. Author manuscript; available in PMC: 2017 Mar 24.

Published in final edited form as: Psychopharmacology (Berl). 2015 Sep 21;232(24):4493–4503. doi: 10.1007/s00213-015-4076-x

Table 1.

Differences between alcohol-dependent cases and controls before and after propensity-score matching based on age, gender, education, and income.

Variable	Samples	Bias (%)	Reduction in Bias (%)	Case vs. Control	Variance ratio (case/control)
Age	Unmatched	−38.5	92.7	t = 4.39^***	1.19
Age	Matched	−2.8		t = 0.23	1.04
Male (%)	Unmatched	56.9	97.5	Χ ² = 38.91^***	1.10
Male (%)	Matched	1.4		Χ ² = 0.01	1.00
Education	Unmatched	−84.5	93.0	z = 8.64^***	0.56
Education	Matched	−5.9		z = 0.38	0.92
Income	Unmatched	−105.8	88.9	z = 10.59^***	1.14
Income	Matched	−11.8		z = 1.40	1.25
Health Status	Unmatched	−27.0	17.1	z = 3.15^***	1.06
Health Status	Matched	−22.4		z = 1.89	1.08
Depression Treatment (%)	Unmatched	30.3	−42.8	Χ ² = 11.74^***	1.25
Depression Treatment (%)	Matched	43.2		Χ ² = 12.95^***	1.34

Notes:

p<.05,

^**

p<.01,

^***

p<.001.

Where Bias is positive, the mean, median, or percentage is greater for cases than for controls.