Table 1

Preferences for STI testing characteristics, expressed as ORs

Attributes and levels	Unadjusted ORs	p Value	Adjusted ORs^*	p Value
Time to appointment
Drop in same day and wait	1.36 (1.28 to 1.45)	<0.001	1.36 (1.27 to 1.45)	<0.001
Within 24 h	1.27 (1.21 to 1.35)	<0.001	1.27 (1.20 to 1.35)	<0.001
Within 48 h	1.0	–	1.0	–
After 48 h but at individuals convenience	1.06 (1.00 to 1.11)	0.027	1.04 (0.99 to 1.10)	0.11
Results waiting time
Same day	1.61 (1.52 to 1.72)	<0.001	1.65 (1.55 to 1.77)	<0.001
3 days	1.24 (1.18 to 1.31)	<0.001	1.26 (1.19 to 1.33)	<0.001
7 days	1.0	–	1.0	–
21 days	0.63 (0.59 to 0.66)	<0.001	0.62 (0.58 to 0.65)	<0.001
Comprehensive of results
Positive results only	1.0	–	1.0	–
Positive and negative results	1.25 (1.21 to 1.28)	<0.001	1.24 (1.21 to 1.29)	<0.001
Staff
Staff without specialist STI knowledge	1.0	–	1.0	–
Staff with specialist STI knowledge	2.55 (2.47 to 2.63)	<0.001	2.64 (2.56 to 2.73)	<0.001
Comprehensiveness of testing
Tests for most STIs^†	1.0	–	1.0	–
Tests for all STIs	2.19 (2.12 to 2.25)	<0.001	2.23 (2.16 to 2.31)	<0.001
Results reporting method
Phone up test centre	1.0	–	1.0	–
Post to home address	0.82 (0.78 to 0.86)	<0.001	0.81 (0.77 to 0.86)	<0.001
By email	0.94 (0.88 to 1.00)	0.036	0.94 (0.88 to 1.00)	0.055
Text or call to mobile phone by centre	1.02 (0.97 to 1.08)	0.48	1.00 (0.95 to 1.06)	0.97

Figures in brackets represent 95% CIs. For the main unadjusted model: constant, OR 0.70 (0.68 to 0.72), log-likelihood =−14 047, no. of observations = 26 538, no. of groups (participants) =3355, average no. of DCE questions completed per participant =99%, ρ=3.90×10⁷, p=0.49, McFadden's adjusted r²=0.22, the model predicts 74% of answers correctly.
↵* Adjusted for age, sex, CASH, MSM, no. of previous tests, symptoms of STIs, educations and employment status.
↵† Excluded tests were syphilis, herpes and HIV.
DCE, discrete choice experiment; MSM, men who have sex with men; STI, sexually transmitted infection.