frontier_plots

## Error Components Frontier (see Battese & Coelli 1992)
## Inefficiency decreases the endogenous variable (as in a production function)
## The dependent variable is logged
## Iterative ML estimation terminated after 15 iterations:
## log likelihood values and parameters of two successive iterations
## are within the tolerance limit
## 
## final maximum likelihood estimates
##               Estimate Std. Error  z value  Pr(>|z|)    
## (Intercept)  4.6755862  0.0228621 204.5123 < 2.2e-16 ***
## df$sdi_log   0.8303763  0.0237413  34.9761 < 2.2e-16 ***
## df$year1990 -0.0551988  0.0311946  -1.7695  0.076811 .  
## df$year1995 -0.0831680  0.0317424  -2.6201  0.008791 ** 
## df$year2000 -0.0852054  0.0311163  -2.7383  0.006176 ** 
## df$year2005 -0.0460180  0.0310145  -1.4838  0.137873    
## df$year2010 -0.0093178  0.0319003  -0.2921  0.770216    
## sigmaSq      0.5256610  0.0267057  19.6835 < 2.2e-16 ***
## gamma        0.9844945  0.0051557 190.9518 < 2.2e-16 ***
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## log likelihood value: -563.5409 
## 
## cross-sectional data
## total number of observations = 1170 
## 
## mean efficiency: 0.6575449

## Error Components Frontier (see Battese & Coelli 1992)
## Inefficiency decreases the endogenous variable (as in a production function)
## The dependent variable is logged
## Iterative ML estimation terminated after 3 iterations:
## log likelihood values and parameters of two successive iterations
## are within the tolerance limit
## 
## final maximum likelihood estimates
##              Estimate Std. Error z value  Pr(>|z|)    
## (Intercept)  4.743985   0.588474  8.0615 7.536e-16 ***
## df$sdi_log   1.028541   0.836424  1.2297  0.218814    
## df$year1990 -0.085041   0.992980 -0.0856  0.931751    
## df$year1995 -0.099451   0.991800 -0.1003  0.920128    
## df$year2000 -0.110273   0.988629 -0.1115  0.911187    
## df$year2005 -0.091363   0.987394 -0.0925  0.926278    
## df$year2010 -0.068382   0.984733 -0.0694  0.944638    
## sigmaSq      0.567731   0.986697  0.5754  0.565030    
## gamma        0.934298   0.350960  2.6621  0.007765 ** 
## mu          -0.097229   0.983046 -0.0989  0.921213    
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## log likelihood value: -597.9077 
## 
## cross-sectional data
## total number of observations = 1170 
## 
## mean efficiency: 0.6998189