R中的两级最小二乘法

Man*_*ino 6 regression r least-squares stata

我想在R中运行两阶段概率最小二乘回归.有谁知道如何做到这一点?那里有包裹吗?我知道使用Stata可以做到这一点,所以我想可以用R做它.

eyj*_*yjo 8

当你说'两阶段 - 概率最小二乘'时,你可能想要更具体.既然你提到了实现这个的Stata程序,我猜你正在谈论CDSIMEQ包,它实现了Heckit模型的Amemiya(1978)程序(又名广义Tobit,又名Tobit II型模型等).正如格兰特所说,systemfit将为你做一个托比特,但不是两个方程式.MicEcon软件包确实有一个Heckit(但是软件包分裂了很多次,我不知道它现在在哪里).

如果你想要CDSIMEQ的功能,可以很容易地在R中实现.我写了一个复制CDSIMEQ的函数:

tspls <- function(formula1, formula2, data) {
    # The Continous model
    mf1 <- model.frame(formula1, data)
    y1 <- model.response(mf1)
    x1 <- model.matrix(attr(mf1, "terms"), mf1)

    # The dicontionous model
    mf2 <- model.frame(formula2, data)
    y2 <- model.response(mf2)
    x2 <- model.matrix(attr(mf2, "terms"), mf2)

    # The matrix of all the exogenous variables
    X <- cbind(x1, x2)
    X <- X[, unique(colnames(X))]

    J1 <- matrix(0, nrow = ncol(X), ncol = ncol(x1))
    J2 <- matrix(0, nrow = ncol(X), ncol = ncol(x2))
    for (i in 1:ncol(x1)) J1[match(colnames(x1)[i], colnames(X)), i] <- 1
    for (i in 1:ncol(x2)) J2[match(colnames(x2)[i], colnames(X)), i] <- 1

    # Step 1:
    cat("\n\tNOW THE FIRST STAGE REGRESSION")
    m1 <- lm(y1 ~ X - 1)
    m2 <- glm(y2 ~ X - 1, family = binomial(link = "probit"))
    print(summary(m1))
    print(summary(m2))

    yhat1 <- m1$fitted.values
    yhat2 <- X %*% coef(m2)

    PI1 <- m1$coefficients
    PI2 <- m2$coefficients
    V0 <- vcov(m2)
    sigma1sq <- sum(m1$residuals ^ 2) / m1$df.residual
    sigma12 <- 1 / length(y2) * sum(y2 * m1$residuals / dnorm(yhat2))

    # Step 2:
    cat("\n\tNOW THE SECOND STAGE REGRESSION WITH INSTRUMENTS")

    m1 <- lm(y1 ~ yhat2 + x1 - 1)
    m2 <- glm(y2 ~ yhat1 + x2 - 1, family = binomial(link = "probit"))
    sm1 <- summary(m1)
    sm2 <- summary(m2)
    print(sm1)
    print(sm2)

    # Step  3:
    cat("\tNOW THE SECOND STAGE REGRESSION WITH CORRECTED STANDARD ERRORS\n\n")
    gamma1 <- m1$coefficients[1]
    gamma2 <- m2$coefficients[1]

    cc <- sigma1sq - 2 * gamma1 * sigma12
    dd <- gamma2 ^ 2 * sigma1sq - 2 * gamma2 * sigma12
    H <- cbind(PI2, J1)
    G <- cbind(PI1, J2)

    XX <- crossprod(X)                          # X'X
    HXXH <- solve(t(H) %*% XX %*% H)            # (H'X'XH)^(-1)
    HXXVXXH <- t(H) %*% XX %*% V0 %*% XX %*% H  # H'X'V0X'XH
    Valpha1 <- cc * HXXH + gamma1 ^ 2 * HXXH %*% HXXVXXH %*% HXXH

    GV <- t(G) %*% solve(V0)    # G'V0^(-1)
    GVG <- solve(GV %*% G)      # (G'V0^(-1)G)^(-1)
    Valpha2 <- GVG + dd * GVG %*% GV %*% solve(XX) %*% solve(V0) %*% G %*% GVG

    ans1 <- coef(sm1)
    ans2 <- coef(sm2)

    ans1[,2] <- sqrt(diag(Valpha1))
    ans2[,2] <- sqrt(diag(Valpha2))
    ans1[,3] <- ans1[,1] / ans1[,2]
    ans2[,3] <- ans2[,1] / ans2[,2]
    ans1[,4] <- 2 * pt(abs(ans1[,3]), m1$df.residual, lower.tail = FALSE)
    ans2[,4] <- 2 * pnorm(abs(ans2[,3]), lower.tail = FALSE)

    cat("Continuous:\n")
    print(ans1)
    cat("Dichotomous:\n")
    print(ans2)
}
Run Code Online (Sandbox Code Playgroud)

为了比较,我们可以在他们关于包文章中复制CDSIMEQ作者的样本.

