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katie80
Fluorite | Level 6

I am starting to think there is no way to run a random-effects Tobit in SAS. Am I wrong? Please tell me I am wrong. 

1 ACCEPTED SOLUTION

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alexchien
Pyrite | Level 9

i believed the PARMS statement provides the initial value for the model parameters, not the final estimates. PARMS statement is optional if you dont have a good initial values for any of the parameters.

 

 

PARMS Statement

 

PARMS <name_list [=numbers] [, name_list [=numbers] ... ]>
</ options>
;

The PARMS statement lists names of parameters and specifies initial values, possibly over a grid. You can specify the parameters and values directly in a list, or you can provide the name of a SAS data set that contains them by using the DATA= option.

While the PARMS statement is not required, you are encouraged to use it to provide PROC NLMIXED with accurate starting values. Parameters not listed in the PARMS statement are assigned an initial value of 1. PROC NLMIXED considers all symbols not assigned values to be parameters, so you should specify your modeling statements carefully and check the output from the "Parameters" table to make sure the proper parameters are identified.

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4 REPLIES 4
katie80
Fluorite | Level 6

I have already seen those pages and honestly they are not helpful. The code predefines the parameters that I am interested in. 

alexchien
Pyrite | Level 9

i believed the PARMS statement provides the initial value for the model parameters, not the final estimates. PARMS statement is optional if you dont have a good initial values for any of the parameters.

 

 

PARMS Statement

 

PARMS <name_list [=numbers] [, name_list [=numbers] ... ]>
</ options>
;

The PARMS statement lists names of parameters and specifies initial values, possibly over a grid. You can specify the parameters and values directly in a list, or you can provide the name of a SAS data set that contains them by using the DATA= option.

While the PARMS statement is not required, you are encouraged to use it to provide PROC NLMIXED with accurate starting values. Parameters not listed in the PARMS statement are assigned an initial value of 1. PROC NLMIXED considers all symbols not assigned values to be parameters, so you should specify your modeling statements carefully and check the output from the "Parameters" table to make sure the proper parameters are identified.

katie80
Fluorite | Level 6

By the way, if anyone else working with RETobit, I would look at the first link, the code in the second link has some errors. 

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