Table 2.

Missing data for survey questions about date of first and last sex with most recent partner among sexually active female online daters in the U.S., 2007–2012

		Date of first sex			Date of last sex
	N	n	%		n	%
Missing response for date of sex, categorical	650	3	0.5		28	4.3
Missing response for date of sex, continuous	650	20	3.1		27	4.2
Incomplete response for date of sex, continuous
Wrote year only-missing values for month and day	650	32	4.9		4	0.6
Wrote month and year-missing value for day	650	163	25.1		90	13.9
				χ2a			χ2a
				p			p
Incomplete responses (missing values for either month or day), by subgroups	650	195	30.0		94	14.5
Age (years)	650			ns			.004
18–24	179	40	22.4		17	9.5
25–29	190	63	33.2		23	12.1
30–39	160	52	32.5		25	15.6
40–65	121	40	33.1		29	24.0
Marital Status	643			ns			ns
Unmarried	456	140	30.7		70	15.4
Unmarried, living with a partner	98	26	26.5		9	9.2
Married	65	21	32.3		7	10.8
Separated	24	8	33.3		7	29.2
Lifetime Number of Sex Partners	631			ns			ns
1–4	124	31	25.0		14	11.3
5–7	126	43	34.1		18	14.3
8–12	132	41	31.1		22	16.7
13–22	122	40	32.8		20	16.4
23+	127	33	26.0		18	14.2
Thought Partner had other concurrent sex partners	629			.001			.01
No	340	80	23.5		36	10.6
Yes	172	66	38.4		35	20.4
Don’t know	117	42	35.9		19	16.2
Number of male sex partners in past 12 months	595			ns			ns
1	271	83	30.6		35	12.9
2 or more	324	96	29.6		49	15.1
Type of Sex Partner	635			ns			ns
Regular	474	148	31.2		64	13.5
Casual	161	44	27.3		28	17.4
Met Sex Partner Online	646			ns			ns
Yes	238	61	25.6		31	13.0
No	408	133	32.6		63	15.4

^aPearson’s chi-squared hypothesis test for independence between missing status (yes/no) and each subgroup of the characteristic.