Data

setwd("C:/Users/User/Dropbox/IO")
library(readxl)
df <- read_excel("data_Griliches_Mairesse.xls")
DT::datatable(df)

Observations

  • Компанийн индекс (index)
  • Компанийн үйлдвэрлэлийн салбарын 3 оронтой индекс (sic3)
  • Жил (yr)
  • Борлуулалт (log утгаар, ldsal)
  • Хүний нөөцийн орц (log утгаар, lemp)
  • Капитал (log утгаар, ldnpt)
  • R&D капитал (log утгаар, ldrst)
  • R&D хөрөнгө оруулалт (log утгаар, ldrnd)
  • Капиталын хөрөнгө оруулалт (log утгаар, ldinv)

1

Борлуулалт, Хүний нөөцийн орц, Капитал, R&D капитал, R&Dхөрөнгө оруулалт, Капиталын хөрөнгө оруулалт хувьсагчийн дундаж, вариацыг тус тус ол

1.1

бүх компанийн хувьд

library(dplyr)
sapply(df[,-1:-3], mean)
##    ldsal     lemp    ldnpt    ldrst    ldrnd    ldinv 
## 5.673087 1.259177 4.468996 3.400962 1.787530 2.674828
sapply(df[,-1:-3], var)
##    ldsal     lemp    ldnpt    ldrst    ldrnd    ldinv 
## 3.844412 3.151506 4.912960 4.115928 4.212387 4.710967

1.2

бүх үед ажиглагдсан компаниудын хувьд

df_b <- df %>% 
  group_by(index) %>% 
  filter(n()==4)
dim(df_b)
## [1] 856   9
sapply(df_b[,-1:-3], mean)
##    ldsal     lemp    ldnpt    ldrst    ldrnd    ldinv 
## 6.914288 2.412850 5.915943 4.885773 3.221566 4.068996
sapply(df_b[,-1:-3], var)
##    ldsal     lemp    ldnpt    ldrst    ldrnd    ldinv 
## 3.377599 2.631953 4.232875 3.724434 3.976469 4.223425

1.3

дор хаяж 2 үе ажиглалттай компанийн хувьд

df_c <- df %>% 
  group_by(index) %>% 
  filter(n()>1)
sapply(df_c[,-1:-3], mean)
##    ldsal     lemp    ldnpt    ldrst    ldrnd    ldinv 
## 5.917722 1.505869 4.766525 3.665835 2.018152 2.926110
sapply(df_c[,-1:-3], var)
##    ldsal     lemp    ldnpt    ldrst    ldrnd    ldinv 
## 3.774591 3.008001 4.746978 4.026733 4.216257 4.695677

2

2.1

Баланслагдсан панел датаг (balanced panel) (ө. х өмнөх асуултын (b) түүвэр) ашиглан дараахь моделийг үнэл

\[ldsal_{it} = \beta_1 lemp_{it} + \beta_2 ldnpt_{it} + \beta_3 ldrst_{it} +\beta_4 d78_t + \beta_5 · d83_t + \beta_6 d88_t + \alpha_i + \varepsilon_{it}\]

library(ggplot2)
library(GGally)
ggpairs(data = df_b[, -1:-3],  mapping = aes(color = ldsal),
        upper = list(continuous = "smooth"), lower = list(combo = "facetdensity"),
        diag = list(continuous = "barDiag"))

plot(df_b[,-1:-3])

library(AER) # Эконометрикийн пакэж
library(plm) # Панел регрессийн пакеж
eq <- ldsal ~ lemp + ldnpt + ldrst + ldrnd + ldinv + yr
reg_1 <- plm(eq, data = df_b,
             index = c("index", "yr"),
             model = "pooling",
             effect  = NULL)
reg_2 <- plm(eq, data = df_b,
             index = c("index", "yr"),
             model = "within",
             effect  = "individual")

