```help bitobit
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Title

[R] bitobit --  Bivariate Tobit regression

Syntax

bitobit estimate [if] [in] , y1(depvar1) y2(depvar2) x1(varlist)
x2(varlist) censor1(varname) censor1(varname) [level(#)]

Description

bitobit fits a two equation seemingly-unrelated model of the y1 variable
on the x1 variables and the y2 variable on the x2 variables, where the
censoring status is determined by the censor1 and censor2 variables.

Options

estimate Any arbitrary string of letters or numbers could be substituted
for the word "estimate"; an argument before the comma is required so the
syntax command recognizes this as an estimation command and not a replay
command.

y1 designates the dependent variable in the first equation.

y2 designates the dependent variable in the second equation.

x1 designates the independent variables in the first equation.

x2 designates the independent variables in the second equation.

censor1 designates the variable that indicates the censoring status of
the first equation.  For observations where this variable takes on a
value of zero, the actual value is equal to the observed value of y1 (no
censoring).  For observations where this variable takes on a value of
one, the actual value is above the observed value of y1 (left censoring).
For observations where this variable takes on a value of negative one,
the actual value is less than the observed value of y1 (right censoring).

censor2 designates the variable that indicates the censoring status of
the second equation.  For observations where this variable takes on a
value of zero, the actual value is equal to the observed value of y2 (no
censoring).  For observations where this variable takes on a value of
one, the actual value is above the observed value of y2 (left censoring).
For observations where this variable takes on a value of negative one,
the actual value is less than the observed value of y2 (right censoring).

The behavior of this routine is undefined if censor1 or censor2 contain
values other than -1, 0, or 1.

Examples

Fixed censoring threshhold

. generate fridge_censor = 0

. replace fridge_censor = -1 if refrigerators == 0

. generate wash_censor = 0

. replace wash_censor = -1 if washing_machines == 0

. bitobit estimate, y1(refrigerators) x1(temperature food_price
interest_rate GDP) y2(washing_machines) x2(interest_rate GDP
clothes_price dry_cleaning_price) censor1(fridge_censor)
censor2(wash_censor)

Variable censoring threshhold

. bitobit estimate, y1(age_entering_league) x1(height weight
family_income) y2(age_leaving_league) x2(height weight family_income)
censor1(hasnt_joined_league_to_date)
censor2(hasnt_left_league_to_date)

Author

Daniel Lawson, Drew University, dlawson@drew.edu

Version

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