Patients and Medical Statistics. Interest, Confidence, and Ability

Background: People are increasingly presented with medical statistics. There are no existing measures to assess their level of interest or confidence in using medical statistics.

Objective: To develop 2 new measures, the STAT-interest and STAT-confidence scales, and assess their reliability and validity.

Design: Survey with retest after approximately 2 weeks.

Subjects: Two hundred and twenty-four people were recruited from advertisements in local newspapers, an outpatient clinic waiting area, and a hospital open house.

Measures: We developed and revised 5 items on interest in medical statistics and 3 on confidence understanding statistics.

Results: Study participants were mostly college graduates (52%); 25% had a high school education or less. The mean age was 53 (range 20 to 84) years. Most paid attention to medical statistics (6% paid no attention). The mean (SD) STAT-interest score was 68 (17) and ranged from 15 to 100. Confidence in using statistics was also high: the mean (SD) STAT-confidence score was 65 (19) and ranged from 11 to 100. STAT-interest and STAT-confidence scores were moderately correlated (r=.36, P<.001). Both scales demonstrated good test-retest repeatability (r=.60, .62, respectively), internal consistency reliability (Cronbach's alpha=0.70 and 0.78), and usability (individual item nonresponse ranged from 0% to 1.3%). Scale scores correlated only weakly with scores on a medical data interpretation test (r=.15 and .26, respectively).

Conclusion: The STAT-interest and STAT-confidence scales are usable and reliable. Interest and confidence were only weakly related to the ability to actually use data.