reg_3 <- plm(eq, data = df_b,
             index = c("index", "yr"),
             model = "random")
summary(reg_1)
## Oneway (individual) effect Pooling Model
## 
## Call:
## plm(formula = eq, data = df_b, effect = NULL, model = "pooling", 
##     index = c("index", "yr"))
## 
## Balanced Panel: n=214, T=4, N=856
## 
## Residuals :
##    Min. 1st Qu.  Median 3rd Qu.    Max. 
## -3.3800 -0.1880  0.0429  0.2540  1.7500 
## 
## Coefficients :
##                Estimate  Std. Error t-value  Pr(>|t|)    
## (Intercept)  2.55807408  0.11282072 22.6738 < 2.2e-16 ***
## lemp         0.44315995  0.03626271 12.2208 < 2.2e-16 ***
## ldnpt        0.51461835  0.03644167 14.1217 < 2.2e-16 ***
## ldrst        0.07822247  0.05767731  1.3562    0.1754    
## ldrnd       -0.07198017  0.05309277 -1.3557    0.1755    
## ldinv        0.00035965  0.03986656  0.0090    0.9928    
## yr78         0.06216295  0.05093461  1.2204    0.2226    
## yr83        -0.01829938  0.05415244 -0.3379    0.7355    
## yr88         0.31905760  0.05238189  6.0910 1.701e-09 ***
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Total Sum of Squares:    2887.8
## Residual Sum of Squares: 233.56
## R-Squared:      0.91912
## Adj. R-Squared: 0.90946
## F-statistic: 1203.23 on 8 and 847 DF, p-value: < 2.22e-16
summary(reg_2)
## Oneway (individual) effect Within Model
## 
## Call:
## plm(formula = eq, data = df_b, effect = "individual", model = "within", 
##     index = c("index", "yr"))
## 
## Balanced Panel: n=214, T=4, N=856
## 
## Residuals :
##    Min. 1st Qu.  Median 3rd Qu.    Max. 
## -1.6700 -0.1010  0.0025  0.1070  1.5700 
## 
## Coefficients :
##       Estimate Std. Error t-value  Pr(>|t|)    
## lemp  0.702198   0.068901 10.1913 < 2.2e-16 ***
## ldnpt 0.016315   0.058042  0.2811   0.77873    
## ldrst 0.345403   0.064996  5.3142 1.486e-07 ***
## ldrnd 0.088757   0.047655  1.8625   0.06300 .  
## ldinv 0.041471   0.035668  1.1627   0.24539    
## yr78  0.081210   0.034682  2.3416   0.01951 *  
## yr83  0.061685   0.043376  1.4221   0.15550    
## yr88  0.255169   0.046934  5.4367 7.752e-08 ***
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Total Sum of Squares:    218.51
## Residual Sum of Squares: 74.622
## R-Squared:      0.65849
## Adj. R-Squared: 0.48771
## F-statistic: 152.807 on 8 and 634 DF, p-value: < 2.22e-16
summary(reg_3)
## Oneway (individual) effect Random Effect Model 
##    (Swamy-Arora's transformation)
## 
## Call:
## plm(formula = eq, data = df_b, model = "random", index = c("index", 
##     "yr"))
## 
## Balanced Panel: n=214, T=4, N=856
## 
## Effects:
##                  var std.dev share
## idiosyncratic 0.1177  0.3431 0.456
## individual    0.1407  0.3750 0.544
## theta:  0.5841  
## 
## Residuals :
##    Min. 1st Qu.  Median 3rd Qu.    Max. 
## -2.4800 -0.1020  0.0167  0.1510  1.1300 
## 
## Coefficients :
##              Estimate Std. Error t-value  Pr(>|t|)    
## (Intercept) 2.8879799  0.1300080 22.2139 < 2.2e-16 ***
## lemp        0.5119974  0.0478084 10.7094 < 2.2e-16 ***
## ldnpt       0.3663215  0.0386222  9.4847 < 2.2e-16 ***
## ldrst       0.0581819  0.0511814  1.1368    0.2560    
## ldrnd       0.0095089  0.0448160  0.2122    0.8320    
## ldinv       0.0494081  0.0344810  1.4329    0.1523    
## yr78        0.0768796  0.0353673  2.1737    0.0300 *  
## yr83        0.0271389  0.0397895  0.6821    0.4954    
## yr88        0.3274173  0.0391204  8.3695 2.377e-16 ***
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Total Sum of Squares:    680.32
## Residual Sum of Squares: 111.23
## R-Squared:      0.83651
## Adj. R-Squared: 0.82771
## F-statistic: 541.711 on 8 and 847 DF, p-value: < 2.22e-16

2.2

phtest(reg_2, reg_3)
## 
##  Hausman Test
## 
## data:  eq
## chisq = 123.11, df = 8, p-value < 2.2e-16
## alternative hypothesis: one model is inconsistent

3