> library(foreign)
> cdsimeq <- read.dta("http://www.stata-journal.com/software/sj3-2/st0038/cdsimeq.dta")
> tspls(continuous ~ exog3 + exog2 + exog1 + exog4,
+     dichotomous ~ exog1 + exog2 + exog5 + exog6 + exog7,
+     data = cdsimeq)

        NOW THE FIRST STAGE REGRESSION
Call:
lm(formula = y1 ~ X - 1)

Residuals:
      Min        1Q    Median        3Q       Max 
-1.885921 -0.438579 -0.006262  0.432156  2.133738 

Coefficients:
              Estimate Std. Error t value Pr(>|t|)    
X(Intercept)  0.010752   0.020620   0.521 0.602187    
Xexog3        0.158469   0.021862   7.249 8.46e-13 ***
Xexog2       -0.009669   0.021666  -0.446 0.655488    
Xexog1        0.159955   0.021260   7.524 1.19e-13 ***
Xexog4        0.316575   0.022456  14.097  < 2e-16 ***
Xexog5        0.497207   0.021356  23.282  < 2e-16 ***
Xexog6       -0.078017   0.021755  -3.586 0.000352 ***
Xexog7        0.161177   0.022103   7.292 6.23e-13 ***
---
Signif. codes:  0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1 

Residual standard error: 0.6488 on 992 degrees of freedom
Multiple R-squared: 0.5972,     Adjusted R-squared: 0.594 
F-statistic: 183.9 on 8 and 992 DF,  p-value: < 2.2e-16 


Call:
glm(formula = y2 ~ X - 1, family = binomial(link = "probit"))

Deviance Residuals: 
     Min        1Q    Median        3Q       Max  
-2.49531  -0.59244   0.01983   0.59708   2.41810  

Coefficients:
             Estimate Std. Error z value Pr(>|z|)    
X(Intercept)  0.08352    0.05280   1.582 0.113692    
Xexog3        0.21345    0.05678   3.759 0.000170 ***
Xexog2        0.21131    0.05471   3.862 0.000112 ***
Xexog1        0.45591    0.06023   7.570 3.75e-14 ***
Xexog4        0.39031    0.06173   6.322 2.57e-10 ***
Xexog5        0.75955    0.06427  11.818  < 2e-16 ***
Xexog6        0.85461    0.06831  12.510  < 2e-16 ***
Xexog7       -0.16691    0.05653  -2.953 0.003152 ** 
---
Signif. codes:  0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1 

(Dispersion parameter for binomial family taken to be 1)

    Null deviance: 1386.29  on 1000  degrees of freedom
Residual deviance:  754.14  on  992  degrees of freedom
AIC: 770.14

Number of Fisher Scoring iterations: 6


        NOW THE SECOND STAGE REGRESSION WITH INSTRUMENTS
Call:
lm(formula = y1 ~ yhat2 + x1 - 1)

Residuals:
     Min       1Q   Median       3Q      Max 
-2.32152 -0.53160  0.04886  0.53502  2.44818 

Coefficients:
              Estimate Std. Error t value Pr(>|t|)    
yhat2         0.257592   0.021451  12.009   <2e-16 ***
x1(Intercept) 0.012185   0.024809   0.491    0.623    
x1exog3       0.042520   0.026735   1.590    0.112    
x1exog2       0.011854   0.026723   0.444    0.657    
x1exog1       0.007773   0.028217   0.275    0.783    
x1exog4       0.318636   0.028311  11.255   <2e-16 ***
---
Signif. codes:  0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1 

Residual standard error: 0.7803 on 994 degrees of freedom
Multiple R-squared: 0.4163,     Adjusted R-squared: 0.4128 
F-statistic: 118.2 on 6 and 994 DF,  p-value: < 2.2e-16 


Call:
glm(formula = y2 ~ yhat1 + x2 - 1, family = binomial(link = "probit"))

Deviance Residuals: 
     Min        1Q    Median        3Q       Max  
-2.49610  -0.58595   0.01969   0.59857   2.41281  

Coefficients:
              Estimate Std. Error z value Pr(>|z|)    
yhat1          1.26287    0.16061   7.863 3.75e-15 ***
x2(Intercept)  0.07080    0.05276   1.342 0.179654    
x2exog1        0.25093    0.06466   3.880 0.000104 ***
x2exog2        0.22604    0.05389   4.194 2.74e-05 ***
x2exog5        0.12912    0.09510   1.358 0.174544    
x2exog6        0.95609    0.07172  13.331  < 2e-16 ***
x2exog7       -0.37128    0.06759  -5.493 3.94e-08 ***
---
Signif. codes:  0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1 

(Dispersion parameter for binomial family taken to be 1)

    Null deviance: 1386.29  on 1000  degrees of freedom
Residual deviance:  754.21  on  993  degrees of freedom
AIC: 768.21

Number of Fisher Scoring iterations: 6

        NOW THE SECOND STAGE REGRESSION WITH CORRECTED STANDARD ERRORS

Continuous:
                Estimate Std. Error    t value   Pr(>|t|)
yhat2         0.25759209  0.1043073 2.46955009 0.01369540
x1(Intercept) 0.01218500  0.1198713 0.10165068 0.91905445
x1exog3       0.04252006  0.1291588 0.32920764 0.74206810
x1exog2       0.01185438  0.1290754 0.09184073 0.92684309
x1exog1       0.00777347  0.1363643 0.05700519 0.95455252
x1exog4       0.31863627  0.1367881 2.32941597 0.02003661
Dichotomous:
                 Estimate Std. Error    z value     Pr(>|z|)
yhat1          1.26286574  0.7395166  1.7076909 0.0876937093
x2(Intercept)  0.07079775  0.2666447  0.2655134 0.7906139867
x2exog1        0.25092561  0.3126763  0.8025092 0.4222584495
x2exog2        0.22603717  0.2739307  0.8251618 0.4092797527
x2exog5        0.12911922  0.4822986  0.2677163 0.7889176766
x2exog6        0.95609385  0.2823662  3.3860070 0.0007091758
x2exog7       -0.37128221  0.3265478 -1.1369920 0.2555416141
Run Code Online (Sandbox Code Playgroud)