Table 3.

Oral contraceptive knowledge scores among the text message intervention and routine care control groups, by knowledge dimension and question format

OC knowledge scores, by dimension and question format (# questions) [# text messages]	Baseline scores			Six-month scores			Percentage point change in scores
	Text group	Routine care	P	Text group	Routine care	P	Text group	Routine care	p
Total score (41) [47]	22.8	22.7	0.75	25.5	23.7	<0.001	7	3	<0.001
Mechanism of action (4) [4]	2.6	2.5	0.60	3.2	3.0	0.004	15	11	0.07
Effectiveness (2) [6]	1.7	1.7	0.45	1.9	1.8	<0.001	10	−6	0.05
Use (9) [17]	7.2	7.3	0.94	7.2	7.3	0.28	<1	<1	0.41
Side effects (4) [5]	2.3	2.3	0.71	3.0	2.9	0.03	18	15	0.21
Risks (9) [13]	3.3	3.1	0.27	3.4	3.4	0.87	1	3	0.34
Benefits (13) [14]	5.2	5.4	0.42	6.9	5.5	<0.001	13	9	<0.001
Question format
True-false (10)	7.7	7.6	0.23	8.7	8.1	<0.001	10	6	0.002
Alternate choice (16)	10.1	10.1	0.37	10.1	10.1	0.86	<1	<1	0.53
Multiple choice (15)	5.0	5.2	0.27	6.7	5.5	<0.001	12	2	<0.001

OC = oral contraceptives. Results are mean baseline and six-month scores (points) and percentage point change in knowledge scores overall, by OC knowledge dimension and by question format for the intervention and control groups. P-values from Student’s t-test.