biprobit for Bivariate Probit: Change in parameter naming convention since v13

[John Mullahy]

I noticed today that a Mata program I developed that calls the -biprobit- procedure and that is reported in http://www.stata-journal.com/article...article=st0423 must be modified to run in Stata v15.

The basic issue is that the way the -athrho- parameter is named in -biprobit- has changed (the change may have occurred in v14, but I jumped immediately from v13 to v15). This code shows the difference

. version 13
. biprobit y1 y2 x
[results suppressed]
. matrix list e(b)

e(b)[1,5]
            y1:         y1:         y2:         y2:     athrho:
             x       _cons           x       _cons       _cons
y1  -.08699015   .05623618   .08124519  -.03078105  -.10348424

. version 15
. biprobit y1 y2 x
[results suppressed]
. matrix list e(b)

e(b)[1,5]
            y1:         y1:         y2:         y2:          /:
             x       _cons           x       _cons      athrho
y1  -.08699015   .05623618   .08124519  -.03078105  -.10348424

The smaller issue is that anyone wanting to use the method I proposed in the aforelinked Stata Journal paper should add a "version 13" to the top of the code. The larger issue is to alert anyone using -biprobit- to this change.

P.S. I may have missed a general update statement regarding parameter names in v15 (or possibly v14), and apologize if the information provided here is redundant.

[John Mullahy]

P.S. I just checked and the change must have occurred between v14 and v15, as specifying -version 14- results in the same naming convention as does -version 13-.