[Limdep Nlogit List] Calculating Standard Errors for Arc Elasticities
Ana Claudia Sant'Anna
acsantanna at ksu.edu
Thu Mar 9 03:02:07 AEDT 2017
Dear list members,
Following the "Applied Choice Analysis" book 2nd Edition, I am estimating the arc elasticities for dummy attributes in a multinomial logit model using the simulations code, scenario and arc (p. 512-526).
My question is how to calculate the standard errors for these arc elasticities.
Here is the code I am using and the results I am getting:
|-> RPLOGIT ; lhs = choice, cset, alti
; Choices = lease, partner, supply, out, stop
; Model:
U(lease) = a0 + a1*rate + a2*risk + a3*length + a11*more1/
U(partner) = b0 + b2*risk + b3*length + b4* sharepay + b5*trs + b11*more1/
U(supply) = c0 + c2*risk + c3*length + c5*trs + c6*plant + c7*harv + c8*delivery + c9*mbuyall + c11*more1/
U(stop) = d0 + d11*more1
; Full;pwt
; RPM =well, relate
; FCN = a0(n), b0(n), c0(n), d0(n)
; Halton
; Pts = 1000
; Pds = 6
; Maxit = 1000
; Alg = BFGS
; tlb =1e-20
; tlg = 1e-6
; tlf = 1e-20
; output = 1
;simulation;arc
;scenario: mbuyall(supply)=0 & mbuyall(supply)=1
; Parameters
;export=tables$
+---------------------------------------------+
| Random Parameters Logit Model |
| Model Simulation Using Previous Estimates |
| Number of observations 648 |
+---------------------------------------------+
+------------------------------------------------------+
|Simulations of Probability Model |
|Model: Random Parameters Logit 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 648 observations.|
+------------------------------------------------------+
----------------------------------------------------------------------------
Estimated Arc Elasticities Based on the Specified Scenario. Rows in the table
report 0.00 if the indicated attribute did not change in the scenario
or if the average probability or average attribute was zero in the sample.
Estimated values are averaged over all individuals used in the simulation.
Rows of the table in which no changes took place are not shown.
----------------------------------------------------------------------------
Attr Changed in | Change in Probability of Alternative
----------------------------------------------------------------------------
Choice SUPPLY | LEASE PARTNER SUPPLY OUT STOP
x = C9 | -.012 -.014 .178 -.025 -.002
----------------------------------------------------------------------------
-------------------------------------------------------------------------
Specification of scenario 1 is:
Attribute Alternatives affected Change type Value
--------- ------------------------------- ------------------- ---------
MBUYALL SUPPLY Fix at new value .000
-------------------------------------------------------------------------
The simulator located 648 observations for this scenario.
Simulated Probabilities (shares) for this scenario:
+----------+--------------+--------------+------------------+
|Choice | Base | Scenario | Scenario - Base |
| |%Share Number |%Share Number |ChgShare ChgNumber|
+----------+--------------+--------------+------------------+
|LEASE | 18.968 123 | 19.443 126 | .475% 3 |
|PARTNER | 21.290 138 | 21.913 142 | .623% 4 |
|SUPPLY | 11.218 73 | 8.129 53 | -3.089% -20 |
|OUT | 35.834 232 | 37.765 245 | 1.930% 13 |
|STOP | 12.689 82 | 12.749 83 | .061% 1 |
|Total |100.000 648 |100.000 649 | .000% 1 |
+----------+--------------+--------------+------------------+
-------------------------------------------------------------------------
Specification of scenario 2 is:
Attribute Alternatives affected Change type Value
--------- ------------------------------- ------------------- ---------
MBUYALL SUPPLY Fix at new value 1.000
-------------------------------------------------------------------------
The simulator located 648 observations for this scenario.
Simulated Probabilities (shares) for this scenario:
+----------+--------------+--------------+------------------+
|Choice | Base | Scenario | Scenario - Base |
| |%Share Number |%Share Number |ChgShare ChgNumber|
+----------+--------------+--------------+------------------+
|LEASE | 18.968 123 | 18.407 119 | -.562% -4 |
|PARTNER | 21.290 138 | 20.636 134 | -.654% -4 |
|SUPPLY | 11.218 73 | 14.602 95 | 3.384% 22 |
|OUT | 35.834 232 | 33.730 219 | -2.105% -13 |
|STOP | 12.689 82 | 12.626 82 | -.063% 0 |
|Total |100.000 648 |100.000 649 | .000% 1 |
+----------+--------------+--------------+------------------+
The simulator located 648 observations for this scenario.
Pairwise Comparisons of Specified Scenarios
Base for this comparison is scenario 1.
Scenario for this comparison is scenario 2.
+----------+--------------+--------------+------------------+
|Choice | Base | Scenario | Scenario - Base |
| |%Share Number |%Share Number |ChgShare ChgNumber|
+----------+--------------+--------------+------------------+
|LEASE | 19.443 126 | 18.407 119 | -1.037% -7 |
|PARTNER | 21.913 142 | 20.636 134 | -1.277% -8 |
|SUPPLY | 8.129 53 | 14.602 95 | 6.473% 42 |
|OUT | 37.765 245 | 33.730 219 | -4.035% -26 |
|STOP | 12.749 83 | 12.626 82 | -.124% -1 |
|Total |100.000 649 |100.000 649 | .000% 0 |
+----------+--------------+--------------+------------------+
Thank you for your help,
Ana Claudia
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