ApolloChoiceModelling forum

Hi We are estimating a model in wtp-space. The estimated parameters are sensitive to starting values, and we need to run robustness checks varying the starting values. Is there a command in apollo that automatically repeats the estimation of a model updating the starting values of the parameters? We...

Hi again We tried to remove the ASC from the utility function (alternative1=SQ alternative), and not using the SQ attribute level as base level. We also tried using the SQ attribute levels as base levels, so that alternative1 (SQ) only included the ASC. Neither worked. Are you saying that when the S...

Yes, of course. SB (seabed) takes 3 levels: 30 (only used in alternative 1, SQ), 20, 10 (only used in alternatives 2 & 3, i.e. non-SQ alternatives) SAL (salmon) takes 3 levels: 10 (only used in alternative 1, SQ), 5, 0 (only used in alternatives 2 & 3, i.e. non-SQ alternatives) JOB takes 6 l...

Hi again Sorry for delayed response, it was an misunderstanding between me and the PhD student that runs the model. Attached is the MNL script. Note that we did run it with other starting values as well (only zeros). It does not run. Still the same error message. best regards, Margrethe ### Load Apo...

Hi again yes, sorry for forgetting about the code. Here it is. I also attach the last warning/when running the attached code. ### Load Apollo library install.packages("apollo") library(apollo) ### Initialise code apollo_initialise() ### Set core controls apollo_control = list( modelName = ...

Hi We are dummy coding a model and now the question arises whether we have to exclude the utility function for the status quo (SQ) alternative V[[altSQ]]. For each attribute we use the SQ level as reference level, and there is no variation in level for any of the attributes in the SQ alternative. Th...

Thanks a lot for these insights. It is very useful to have your comments. The reason why we were considering the scale was that the dataset included a split sample, where half of the respondents got one version of the choice cards whereas the other half got another version. Thus we reasoned that the...

Thank you for the very clarifying response. I see the point in keeping to a simpler model compared to more complex when estimating parameters, and the reason I prefer the model in WTP-space is the direct interpretation of the parameters, and not having to think of potential differences in the scale ...

Hello I am running a simple MNL model in WTP space. The model is as follows: V = list() V[["alternative1"]] = b_COST *( asc_SQ + b_SB * SB1 + b_JOB * JOB1 + b_SAL * SAL1 + COST1) V[["alternative2"]] = b_COST *( b_SB * SB2 + b_JOB * JOB2 + b_SAL * SAL2 + COST2) V[["alternativ...

Yes, very helpful indeed!
Thank you.
will try to keep posts to the Forum strictly apollo-related!!
I am very happy that this forum exists.

BR,
Margrethe