[Limdep Nlogit List] WTP space estimation issue

Fri Feb 16 00:32:26 AEDT 2018

Dear Professor Bill and Nlogit users:

I am experiencing some issues regarding a WTP space modelling. In the 
first stage, I estimated the model using a standard RPL model with one 
interaction (in the mean) and everything is fine since the results are 
quite informative for policy making. Nonetheless, to avoid known issues 
related to assuring finite moments for WTP estimations I am trying to 
estimate de model with such interaction in WTP space. When I do that the 
results are very inconsistent and changeable. Any suggestion would be 
very welcome since I am disconcerted.

Here I show the inconsistencies (from my point of view):

Thank you so much in advance

Any suggestion will be highly appreciated

Macario

--------

RPL Output

RPLOGIT

; Lhs = ELE

; cHOICES =A,B,SQ

; RPL=DENS

; FCN=EMI500(N),EMI700(N),ERO14(N),ERO28(N),BIO15(N),BIO20(N),EURC[N]

; MODEL: U(A,B,SQ) = <0,0,ASCSQ>+EMI500*EMI500+EMI700*EMI700+ERO14*ERO14+

ERO28*ERO28+BIO15*BIO15+BIO20*BIO20+EURC*EURC

; pwt; Halton ; pts=1000

; ECM=(A,B)

; pds=PDS

; PAR; margin$

Iterative procedure has converged

Normal exit:64 iterations. Status=0, F=.2066905D+04

--------+--------------------------------------------------------------------

|StandardProb.95% Confidence

ELE|CoefficientErrorz|z|>Z*Interval

--------+--------------------------------------------------------------------

|Random parameters in utility functions..........................

EMI500|2.06088***.243398.47.00001.583842.53793

EMI700|3.26465***.2594912.58.00002.756063.77324

ERO14|1.64629***.246196.69.00001.163762.12882

ERO28|2.90635***.2586211.24.00002.399463.41324

BIO15|.72678***.243842.98.0029.248861.20470

BIO20|.69049***.249902.76.0057.200691.18030

EURC|-.26158***.01361-19.22.0000-.28825-.23492

|Nonrandom parameters in utility functions.......................

ASCSQ|1.75895***.355814.94.00001.061582.45632

|Heterogeneity in mean, Parameter:Variable.......................

EMI5:DEN|-.71829***.26300-2.73.0063-1.23376-.20282

EMI7:DEN|-.85872***.23874-3.60.0003-1.32664-.39079

ERO1:DEN|-.11006.25682-.43.6683-.61341.39330

ERO2:DEN|-.43107*.22683-1.90.0574-.87565.01351

BIO1:DEN|.17070.22053.77.4389-.26152.60292

BIO2:DEN|.38344.242321.58.1136-.09150.85838

EURC:DEN|0.0.....(Fixed Parameter).....

|Distns. of RPs. Std.Devs or limits of triangular................

NsEMI500|.06975.56176.12.9012-1.031291.17079

NsEMI700|.64275**.296852.17.0304.060941.22457

NsERO14|.57823**.274212.11.0350.040801.11567

NsERO28|.97815***.204944.77.0000.576471.37983

NsBIO15|.50831*.269811.88.0596-.020501.03713

NsBIO20|.88335***.215324.10.0000.461331.30536

NsEURC|.16707***.0141911.77.0000.13926.19488

|Standard deviations of latent random effects....................

SigmaE01|-4.98259***.39175-12.72.0000-5.75041-4.21477

--------+--------------------------------------------------------------------

GMX Output

GMXLOGIT

; userp

; Lhs = ELE

; cHOICES = A,B,SQ

; GMX = DENS

; FCN=EMI500(N),EMI700(N),ERO14(N),ERO28(N),BIO15(N),BIO20(N),EURC[*N]

; MODEL: U(A,B,SQ) = <0,0,ASCSQ>+EMI500*EMI500+EMI700*EMI700+ERO14*ERO14+

ERO28*ERO28+BIO15*BIO15+BIO20*BIO20+EURC*EURC

; pwt; Halton ; pts=1000

; ECM=(A,B)

; pds=PDS

; PAR; margin$

Iterative procedure has converged

Normal exit:89 iterations. Status=0, F=.2518070D+04

--------+--------------------------------------------------------------------

|StandardProb.95% Confidence

ELE|CoefficientErrorz|z|>Z*Interval

--------+--------------------------------------------------------------------

|Random parameters in utility functions..........................

EMI500|.09175.27163.34.7355-.44064.62414

EMI700|.02970.18100.16.8697-.32506.38446

ERO14|.11045.37497.29.7683-.62448.84538

ERO28|.09214.19681.47.6396-.29359.47788

BIO15|-.00831.29531-.03.9776-.58710.57049

BIO20|.09172.27327.34.7371-.44388.62733

EURC|1.0.....(Fixed Parameter).....

|Nonrandom parameters in utility functions.......................

ASCSQ|-2.40941***.09551-25.23.0000-2.59661-2.22221

|Heterogeneity in mean, Parameter:Variable.......................

EMI5:DEN|.21937.43417.51.6134-.631601.07034

EMI7:DEN|.21808.31480.69.4885-.39892.83508

ERO1:DEN|.30811.53738.57.5664-.745141.36135

ERO2:DEN|.10758.27105.40.6914-.42368.63883

BIO1:DEN|.50247.51724.97.3313-.511291.51623

BIO2:DEN|.26820.44615.60.5477-.606231.14263

EURC:DEN|-.00690.36556-.02.9849-.72338.70958

|Distns. of RPs. Std.Devs or limits of triangular................

NsEMI500|.0003512.69377.00 1.0000-24.8789824.87968

NsEMI700| .002145.19543.00.9997-10.1807210.18500

NsERO14|.005429.71863.00.9996-19.0427419.05358

NsERO28|.001816.84284.00.9998-13.4099113.41354

NsBIO15|.002237.20629.00.9998-14.1218414.12631

NsBIO20|.005363.29627.00.9987-6.455226.46594

CsEURC|0.0.....(Fixed Parameter).....

|Variance parameter tau in GMX scale parameter...................

TauScale|3.36068***.3161810.63.00002.740983.98038

|Weighting parameter gamma in GMX model..........................

GammaMXL|0.0.....(Fixed Parameter).....

|Coefficient on EURCin preference space form................

Beta0WTP|-177.918200.3959-.89.3746-570.687214.851

S_b0_WTP|16.3943366.1541.04.9643-701.2545734.0430

|Sample MeanSample Std.Dev.................................

Sigma(i)|.351002.53852.14.8900-4.624415.32641

--------+--------------------------------------------------------------------

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