Table 3.

Psychometric Properties for the Attitudes Toward Medical Statistics Scale

Property	Measure Used	STAT-Interest	STAT-Confidence
Item nonresponse	Proportion not answering question Mean (range)	0.08% (0% to 0.4%)	0.4% (0% to 1.3%)
Score distribution	Mean score (standard deviation), median and range	68 (SD=17) Median 70 Range 15 to 100	65 (SD=19) Median 65 Range 11 to 100
Test–retest repeatability	Correlation of scores at test and retest 2 wk later (n=220)	Pearson r=.60	Pearson r=.62
Internal consistency reliability	Cronbach's α (goal is 0.7 to 0.8; lower value suggests lack of coherence as a scale, and higher value suggests that items are redundant)	α=0.70	α=0.78
Content validity	Initial questionnaires revised based on feedback from experts in education, statistics, and cognitive psychology
Construct validity (interest scale only)		“Next time I have to make a decision about my health, I plan to…” (%yes)
Interest in statistics score		Ask my doctor for statistics (%)*	Track down statistics (%)*
Lowest quartile (15 to 54)		46	19
2nd quartile (55 to 69)		81	49
3rd quartile (70 to 79)		96	68
Highest quartile (80 to 100)		97	80

^*P<.001 (χ²).

r, correlation coefficient.