[Limdep Nlogit List] Simulation using estimates from SP data and ASCs from RP data

William Greene wgreene at stern.nyu.edu
Mon Jul 6 05:22:58 AEST 2020


The same subsample,
|-> sample;all$
|-> reject;sprp=1$
is being used for both estimation and simulation.
It sounds like you want to fit the model with one subset of the
data and do the simulation with a different one.  That is OK, just
set the samples accordingly for the two cases.
/B. Greene

On Fri, Jul 3, 2020 at 10:31 PM Thao Thai via Limdep <
limdep at mailman.sydney.edu.au> wrote:

> Hi Nlogit users,
>
> I am simulating some scenarios using the coefficient estimates from a CL
> model on SP data and alternative specific constants (ASCs) calibrated to
> reflect the RP data.
>
> However, the reported market shares in the base case shows the market
> shares observed in SP data. The reported market shares of the simulated
> scenarios are also compared to these SP data market shares, which I think
> is not correct (It should be compared to the market shares from RP data)?
>
> Could you please kindly let me know if my syntax below is correct?
>
> Thank you so much for your help!
> Thao
>
> |-> sample;all$
> |-> reject;sprp=1$
> |-> Nlogit
>     ;lhs = cho, cset, alti
>     ;choices = H, C, P, I, G, N
>     ;crosstabs
>     ;checkdata
>     ;model:
>     U(H) = rl_h1    * RL_H1  + rl_h2  * RL_H2
>     + fl_      * FL_H
>     + cr_h1    * CR_H1  + cr_2  * CR_H2
>     + lo_h1    * LO_H1
>     + sa_      * SA_H
>     /
>     U(C) = com
>     + rl_c1    * RL_C1  + rl_c2  * RL_C2
>     + fl_      * FL_C
>     + cr_c1    * CR_C1  + cr_2  * CR_C2
>     + lo_c1    * LO_C1  + lo_c2  * LO_C2
>     + sa_      * SA_C/
>     U(P) = pri
>     + rl_p1    * RL_P1
>     + fl_      * FL_P
>     + cr_p1    * CR_P1  + cr_2  * CR_P2
>     + lo_p1    * LO_P1  + lo_p2  * LO_P2
>     + sa_      * SA_P/
>     U(I) = ind
>     + rl_i1    * RL_I1  + rl_i2  * RL_I2
>     + fl_      * FL_I
>     + cr_i1    * CR_I1
>     + lo_i1    * LO_I1
>     + sa_      * SA_I/
>     U(G) = gov
>     + rl_g1    * RL_G1
>     + fl_      * FL_G
>     + cr_g1    * CR_G1
>     + lo_g1    * LO_G1
>     + sa_      * SA_G/
>     U(N) = non
>     + rl_n1    * RL_N1
>     + fl_      * FL_N
>     + cr_n1    * CR_N1
>     + lo_n1    * LO_N1  + lo_n2   * LO_N2
>     + sa_      * SA_N
>     $
> +----------------------------------------------------------+
> | Inspecting the data set before estimation.               |
> | These errors mark observations which will be skipped.    |
> | Row Individual = 1st row then group number of data block |
> +----------------------------------------------------------+
> No bad observations were found in the sample
>
> Iterative procedure has converged
> Normal exit:   5 iterations. Status=0, F=    .4001834D+04
>
>
> -----------------------------------------------------------------------------
> Discrete choice (multinomial logit) model
> Dependent variable               Choice
> Log likelihood function     -4001.83388
> Estimation based on N =   2434, K =  32
> Inf.Cr.AIC  =   8067.7 AIC/N =    3.315
> ---------------------------------------
>             Log likelihood R-sqrd R2Adj
> ASCs  only  model must be fit separately
>                Use NLOGIT ;...;RHS=ONE$
> Note: R-sqrd = 1 - logL/Logl(constants)
> ---------------------------------------
> Chi-squared[27]          =    655.81735
> Prob [ chi squared > value ] =   .00000
> Response data are given as ind. choices
> Number of obs.=  2434, skipped    0 obs
>
> --------+--------------------------------------------------------------------
>         |                  Standard            Prob.      95% Confidence
>      CHO|  Coefficient       Error       z    |z|>Z*         Interval
>
> --------+--------------------------------------------------------------------
>    RL_H1|     .07005         .16175      .43  .6650     -.24697    .38707
>    RL_H2|     .23104*        .13433     1.72  .0855     -.03225    .49433
