Table 3.

GEE Regression Coefficients Representing Monthly Change in Drug Use by SSA Recipient Groups Compared with Nonrecipients

Comparison	Clinician-Rated Drug Use Severity	$ Spent on Drugs in Last 30 Days	Drug Problem Days in Last 30 Days	Days Crack in Last 30 Days
Group × Time
SSA 3 months versus no SSA	−0.03 (0.03)	−2.5 (2.4)	0.1 (0.1)	−0.08 (0.05)
SSA 12 months versus no SSA	−0.02 (0.02)	7.9 (7.0)	0.1 (0.1)	− 0.07 (0.05)
SSA throughout versus no SSA	0.07 (0.02)***	5.0 (2.7)	0.2 (0.10)	0.10 (0.06)
Group × time squared
SSA 3 months versus no SSA	0.003 (0.002)	0.2 (0.2)	−0.009 (0.01)	0.005 (0.005)
SSA 12 months versus no SSA	0.001 (0.002)	−0.7 (0.6)	−0.01 (0.01)	0.005 (0.004)
SSA throughout versus no SSA	−0.006 (0.002)***	−0.4 (0.2)	−0.01 (0.008)	−0.009 (0.005)

Values represent parameter estimates (SE) after allowance for covariates.

^*Denotes rate of change different from No SSA group at p≤.01.

^**Differs at p<.005.

^***Differs at p<.001.

SSA, Social Security Administration; GEE, generalized estimating equations.