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微观计量经济学模型ModelofMicroeconometricsdoc
微观计量经济学模型(ModelofMicroeconometrics)
1.1GeneralizedLinearModels
Threeaspectsofthelinearregressionmodelforaconditionallynormallydistributedresponseyare:
(1)Thelinearpredictor
throughwhich
.
(2)
is
(3)
GLMs:
extends
(2)and(3)tomoregeneralfamiliesofdistributionsfory.Specifically,
mayfollowadensity:
:
canonicalparameter,dependsonthelinearpredictor.
:
dispersionparameter,isoftenknown.
Also
and
arerelatedbyamonotonictransformation,
CalledthelinkfunctionoftheGLM.
SelectedGLMfamiliesandtheircanonicallink
Family
Canonicallink
Name
binomial
logit
gaussian
identity
poisson
log
1.2BinaryDependentVariables
Model:
Intheprobitcase:
equalsthestandardnormalCDF
Inthelogitcase:
equalsthelogisticCDF
Example:
(1)Data
Consideringfemalelaborparticipationforasampleof872womenfromSwitzerland.
Thedependentvariable:
participation
Theexplainvariables:
income,age,education,youngkids,oldkids,foreignyesandage^2.
R:
library("AER")
data("SwissLabor")
summary(SwissLabor)
participationincomeageeducation
no:
471Min.:
7.187Min.:
2.000Min.:
1.000
yes:
4011stQu.:
10.4721stQu.:
3.2001stQu.:
8.000
Median:
10.643Median:
3.900Median:
9.000
Mean:
10.686Mean:
3.996Mean:
9.307
3rdQu.:
10.8873rdQu.:
4.8003rdQu.:
12.000
Max.:
12.376Max.:
6.200Max.:
21.000
youngkidsoldkidsforeign
Min.:
0.0000Min.:
0.0000no:
656
1stQu.:
0.00001stQu.:
0.0000yes:
216
Median:
0.0000Median:
1.0000
Mean:
0.3119Mean:
0.9828
3rdQu.:
0.00003rdQu.:
2.0000
Max.:
3.0000Max.:
6.0000
(2)Estimation
R:
swiss_prob=glm(participation~.+I(age^2),data=SwissLabor,family=binomial(link="probit"))
summary(swiss_prob)
Call:
glm(formula=participation~.+I(age^2),family=binomial(link="probit"),
data=SwissLabor)
DevianceResiduals:
Min1QMedian3QMax
-1.9191-0.9695-0.47921.02092.4803
Coefficients:
EstimateStd.ErrorzvaluePr(>|z|)
(Intercept)3.749091.406952.6650.00771**
income-0.666940.13196-5.0544.33e-07***
age2.075300.405445.1193.08e-07***
education0.019200.017931.0710.28428
youngkids-0.714490.10039-7.1171.10e-12***
oldkids-0.146980.05089-2.8880.00387**
foreignyes0.714370.121335.8883.92e-09***
I(age^2)-0.294340.04995-5.8933.79e-09***
---
Signif.codes:
0‘***’0.001‘**’0.01‘*’0.05‘.’0.1‘’1
(Dispersionparameterforbinomialfamilytakentobe1)
Nulldeviance:
1203.2on871degreesoffreedom
Residualdeviance:
1017.2on864degreesoffreedom
AIC:
1033.2
NumberofFisherScoringiterations:
4
(3)Visualization
Plottingparticipationversusage
R:
plot(participation~age,data=SwissLabor,ylevels=2:
1)
(4)Effects
Averagemarginaleffects:
Theaverageofthesamplemarginaleffects:
R:
fav=mean(dnorm(predict(swiss_prob,type="link")))
fav*coef(swiss_prob)
(Intercept)incomeageeducationyoungkids
1.241929965-0.2209318580.6874661850.006358743-0.236682273
oldkidsforeignyesI(age^2)
-0.0486901700.236644422-0.097504844
Theaveragemarginaleffectsattheaverageregressor:
R:
av=colMeans(SwissLabor[,-c(1,7)])
av=data.frame(rbind(swiss=av,foreign=av),foreign=factor(c("no","yes")))
av=predict(swiss_prob,newdata=av,type="link")
av=dnorm(av)
av["swiss"]*coef(swiss_prob)[-7]
av["foreign"]*coef(swiss_prob)[-7]
swiss:
(Intercept)incomeageeducationyoungkids
1.495137092-0.2659758800.8276281450.007655177-0.284937521
oldkidsI(age^2)
-0.058617218-0.117384323
Foreign:
(Intercept)incomeageeducationyoungkids
1.136517140-0.2021795510.6291152680.005819024-0.216593099
oldkidsI(age^2)
-0.044557434-0.089228804
(5)Goodnessoffitandprediction
Pseudo-R2:
asthelog-likelihoodforthefittedmodel,
asthelog-likelihoodforthemodelcontainingonlyaconstantterm.
R:
swiss_prob0=update(swiss_prob,formula=.~1)
1-as.vector(logLik(swiss_prob)/logLik(swiss_prob0))
[1]0.1546416
Percentcorrectlypredicted:
R:
table(true=SwissLabor$participation,pred=round(fitted(swiss_prob)))
pred
true01
no337134
yes146255
67.89%
ROCcurve:
TPR(c):
thenumberofwomenparticipatinginthelaborforcethatareclassifiedasparticipatingcomparedwiththetotalnumberofwomenparticipating.
FPR(c):
thenumberofwomennotparticipatinginthelaborforcethatareclassifiedasparticipatingcomparedwiththetotalnumberofwomennotparticipating.
R:
library("ROCR")
pred=prediction(fitted(swiss_prob),SwissLabor$participation)
plot(performance(pred,"acc"))
plot(performance(pred,"tpr","fpr"))
abline(0,1,lty=2)
●Extensions:
Multinomialresponses
Forillustratingthemostbasicversionofthemultinomiallogitmodel,amodelwithonlyindividual-specificcovariates,.
data("BankWages")
Itcontains,foremployeesofaUSbank,anordere