>      FL_|     .17867***      .05585     3.20  .0014      .06920    .28813
>    CR_H1|     .27104**       .13131     2.06  .0390      .01368    .52840
>     CR_2|     .05296         .09477      .56  .5763     -.13279    .23871
>    LO_H1|    -.41466***      .12119    -3.42  .0006     -.65219   -.17713
>      SA_|     .01231***      .00086    14.30  .0000      .01062    .01399
>      COM|    -.10806         .15871     -.68  .4959     -.41913    .20300
>    RL_C1|     .38787**       .16751     2.32  .0206      .05956    .71618
>    RL_C2|     .26364*        .15216     1.73  .0832     -.03459    .56187
>    CR_C1|     .19661         .13691     1.44  .1510     -.07174    .46496
>    LO_C1|    -.22246*        .12854    -1.73  .0835     -.47440    .02949
>    LO_C2|    -.82061***      .15800    -5.19  .0000    -1.13027   -.51094
>      PRI|     .40590***      .14002     2.90  .0037      .13146    .68034
>    RL_P1|     .01672         .12447      .13  .8932     -.22725    .26068
>    CR_P1|     .33357**       .13132     2.54  .0111      .07619    .59095
>    LO_P1|    -.95156***      .14221    -6.69  .0000    -1.23029   -.67282
>    LO_P2|   -1.03276***      .14087    -7.33  .0000    -1.30885   -.75667
>      IND|   -1.11685***      .15286    -7.31  .0000    -1.41645   -.81725
>    RL_I1|     .64312***      .14665     4.39  .0000      .35570    .93054
>    RL_I2|     .79032***      .15550     5.08  .0000      .48555   1.09508
>    CR_I1|     .61024***      .12199     5.00  .0000      .37115    .84933
>    LO_I1|    -.64615***      .12354    -5.23  .0000     -.88828   -.40402
>      GOV|    -.07470         .14043     -.53  .5948     -.34993    .20053
>    RL_G1|    -.33174**       .12927    -2.57  .0103     -.58510   -.07838
>    CR_G1|     .51684***      .12294     4.20  .0000      .27588    .75781
>    LO_G1|    -.57783***      .12464    -4.64  .0000     -.82212   -.33354
>      NON|    -.26651*        .14521    -1.84  .0665     -.55112    .01810
>    RL_N1|    -.08143         .13884     -.59  .5576     -.35355    .19070
>    CR_N1|     .36292***      .13942     2.60  .0092      .08965    .63618
>    LO_N1|    -.58506***      .15904    -3.68  .0002     -.89677   -.27336
>    LO_N2|    -.46639***      .16171    -2.88  .0039     -.78333   -.14945
>
> --------+--------------------------------------------------------------------
> ***, **, * ==>  Significance at 1%, 5%, 10% level.
> Model was estimated on Jul 04, 2020 at 00:17:29 PM
>
> -----------------------------------------------------------------------------
>
> |-> sample;all$
> |-> reject;sprp=1$
> |-> Nlogit
>     ;lhs = cho, cset, alti
>     ;choices = H, C, P, I, G, N/0.23,0.53,0.04,0.04,0.09,0.07
>     ;checkdata
>     ;show
>     'Alg=BFGS
>     ;calibrate
>     ; simulation
>     ; scenario: RL_C1(c)=1/RL_C2(c)=0
>     ;model:
>     U(H) =  rl_h1[0.0700481]    * RL_H1  + rl_h2[0.231038]  * RL_H2
>     + fl_[0.178665]      * FL_H
>     + cr_h1[0.271042]    * CR_H1  + cr_2[0.0529584]  * CR_H2
>     + lo_h1[-0.414659]    * LO_H1
>     + sa_[0.0123069]      * SA_H
>     /
>     U(C) = com
>     + rl_c1[0.387869]    * RL_C1  + rl_c2[0.263637]  * RL_C2
>     + fl_[0.178665]     * FL_C
>     + cr_c1[0.19661]    * CR_C1  + cr_2[0.0529584]  * CR_C2
>     + lo_c1[-0.222456]    * LO_C1  + lo_c2[-0.820609]  * LO_C2
>     + sa_[0.0123069]      * SA_C
>     /
>     U(P) = pri
>     + rl_p1[0.0167174]    * RL_P1
>     + fl_[0.178665]      * FL_P
>     + cr_p1[0.333571]    * CR_P1  + cr_2[0.0529584]  * CR_P2
>     + lo_p1[-0.951557]    * LO_P1  + lo_p2[-1.03276]  * LO_P2
>     + sa_[0.0123069]      * SA_P
>     /
>     U(I) = ind
>     + rl_i1[0.643119]    * RL_I1  + rl_i2[0.790318]  * RL_I2
>     + fl_[0.178665]      * FL_I
>     + cr_i1[0.610239]    * CR_I1
>     + lo_i1[-0.64615]    * LO_I1
>     + sa_[0.0123069]      * SA_I
>     /
>     U(G) = gov
>     + rl_g1[-0.331743]    * RL_G1
>     + fl_[0.178665]      * FL_G
