help bitobit-------------------------------------------------------------------------------

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

bitobitfits a two equation seemingly-unrelated model of they1variable on thex1variables and they2variable on thex2variables, where the censoring status is determined by thecensor1andcensor2variables.

Options

estimateAny 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.

y1designates the dependent variable in the first equation.

y2designates the dependent variable in the second equation.

x1designates the independent variables in the first equation.

x2designates the independent variables in the second equation.

censor1designates 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).

censor2designates 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.

ExamplesFixed 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_priceinterest_rate GDP) y2(washing_machines) x2(interest_rate GDPclothes_price dry_cleaning_price) censor1(fridge_censor)censor2(wash_censor)Variable censoring threshhold

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

AuthorDaniel Lawson, Drew University, dlawson@drew.edu

Version