Table 1. Mean square error for 5 models for the number of calls to the Quitline and NRT campaigns.

Mean model	Distribution of response variable Yj	Mean square error (MSE)
Model 1: $E(Y_j)=\alpha +{\gamma }_{7}TAR{P}_j^{Quit}+{\gamma }_{8}TAR{P}_j^{NRT}$	Gaussian	2348
Model 2: $E(Y_j)=\alpha +{\gamma }_{7}TAR{P}_j^{Quit}+{\gamma }_{8}TAR{P}_j^{NRT}$	Poisson	2348
Model 3: $E(Y_j|F_{j-1})=Y_{j-1}(\alpha +{\text{X}}_j^T\beta )+{\text{Z}}_j^T\gamma$	Conditional Poisson	915
Model 4: $E(Y_j|F_{j-1})=Y_{j-1}{\alpha }_j+{\text{Z}}_j^T\gamma$	Conditional Poisson	863
Model 5: $E(Y_j|F_{j-1})=Y_{j-1}({\alpha }_j+{\mathbf{X}}_j^T\beta )+{\mathbf{Z}}_j^T\gamma$	Conditional Poisson	820

Abbreviation: NRT, nicotine replacement therapy.