Table 2.

Study characteristics impacting findings about effect of area-level SES on substance use

	Significant effect of SES		Supports disadvantage hypothesis
	N=180 effects	OR (95% CI)	N=171 effects	OR (95% CI)
Area size
Census tract or smaller area	39.1%	0.51 (0.11, 2.28)	25.4%	0.74 (0.16, 3.37)
ZIP code or school catchment area	21.4%	0.29 (0.06, 1.40)	9.4%	0.25 (0.05, 1.30)*
Community or larger	66.7%	---	33.3%	---
Measure of SES
Composite	47.3%	1.34 (0.52, 3.48)	25.0%	1.62 (0.59, 4.48)
Single-item measure	25.6%	---	13.8%	---
Age of respondents
Adolescents	23.9%	0.37 (0.14, 0.94)**	11.2%	0.40 (0.14, 1.09)*
Adults	46.3%	---	26.6%	---
Nationality/ethnicity of sample
US white	52.2%	1.98 (0.49, 8.01)	26.1%	1.36 (0.31, 5.97)
US mixed or minority	41.7%	1.88 (0.59, 5.93)	20.8%	1.31 (0.38, 4.51)
Non-US white	22.4%	---	12.1%	---
Type of outcome
Alcohol use	35.1%	0.99 (0.35, 2.80)	18.0%	2.47 (0.44, 13.77)
Illicit drug use	30.3%	1.52 (0.54, 4.30)	19.4%	3.81 (0.70, 20.79)
Substance use	25.0%	---	5.0%	---
Level of analysis
Ecological	21.4%	1.06 (0.24, 4.68)	16.1%	3.30 (0.63, 17.24)
Individual- or multi-level	37.1%	---	17.4%	---
Study design
Longitudinal	30.8%	0.28 (0.06, 1.24)*	11.5%	0.35 (0.06, 1.98)
Cross-sectional	32.5%	---	17.9%	---
Type of analysis
Bivariate	58.8%	3.29 (1.42, 7.68)***	41.2%	4.45 (1.77, 11.21)***
Multivariate	26.0%	---	11.0%	---
Multi-level analysis
Ignored clustering in data	31.0%	0.53 (0.16, 1.73)	22.4%	1.23 (0.45, 3.65)
Appropriate analysis	32.8%	---	14.2%	---
Multivariate models: Control variablesa
Inadequate controls	22.7%	1.21 (0.34, 4.34)	7.5%	0.42 (0.15, 1.10)*
Appropriate controls	29.6%	---	14.3%	---
Multivariate models: Mediatorsa
Possible mediators included	19.4%	0.30 (0.10, 0.88)**	6.6%	0.29 (0.09, 0.90)**
No mediators included	39.6%	---	19.6%	---

^*P < .10;

^**P < .05;

^***P < .01.

^aSample sizes for analyses of effects from multivariate models only = 146 and 137.

---, reference group; CI, confidence interval; OR, odds ratio from bivariate generalised estimating equation model.