. 2013 Jun 1;15(11):1858–1866. doi: 10.1093/ntr/ntt068

Table 2.

Comparison of Joint (i.e., Independent) and Separate Ordinary Least Squares Regression Estimates of Per Pack Price Reductions

Cigarette price minimization strategy	Separate model (non-independent effects)^a		Joint model (independent effects)^a,b		Percent change^c
Cigarette price minimization strategy	Coefficient	95% CI	Coefficient	95% CI	Percent change^c
Carton purchase	−75***	(−78, −72)	−68***	(−71, −65)	−9%***
Out-of-state purchase	−106***	(−115, −98)	−83***	(−91, −75)	−22%***
Other purchase	−120***	(−160, −80)	−94***	(−128, −60)	−22%

Note. CI = confidence interval

^aAll models (joint and separate) were adjusted for sociodemographic characteristics, smoking characteristics, state fixed effects, survey month fixed effects, and average cigarette prices.

^bData also presented in Table 1.

^cCalculated as ((Coefficient [joint model] – coefficient [separate model]) / (coefficient [separate model])) × 100%.

***Significant at .1% level.