>     + cr_g1[0.516844]    * CR_G1
>     + lo_g1[-0.57783]    * LO_G1
>     + sa_[0.0123069]      * SA_G
>     /
>     U(N) = non
>     + rl_n1[-0.0814267]    * RL_N1
>     + fl_[0.178665]      * FL_N
>     + cr_n1[0.36292]    * CR_N1
>     + lo_n1[-0.585064]    * LO_N1  + lo_n2[-0.466387]   * LO_N2
>     + sa_[0.0123069]      * SA_N$
> +----------------------------------------------------------+
> | Inspecting the data set before estimation.               |
> | These errors mark observations which will be skipped.    |
> | Row Individual = 1st row then group number of data block |
> +----------------------------------------------------------+
> No bad observations were found in the sample
>
>
> Sample proportions are marginal, not conditional.
> Choices marked with * are excluded for the IIA test.
> +----------------+------+
> |Choice   (prop.)| Count|
> +----------------+------+
> |H         .18447|   449|
> |C         .17707|   431|
> |P         .19721|   480|
> |I         .17502|   426|
> |G         .14749|   359|
> |N         .11873|   289|
> +----------------+------+
>
>
> +---------------------------------------------+
> | Discrete Choice (One Level) Model           |
> | Model Simulation Using Previous Estimates   |
> | Number of observations             2434     |
> +---------------------------------------------+
>
> +------------------------------------------------------+
> |Simulations of Probability Model                      |
> |Model: Discrete Choice (One Level) Model              |
> |Simulated choice set may be a subset of the choices.  |
> |Number of individuals is the probability times the    |
> |number of observations in the simulated sample.       |
> |Column totals may be affected by rounding error.      |
> |The model used was simulated with   2434 observations.|
> +------------------------------------------------------+
> -------------------------------------------------------------------------
> Specification of scenario 1 is:
> Attribute  Alternatives affected            Change type             Value
> ---------  -------------------------------  ------------------- ---------
> RL_C1      C                                Fix base at new vlu     1.000
> RL_C2      C                                Fix base at new vlu      .000
> -------------------------------------------------------------------------
> The simulator located   2434 observations for this scenario.
> Simulated Probabilities (shares) for this scenario:
> +----------+--------------+--------------+------------------+
> |Choice    |     Base     |   Scenario   | Scenario - Base  |
> |          |%Share Number |%Share Number |ChgShare ChgNumber|
> +----------+--------------+--------------+------------------+
> |H         | 18.447   449 | 17.950   437 |  -.497%      -12 |
> |C         | 17.707   431 | 19.889   484 |  2.182%       53 |
> |P         | 19.721   480 | 19.142   466 |  -.579%      -14 |
> |I         | 17.502   426 | 17.095   416 |  -.407%      -10 |
> |G         | 14.749   359 | 14.335   349 |  -.415%      -10 |
> |N         | 11.873   289 | 11.589   282 |  -.284%       -7 |
> |Total     |100.000  2434 |100.000  2434 |   .000%        0 |
> +----------+--------------+--------------+------------------+
> _______________________________________________
> Limdep site list
> Limdep at mailman.sydney.edu.au
> http://limdep.itls.usyd.edu.au
>
>

-- 
William Greene
Department of Economics, emeritus
Stern School of Business, New York University
44 West 4 St.
New York, NY, 10012
URL: https://protect-au.mimecast.com/s/fnofCWLVXkU9jgOjF62sjW?domain=people.stern.nyu.edu
Email: wgreene at stern.nyu.edu
Ph. +1.646.596.3296
Editor in Chief: Journal of Productivity Analysis
Editor in Chief: Foundations and Trends in Econometrics
Associate Editor: Economics Letters
Associate Editor: Journal of Business and Economic Statistics


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