified (in specifying the target population the exclusion of an ethnic group is mentioned, but not other exclusions)


Adequate Response

target population

population defined, with rationale for selection and explanation for why groups were excluded

sampling method


sample size

whole population ideal; else as large a sample as possible after subtraction of nonresponders

response rate

>= 70%


followup to characterize and determine reason for non-participation

disease definitions

valid and repeatable, either for several observers or a single observer

minimize observer bias

attempt to minimize bias (training, standardized methods, blinding, comparison of results if multiple observers, no evidence of an interest in a particular outcome)

inclusion criteria

adequately specified

information on participants

age range, gender distribution, ethnic group, etc.

instruments employed


epidemiologic terms

used correctly

confidence intervals or standard error

narrow 95% confidence interval and/or small sample error to indicate precision

percent lost to followup

< 20%

exclusion criteria

adequately specified


Scoring can be done as 0 if absent or 1 if present. For the implementation I used:


Criteria Met









total score =

= SUM(points for all 14 items)



• minimum score: 0

• maximum score: 14

• The ideal survey should have a score of 14.


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