Table 1. Demographics of random sample and responders of undergraduates at CU/BC.

	Total undergraduate population (CU and BC)		Randomly selected sample of students		Responders—study participants who completed consent		Analytic sample—responded to sexual assault questions on survey		Cramer’s Va
	n	%	n	%	n	%	n	%
Total	9616		2500		1671		1592
Gender
Female	5765	60%	1395	56%	956	58%	928	58%	0.030
Male	3851	40%	1105	44%	678	41%	634	40%
GNC	NA	NA	NA	NA	26	2%	26	2%
Year in school
Freshman	2080	22%	533	21%	411	25%	396	25%	0.051
Sophomore	2287	24%	589	24%	404	24%	387	24%
Junior	2483	26%	667	27%	435	26%	415	26%
Seniorb	2763	29%	711	28%	409	25%	391	25%
Age
18–20	5329	55%	1368	55%	911	55%	882	56%	0.041
21–23	3433	36%	879	35%	620	37%	587	37%
24–29	854	9%	253	10%	130	8%	120	8%
Race/ethnicity
White Non-    Hispanic	4159	43%	986	39%	708	44%	678	43%	0.086
Asian Non-    Hispanic	2583	27%	637	25%	384	24%	359	23%
Black Non-    Hispanic	1046	11%	274	11%	137	9%	132	8%
Hispanic	1104	11%	281	11%	246	14%	239	15%
Other	724	8%	322	13%	154	10%	151	10%
US born
Yes	7925	82%	2053	82%	1251	76%	1203	76%	0.074
No	1691	18%	447	18%	394	24%	373	24%
Pell Grant
Yes	1694	18%	454	18%	362	23%	352	23%	0.057
No	7922	82%	2046	82%	1225	77%	1190	77%

^aCramer’s V is a measure of effect size for the difference between the demographic distributions in the responders (n = 1671) vs the full sample (n = 2500). Cohen (1988) recommends that when Cramer’s V <0.10 this indicates small effects suggesting no practical difference between samples.

^b Senior responders included (n = 9) students who self-reported their year in school as fifth or more (undergrad only).