ApolloChoiceModelling forum

Hi, The function apollo_deltaMethod will not take into consideration sigma_A2 and sigma_A3 unless you specifically include them in the expression. So when you write: deltaMethod_settings=list(expression=c(WTP_A2="(mu_A2/b_price)", WTP_A3="(mu_A3/b_price)")) apollo_deltaMethod(mod...

Hi Jie, I got your data and script. Your model is not identified. The problem is that no one chooses alternative NB, as detailed below: WARNING: Some alternatives are never chosen in your data! Overview of choices for MNL model component : alt1 alt2 NB Times available 1168.00 1168.00 1168 Times chos...

Hi J, The cross-validation routine in Apollo (apollo_outOfSample) only calculates the LL of each model in- and out-of sample for each repetition, but it does not calculate any measure of fit such as first preference recovery or market share recovery. But what apollo_outOfSample does do is store all ...

Hi, About workInLogs, we are looking into it, but for your case, I do not think you need it, so I would avoid using it. The current problem is probably caused by some remnant identification issue. However, it is very hard to diagnose it without access to your data. If you can, send your data and mod...

Hi, I cannot see any syntax mistake in your code, but I am under the impression that you are over-specifying your model. Remember that for categorical variables with L levels, you need L-1 coefficients. For example, if attribute efficiency hast 4 levels (0, 1, 2, and 3), then you should only include...

Hi Ren, I applied the changes I mentioned in the previous post to your code, and it is running now. Besides moving the "+" signs to the lines above in apollo_randCoeff, I had to remove (comment out) several parameters because they were not influencing the likelihood. See the code below. # ...

Hi Ren, In R, when you are writing an expression across multiple lines, you need to put the connecting operator at the end of an incomplete line. For example, the following expression: x = 2 + 3 + 5 Will cause x to contain the value 10. Instead putting the connecting operator in the second line, as ...

Hi Ren,

Please send it to both

• S.Hess [at] leeds.ac.uk

and

• D.Palma [at] leeds.ac.uk

Best wishes
David

Hi, Thank you for letting us know about this issue. This is indeed a bug in v0.2.8. We will fix it in the next official release, but in the meantime, I created a new version where the bug is fixed. You can download this new version from the links below. Choose the version for your computer's operati...

Hi Lola, From looking at your code, I reckon that your deterministic utility functions are as follows: V_j = a + b_z*z + b_x*x_j Where j is the index of the alternative, and z are sociodemographic characteristics of the respondent. The problem with this formulation is that z variables are the same a...