Selecting a comparison group for 5-year oral and pharyngeal cancer survivors: Two methods

Table 3 P-values for matching variables

	Sample Size^*			P-Value
Group	Survivor	Peer	Listed	Survivor vs. Peer^#	Survivor vs. Listed^$	Quality of Matching^{^^}
Variable
Sex of subject^!	100	44	96	0.47	1.00	0.99
Age (yrs)^!!	100	44	96	0.017	0.79	1.00
Education^!	99	44	96	0.75	0.41	0.018
Employment^!	100	44	96	0.18	0.25	0.28
Days of smoking in the past 30	100	44	96	0.07	0.23	0.77
Lifetime duration of smoking	60	27	53	0.32	0.011	0.18
How often do you drink alcohol? (during month)	100	44	95	0.77	0.44	0.23
How much alcohol do you drink on a typical day when you are drinking? (number of drinks)	99	42	95	0.40	0.26	0.53
How often do you drink six drinks of alcohol in one day? (during month)	100	34	95	0.51	0.42	0.25

*: sample sizes vary due to missing data.
#: Two-sided p-values for testing H_o: “the marginal distribution of survivors is the same as that of peers” vs. H_a: ”the two marginal distributions are different”. The smaller the p-value, the larger the difference between the two marginal distributions.
$: Two-sided p-values for testing H_o: ”the marginal distribution of survivors is the same as that of listed sample” vs. H_a: ”the two marginal distributions are different”. The smaller the p-value, the larger the difference between the two marginal distributions.
^^: One-sided p-values for testing H_o: ”the quality of matching between peers and survivors is the same as that between listed samples and survivors” vs. H_a: ”the quality of matching between peers and survivors is better than that between listed samples and survivors”.

ISSN: 1471-2288