The RATS Software Forum

First of all, Thank you for your help.

Thanks to your help, I could solve the previous problem "Restriction with SUR model(AIDS case)" problems
It works well. It produce the same coefficient which I expected.
Actually, I replicate it using RATS written by different Statistical Software. (R-language)

I do similar thing in the "Rotterdam model", too.
using same data set, and same method, nonlinsystem,
I exactly follow the introduction in the CONSUMER.RPF example (page UG-141 in RATS v8)

But estimated parameters are different from the originals.
Some of them, has the similar values, but some of them are not.

According to the Original
the estimated parameters are satisfied the economic assumption on Rotteram
for example, for all p[i,i] has the negative value,
and the marginal expenditure share (theta) have all positive sign

but the estimated parameters from RATS has the different situation
1. one of the theta is "negative" this means that it is a inferior goods.
I know that the Rotterdam model assume that the all goods are normal...
the estimated value are violate this assumption.

2. one of the p[i,i] has the positive sign.
this mean that if I compute the estimated elasticity of this good, this good will has positive sign of own price elasticity.
It is of course weird....


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I am not sure what is the problem of this situation.
first of all, I am sure the estimation method of both two are same..I have double checked..
It can be proved by the AIDS cases...it has the exactly same parameter values....

But, the Rotterdam case,,,has the different parameters from the original estimation.
but...parameters in Orignal case are more reasonable thatn...RATSs case..

Any suggestion?
or Can you give any information why this kinds of thing happens...?

You'll have to attach your program and data and indicate which coefficients you think are wrong.

According to the etimation result from R using systemfit package
using the attached data, I have the following coefficient

Rotterdam estimation result from R

theta p1 p2 p3 p4
[1,] 0.10430604 -0.067096490 -0.002333494 -0.010096492 0.083681910
[2,] 0.35081000 -0.002333494 -0.007815808 -0.045823838 0.034702882
[3,] 0.06810146 -0.010096492 -0.045823838 -0.016593741 0.056256779
[4,] 0.37589082 0.083681910 0.034702882 0.056256779 -0.213269207
[5,] 0.01981670 -0.051296545 0.084532565 -0.003824605 -0.002041086
[6,] 0.08107499 0.047141110 -0.063262306 0.020081897 0.040668722
p5 p6
[1,] -0.051296545 0.04714111
[2,] 0.084532565 -0.06326231
[3,] -0.003824605 0.02008190
[4,] -0.002041086 0.04066872
[5,] -0.046517255 0.01914693
[6,] 0.019146925 -0.06377635


But Rotterdam estimation result from R

1. A1 0.112082192 0.050177969 2.23369 0.02550326
2. A2 0.342071335 0.069069224 4.95259 0.00000073
3. A3 0.072226390 0.024797621 2.91263 0.00358395
4. A4 0.577641865 0.129874616 4.44769 0.00000868
5. A5 0.020660674 0.024092951 0.85754 0.39114642
6. P11 -0.048314242 0.071201558 -0.67856 0.49741925
7. P12 -0.019354207 0.000000000 0.00000 0.00000000
8. P13 0.002351814 0.000000000 0.00000 0.00000000
9. P14 0.083164526 0.000000000 0.00000 0.00000000
10. P15 -0.051189134 0.000000000 0.00000 0.00000000
11. P16 0.033341242 0.033816597 0.98594 0.32416102
12. P21 -0.019354207 0.078590008 -0.24627 0.80547476
13. P22 0.050303613 0.132106230 0.38078 0.70336536
14. P23 -0.049399617 0.000000000 0.00000 0.00000000
15. P24 0.008676457 0.000000000 0.00000 0.00000000
16. P25 0.077658916 0.000000000 0.00000 0.00000000
17. P26 -0.067885164 0.047272925 -1.43603 0.15099485
18. P31 0.002351814 0.019821130 0.11865 0.90555116
19. P32 -0.049399617 0.030328222 -1.62883 0.10334833
20. P33 -0.011978183 0.012176771 -0.98369 0.32526733
21. P34 0.052737938 0.000000000 0.00000 0.00000000
22. P35 -0.000589187 0.000000000 0.00000 0.00000000
23. P36 0.006877233 0.014520394 0.47363 0.63576680
24. P41 0.083164526 0.034692407 2.39720 0.01652105
25. P42 0.008676457 0.052046980 0.16670 0.86760269
26. P43 0.052737938 0.016964985 3.10863 0.00187954
27. P44 -0.269346592 0.082259164 -3.27437 0.00105899
28. P45 -0.000071125 0.000000000 0.00000 0.00000000
29. P46 0.124838795 0.042113367 2.96435 0.00303322
30. P51 -0.051189134 0.029449215 -1.73822 0.08217254
31. P52 0.077658916 0.039412549 1.97041 0.04879130
32. P53 -0.000589187 0.011554823 -0.05099 0.95933306
33. P54 -0.000071125 0.017520336 -0.00406 0.99676092
34. P55 -0.048602686 0.024453189 -1.98758 0.04685809
35. P56 0.022793215 0.022420284 1.01663 0.30932774


As I mentioned previous post,
But estimated parameters are different from R, Some of them, has the similar values, but some of them are not.

According to the Original(R)
the estimated parameters are satisfied the economic assumption on Rotteram
for example, for all p[i,i] has the negative value,
and the marginal expenditure share (theta) have all positive sign

but the estimated parameters from RATS has the different situation
1. one of the theta is "negative" this means that it is a inferior goods.
I know that the Rotterdam model assume that the all goods are normal...
the estimated value are violate this assumption.

<<sum of the A1+A2+A3+A4+A5 >0, so..the A6 should have a negative sign to satisfy the homogeneity restriction>>


2. one of the p[i,i] has the positive sign.
this mean that if I compute the estimated elasticity of this good, this good will has positive sign of own price elasticity.
It is of course weird....

<< P22 0.050303613 0.132106230 0.38078 0.70336536>>

The following is the code of estimation I used
I also attached the exel file

You have a typo in your definition of wdq4.

Thank you very much...
I checked that it is same....