# Example of fatality rate and beer taxes
open "/Volumes/FLASH DRIVE/EAplicada/Week11_2016/fatality.gdt"
MR = 10000*mrall

# 1982
smpl year==1982 --restrict
ols MR const beertax --robust
smpl --full

# 1988
smpl year == 1988 --restrict
ols MR const beertax --robust
smpl --full

# pooled cs
smpl year == 1988 || year == 1982 --restrict
d88 = year==1988
ols MR const beertax d88 --robust
smpl --full

# first difference
smpl year == 1988 || year == 1982 --restrict
#generate first differences (bw 1988 and 1982)
diff beertax MR
#or using lag operator
genr Dbt=beertax-beertax(-1)
genr Dvf=MR-MR(-1)
smpl --full

smpl year==1988 --restrict
ols d_MR const d_beertax --robust
ols Dvf const Dbt --robust
smpl --full

############################
# deviations from the mean or within estimator: 
smpl year == 1988 || year == 1982 --restrict
#declare a panel
setobs state year --panel-vars
panel MR const beertax --fixed-effects --robust --time-dummies

panel MR const beertax d88 --fixed-effects --robust 
smpl --full

###########################
# including individual dummies
# make sure that state is discrete for gretl:
setinfo state --discrete
smpl year == 1988 || year == 1982 --restrict
ols MR const beertax dummify(state) dummify(year) --robust
smpl --full

# using panel commands for dummies
setobs state year --panel-vars
genr unitdum
genr timedum
smpl year == 1988 || year == 1982 --restrict
ols MR const beertax du_* dt_* --robust
smpl --full

# within estimator with unemployment rate: 
smpl year == 1988 || year == 1982 --restrict
#declare a panel
setobs state year --panel-vars
panel MR const beertax unrate --fixed-effects --robust --time-dummies
smpl --full

# within estimator with additional variables: 
smpl year == 1988 || year == 1982 --restrict
#declare a panel
setobs state year --panel-vars
panel MR const beertax unrate pop --fixed-effects --robust --time-dummies
smpl --full
#############################################################
#Using 3 years: 1982, 1985, 1988

#generate first differences
smpl year == 1982  || year == 1985 || year == 1988 --restrict
diff beertax MR
smpl --full

# FD
smpl year == 1985 || year == 1988 --restrict
ols d_MR const d_beertax --robust
smpl --full

# within estimator
smpl year == 1982  || year == 1985 || year == 1988 --restrict
setobs state year --panel-vars
panel MR const beertax --fixed-effects --robust --time-dummies
smpl --full

# including fixed effects
setinfo state --discrete
smpl year == 1982  || year == 1985 || year == 1988 --restrict
ols MR const beertax dummify(state) dummify(year) --robust
smpl --full

##################################################################
#guns
clear
open "/Volumes/FLASH DRIVE/EAplicada/Week11_2016/Guns.gdt"

# Generate variables
lvio = ln(vio)

ols lvio const shall --robust
ols lvio const shall incarc_rate density avginc pop --robust

setinfo stateid --discrete
ols lvio const shall incarc_rate density avginc pop dummify(year) dummify(stateid) --robust
omit Dyear* --quiet

# within estimator (same as previous)
setobs stateid year --panel-vars
panel lvio const shall incarc_rate density avginc pop --fixed-effects --robust --time-dummies
  

##################################################################
#sindicatos
clear
open "/Volumes/FLASH DRIVE/EAplicada/Week11_2016/wagepan_PSpanel.gdt"
genr expe_sq=exper*exper
freq year

#MODELO LWAGE=THETA_t + Beta Xit +PI*Zi + a_i+u_it

#(a) Interpretation theta and a_i

#(b) sign beta_union

#(c) OLS pool cross sections

ols lwage const dummify(year) union exper expe_sq married black hisp educ --robust

#(d) P Diferencias

diff lwage const union exper expe_sq married black hisp educ

loop foreach i 1981 1982 1983 1984 1985 1986 1987
    genr du_y_$i=year=$i
endloop  

diff lwage const union exper expe_sq married black hisp educ du_y_*

smpl year>1980 --restrict
ols d_lwage d_du_y_* d_union d_exper d_expe_sq d_married --robust

ols d_lwage const du_y_1982 du_y_1983 du_y_1984 du_y_1985 du_y_1986 du_y_1987 d_union d_exper d_expe_sq d_married --robust
u=$uhat

#(e) Given the results corr(a_i,union)

#(f) residual correlation

ols u const u(-1) --robust

#(g) (h)

smpl --full

setobs nr year --panel-vars

panel lwage const union married --fixed-effects --robust --time-dummies

#(i)

panel lwage const union married --random-effects --robust --time-dummies