Hi All,
I need help in understanding why some trajectories are missing in _traj_Group?
I am using Andrew P. Wheeler's plugin to run grouped based trajectoy models in Stata. I have 19 years of follow-up and I am using the following syntax and followed is the output of the syntax
traj if group==1, var( exposure_*) indep(t_*) model(zip) order(2 2 2 2 )
Here is an outpt
==== traj stata plugin ==== Jones BL Nagin DS, build: Jan 8 2018
60998 observations read.
51588 excluded by if condition.
9410 observations used in trajectory model.
Maximum Likelihood Estimates
Model: Zero Inflated Poisson (ZIP)
Standard T for H0:
Group Parameter Estimate Error Parameter=0 Prob > |T|
1 Intercept -0.10053 0.02925 -3.437 0.0006
Linear 0.05324 0.00808 6.585 0.0000
Quadratic 0.00140 0.00041 3.404 0.0007
2 Intercept 0.04437 0.02330 1.904 0.0569
Linear 0.00554 0.00573 0.966 0.3341
Quadratic -0.00010 0.00029 -0.343 0.7316
3 Intercept 0.04439 0.00954 4.654 0.0000
Linear 0.00553 0.00228 2.430 0.0151
Quadratic -0.00010 0.00011 -0.878 0.3799
4 Intercept -0.00685 0.02381 -0.288 0.7735
Linear 0.20418 0.00532 38.369 0.0000
Quadratic -0.00746 0.00028 -26.968 0.0000
Group membership
1 (%) 8.65836 0.44359 19.519 0.0000
2 (%) 12.49223 383.21558 0.033 0.9740
3 (%) 69.66792 383.21579 0.182 0.8557
4 (%) 9.18149 0.39125 23.467 0.0000
BIC=-178850.40 (N=155079) BIC=-178829.39 (N=9410) AIC=-178775.77 L=-178760.77
When I tab _traj_Group, it does not return values for trajectory group 2
_traj_Group | Freq. Percent Cum.
------------+-----------------------------------
1 | 708 7.52 7.52
3 | 7,855 83.48 91.00
4 | 847 9.00 100.00
------------+-----------------------------------
Total | 9,410 100.00
Can someone tell what can possibly be wrong here?
I need help in understanding why some trajectories are missing in _traj_Group?
I am using Andrew P. Wheeler's plugin to run grouped based trajectoy models in Stata. I have 19 years of follow-up and I am using the following syntax and followed is the output of the syntax
traj if group==1, var( exposure_*) indep(t_*) model(zip) order(2 2 2 2 )
Here is an outpt
==== traj stata plugin ==== Jones BL Nagin DS, build: Jan 8 2018
60998 observations read.
51588 excluded by if condition.
9410 observations used in trajectory model.
Maximum Likelihood Estimates
Model: Zero Inflated Poisson (ZIP)
Standard T for H0:
Group Parameter Estimate Error Parameter=0 Prob > |T|
1 Intercept -0.10053 0.02925 -3.437 0.0006
Linear 0.05324 0.00808 6.585 0.0000
Quadratic 0.00140 0.00041 3.404 0.0007
2 Intercept 0.04437 0.02330 1.904 0.0569
Linear 0.00554 0.00573 0.966 0.3341
Quadratic -0.00010 0.00029 -0.343 0.7316
3 Intercept 0.04439 0.00954 4.654 0.0000
Linear 0.00553 0.00228 2.430 0.0151
Quadratic -0.00010 0.00011 -0.878 0.3799
4 Intercept -0.00685 0.02381 -0.288 0.7735
Linear 0.20418 0.00532 38.369 0.0000
Quadratic -0.00746 0.00028 -26.968 0.0000
Group membership
1 (%) 8.65836 0.44359 19.519 0.0000
2 (%) 12.49223 383.21558 0.033 0.9740
3 (%) 69.66792 383.21579 0.182 0.8557
4 (%) 9.18149 0.39125 23.467 0.0000
BIC=-178850.40 (N=155079) BIC=-178829.39 (N=9410) AIC=-178775.77 L=-178760.77
When I tab _traj_Group, it does not return values for trajectory group 2
_traj_Group | Freq. Percent Cum.
------------+-----------------------------------
1 | 708 7.52 7.52
3 | 7,855 83.48 91.00
4 | 847 9.00 100.00
------------+-----------------------------------
Total | 9,410 100.00
Can someone tell what can possibly be wrong here?
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