Can patients interpret health information? An assessment of the medical data interpretation test.
OBJECTIVE
To establish the reliability/validity of an 18-item test of patients' medical data interpretation skills.


METHODS
Survey with retest after 2 weeks. Subjects. 178 people recruited from advertisements in local newspapers, an outpatient clinic, and a hospital open house.


RESULTS
The percentage of correct answers to individual items ranged from 20% to 87%, and medical data interpretation test scores (on a 0- 100 scale) were normally distributed (median 61.1, mean 61.0, range 6-94). Reliability was good (test-retest correlation=0.67, Cronbach's alpha=0.71). Construct validity was supported in several ways. Higher scores were found among people with highest versus lowest numeracy (71 v. 36, P<0.001), highest quantitative literacy (65 v. 28, P<0.001), and highest education (69 v. 42, P=0.004). Scores for 15 physician experts also completing the survey were significantly higher than participants with other postgraduate degrees (mean score 89 v. 69, P<0.001).


CONCLUSIONS
The medical data interpretation test is a reliable and valid measure of the ability to interpret medical statistics.
Schwartz
Lisa M
LM
VA Outcomes Group, White River Junction, VT 05009, USA. Lisa.Schwartz@Dartmouth.edu
Woloshin
Steven
S
Welch
H Gilbert
HG
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003627:Data Interpretation, Statistical; D003657:Decision Making; D004521:Educational Measurement; D004522:Educational Status; D005260:Female; D019538:Health Care Surveys; D007722:Health Knowledge, Attitudes, Practice; D006801:Humans; D007255:Information Services / Q000706:statistics & numerical data; D008297:Male; D008875:Middle Aged; D009513:New Hampshire; D010353:Patient Education as Topic / Q000706:statistics & numerical data*; D011594:Psychometrics / Q000295:instrumentation*; D018570:Risk Assessment / Q000706:statistics & numerical data*; D012307:Risk Factors; D011795:Surveys and Questionnaires