Table 6.

Associations of Census Tract–Level Poverty and Racial/Ethnic Composition With Numbers of Convenience Stores per Tract in 4 Metropolitan Statistical Areas, 2006–2012^a

Parameter	MSAb
	Birmingham, Alabama		Chicago, Illinois		Minneapolis, Minnesota		San Francisco, California
	PM	95% CrI	PM	95% CrI	PM	95% CrI	PM	95% CrI
Intercept	0.46	0.33, 0.57	−3.98	−4.09, −3.77	−4.67	−4.87, −4.47	0.30	0.08, 0.42
Logit povertyc	0.13	0.11, 0.16			0.23	0.22, 0.25	0.41	0.34, 0.46
Poverty levelc
High vs. low			0.32	0.29, 0.35
Medium vs. low			0.37	0.32, 0.44
Racial/ethnic compositiond
Predominantly black vs. white	0.46	0.36, 0.58	0.24	0.13, 0.35
Other vs. white	0.97	0.86, 1.09	0.16	0.13, 0.18	−0.37	−0.43, −0.30	−0.47	−0.60, −0.22
Poverty × racial/ethnic composition
Poverty × predominantly black vs. white	0.15	0.09, 0.21
Poverty × other vs. white	0.36	0.31, 0.41			−0.22	−0.25, −0.18	−0.22	−0.27, −0.15
Poverty level × racial/ethnic composition
High poverty × predominantly black			−0.28	−0.41, −0.16
Medium poverty × predominantly black			−0.31	−0.43, −0.18
High poverty × other			−0.30	−0.37, −0.24
Medium poverty × other			−0.13	−0.17, −0.09
Areae	0.09	0.06, 0.12	0.63	0.57, 0.70	0.23	0.21, 0.25	0.09	0.07, 0.12
Populatione	0.13	0.11, 0.15	0.48	0.45, 0.49	0.67	0.64, 0.69	0.15	0.14, 0.16
Area × population	0.0005	−0.005, 0.005	−0.05	−0.06, −0.04	0.03	0.02, 0.05	−0.01	−0.02, −0.008
Time (linear)	0.007	0.002, 0.01	0.02	0.01, 0.02	0.005	−0.002, 0.01	0.03	0.02, 0.03
Time (quadratic)	−0.0002	−0.0004, −0.00002	−0.0006	−0.0008, −0.0005	−0.0002	−0.0004, −0.00004	−0.0008	−0.001, −0.0006

Abbreviations: CrI, credible interval; MSA, Metropolitan Statistical Area; PM, posterior mean.

^aResults were derived from a spatial-temporal multivariable Poisson regression model accounting for region-wide heterogeneity in the 4 MSAs.

^bNumbers of census tracts (2010 census tract boundaries) falling within the MSAs: Birmingham, 264; Chicago, 2,210; Minneapolis, 772; San Francisco, 975.

except Chicago, where tertiles of the poverty variable (representing low, medium, and high poverty levels)

^cThe poverty variable was continuous (percentage of the population living below the federal poverty level) for Birmingham, Minneapolis, and San Francisco and categorical (tertile of census-tract poverty level) for Chicago.

^dReference group: white. Predominantly white or predominantly black tracts were defined as tracts with ≥70% of the tract population of a specific race/ethnicity. All other racial/ethnic categories, such as predominantly Hispanic, predominantly Asian, or racially mixed, were lumped together in the “other” category, given the small sample sizes available for analysis.

^eLog-transformed area was used for all 4 MSAs. A population/1,000 transformation was used for the Birmingham and San Francisco MSAs, while a log-transformed population variable was used for the Chicago and Minneapolis MSAs.