Description Usage Arguments Details Value References See Also Examples

Estimates a GMM probit model for a 0-1 dependent variable
and an underlying latent variable of the form *Y^* = ρ WY^* + X β +u*

1 2 3 |

`form` |
Model formula |

`inst` |
List of instruments |

`winst` |
List of instruments to be pre-multiplied by |

`wmat` |
Directly enter |

`shpfile` |
Shape file to be used for creating the |

`startb` |
Vector of starting values for |

`startrho` |
Vector of starting values for |

`blockid` |
A variable identifying groups used to specify a block diagonal structure for the |

`cvcrit` |
Convergence criterion. Default: |

`data ` |
A data frame containing the data. Default: use data in the current working directory. |

`silent ` |
If |

The underlying latent variable for the model is *Y* = ρ WY* + X β + u*
or *Y* = (I - ρ W)^{-1}(X β + u)*.
The covariance matrix is *Euu' = σ^2 ((I - ρ W)(I - ρ W)')^{-1}*, with *σ^2* normalized to unity.
Typical specifications imply heteroskedasticity, i.e., the diagonal elements of *Euu'*, denoted by *σ_i^2*, vary across observations.
Heteroskedasticity makes standard probit estimates inconsistent. Letting *X_i^* = X_i/ σ_i* and *H = (I - ρ W)^{-1} X^**,
the probit probabilities implied by the latent variable are *p = Φ(H β)* and the generalized error term is *e = (y - p)φ(H β)/(p(1-p)) *,
where *y = 1* if *Y^* >0* and *y = 0* otherwise.

The GMM estimator chooses *β* and *ρ* to minimize *e'Z(Z'Z)^{-1}Z'e*,
where *Z* is a matrix of instruments specified using the *inst* and *winst* options.
Unless specified otherwise using the *startb* and *startrho* options, initial estimates are obtained using *spprobit*,
which implements the simple (and fast) linearized version of the GMM probit model proposed by Klier and McMillen (2008).
Convergence is defined by *abs(change) < cvcrit*, where *change* is the gradient vector implied by applying a standard Gauss-Newton algorithm to the objective function.
The covariance matrix (equation 3 in Klier-McMillen, 2008) is estimated using the *car* package.

Estimation can be very slow because each iteration requires the inversion of an *nxn* matrix.
To speed up the estimation process and to reduce memory requirements, it may be desirable to impose a block diagonal structure on *W*.
For example, it may be reasonable to impose that each state or region has its own error structure, with no correlation of errors across regions.
The *blockid* option specifies a block diagonal structure such as *blockid=region*.
The option leads the program to re-calculate the *W* matrix, imposing the block diagonal structure and re-normalizing the matrix to again have each row sum to one.
If there are *G* groups, estimation requires *G* sub-matrices to be inverted rather than one *nxn* matrix,
which greatly reduces memory requirements and significantly reduces the time required in estimation.

*gmmprobit* provides flexibility in specifying the list of instruments.
By default, the instrument list includes *X* and *WX*, where *X* is the original explanatory variable list and *W* is the spatial weight matrix.
It is also possible to directly specify the full instrument list or to include only a subset of the *X* variables in the list that is to be pre-multiplied by *W*.

Let *list1* and *list2* be user-provided lists of the form *list=~z1+z2*.
The combinations of defaults (*NULL*) and lists for *inst* alter the final list of instruments as follows:

*inst = NULL*, *winst = NULL*: *Z = (X, WX)*

*inst = list1*, *winst = NULL*: *Z = list1*

*inst = NULL*, *winst = list2*: *Z = (X, W*list2)*

*inst = list1*, *winst = list2*: *Z = (list1, W*list2)*

Note that when *inst=list1* and *winst=NULL* it is up to the user to specify at least one variable in *list1* that is not also included in *X*.

`coef ` |
Coefficient estimates |

`se ` |
Standard error estimates |

Klier, Thomas and Daniel P. McMillen, "Clustering of Auto Supplier Plants in the United
States: Generalized Method of Moments Spatial probit for Large Samples," *Journal of
Business and Economic Statistics* 26 (2008), 460-471.

Pinkse, J. and M. E. Slade, "Contracting in Space: An Application of Spatial Statistics to
Discrete-Choice Models," *Journal of Econometrics* 85 (1998), 125-154.

cparlogit

cparprobit

cparmlogit

gmmlogit

splogit

spprobit

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 | ```
set.seed(9947)
cmap <- readShapePoly(system.file("maps/CookCensusTracts.shp",
package="McSpatial"))
cmap <- cmap[cmap$CHICAGO==1&cmap$CAREA!="O'Hare",]
lmat <- coordinates(cmap)
dnorth <- geodistance(lmat[,1],lmat[,2], -87.627800,
41.881998, dcoor=TRUE)$dnorth
cmap <- cmap[dnorth>0,]
wmat <- makew(cmap)$wmat
n = nrow(wmat)
rho = .4
x <- runif(n,0,10)
ystar <- as.numeric(solve(diag(n) - rho*wmat)%*%(x + rnorm(n,0,2)))
y <- ystar>quantile(ystar,.4)
fit <- gmmprobit(y~x, wmat=wmat)
``` |

McSpatial documentation built on May 30, 2017, 12:34 a.m.

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