Examining differential success in recruitment using respondent driven sampling (RDS) in a multi-site study of gay, bisexual and other men who have sex with men

Table 4 Reasons for Study participation and Relationship with Recruiter Among Participants in Engage

	Vancouver (n = 753)				Toronto (n = 517)				Montreal (n = 1179)
		RDS Adjusted				RDS adjusted				RDS Adjusted
	Homophily	%	95% CI		Homophily	%	95% CI		Homophily	%	95% CI		Adjusted p-value
Reason for study participation													< 0.001
Interested in sexual health and HIV	-0.18	34.7	27.8	41.5	0.03	29.8	22.4	37.2	-0.03	36.1	30.8	41.5
Interested in gay men’s issues	0.07	17.3	12.4	22.3	0.09	11.3	6.8	15.8	0.11	16.3	12.9	19.8
My friend/partner wanted me to participate	0.03	15.7	11.1	20.3	-0.45	21.9	13.2	30.6	-0.02	9.9	7.2	12.6
Wanted to help the community	0.08	21.5	15.8	27.3	-0.13	30.4	20.9	40.0	0.06	23.7	18.9	28.5
I am mostly interested in the $50 incentive for participating	0.06	10.6	5.9	15.2	-0.43	5.7	3.3	8.1	0.14	12.7	9.3	16.0
None of the above	-1.00	0.2	0.0	0.3	-1.00	0.8	0.0	1.9	-1.00	1.3	0.5	2.1
Relationship of participant to person who gave voucher:
Partner													0.246
No	0.20	72.6	66.0	79.1	0.04	68.3	59.7	76.8	0.08	71.2	66.2	76.2
Yes	0.04	27.4	20.9	34.0	-0.19	31.7	23.2	40.3	0.03	28.8	23.8	33.8
Friend													0.224
No	-0.11	51.9	45.1	58.8	-0.09	47.5	38.2	56.8	-0.001	51.7	46.3	57.0
Yes	0.26	48.1	41.2	54.9	0.16	52.5	43.2	61.8	0.06	48.3	43.0	53.7
Acquaintance													< 0.001
No	0.13	81.0	74.9	87.2	-0.02	88.8	84.7	93.0	0.07	71.6	66.7	76.5
Yes	-0.16	19.0	12.8	25.1	0.18	11.2	7.0	15.3	0.09	28.4	23.5	33.3
Stranger													0.999
No		100.0	100.0	100.0		100.0	100.0	100.0	0.49	99.8	99.5	100.0
Yes									0.50	0.2	0.0	0.5
Other													< 0.001
No	0.33	84.6	79.4	89.8	-0.001	84.5	77.8	91.1	-0.01	96.3	94.7	98.0
Yes	0.04	15.4	10.2	20.6	-0.10	15.5	8.9	22.2	0.05	3.7	2.0	5.3

ISSN: 1471-2288