ApolloChoiceModelling forum

Hi Prof. Stephane, I will provide further explanation here "You have 3 alternatives, but you are only estimating one constant. You can estimate J-1 constants, i.e. 2" If I understand correctly, I must estimate two asc, for example, alternative 1 and 3 as the following code: apollo_beta = c...

Hi Prof. Stephane, I do not get the idea from your response. " first, you should always use a full set (i.e. J-1) alternative specific constants. " With this comment, does it mean that I need to assign, for example, asc of alternative 3 = 0? " But is your third alternative systematica...

Hi Stephane, Thanks for your reply. In this choice experiment, I would like to test the effects of 5 attributes on consumer WTP of biscuits type of flour: wheat flour, BSG flour fibre information: no label, high fibre upcycled information: no label, upcycled logo texture description: no label, crisp...

Dear Professors, In my study, a choice experiment includes 5 attribtues: 4 binary attributes flour, fibre, upcycled, texture and price (4 levels: 25, 40, 55, 70). I have applied MNL as follows # clean rm(list = ls()); graphics.off() # .libPaths("C:/Rpack") library(openxlsx) library(apollo)...

Dear Prof. Hess,

Your explanation is in the page 2, then I did not see this.

Thanks for your explanation.

All the best,

Cuong

Dear Prof. Hess, I have set the estimates from MNL model as the starting values apollo_beta=c(asc_alt3 = -1.99236, mu_b_ing_1 = -0.68717, sigma_b_ing_1 = 0, mu_b_ing_2 = -1.40654, sigma_b_ing_2 = 0, mu_b_fat = -0.19049, sigma_b_fat = 0, mu_b_carb = 0.22643, sigma_b_carb = 0, mu_log_b_price = -2.9301...

Dear Prof. Hess, Below are codes and estimates from MNL model of the same data. The codes # anal. Apollo ------------------------------------------------------------ ### Initialise code apollo_initialise() ### Set core controls apollo_control = list( modelName = "MNL_preference", modelDesc...

Hi, Below is the estimate results Preparing user-defined functions. Testing likelihood function... Overview of choices for MNL model component : alt1 alt2 alt3 Times available 22293.00 22293.00 22293.00 Times chosen 9174.00 8066.00 5053.00 Percentage chosen overall 41.15 36.18 22.67 Percentage chose...

Dear Prof. Hess, I have tried the same approach with the previous one, but different data . In this data, there are 4 binary non-price attributes (ing_1, ing_2, fat, carb) and continuous price attribute. I ran MNL that works well, but when I ran MMNL, the errors/warnings happen agian WARNING : Singu...

Dear Prof. Hess, I have changed the parameters of function apollo_randCoeff in which b_price is also randomed as shown in the following, and then it works apollo_randCoeff = function(apollo_beta, apollo_inputs){ randcoeff = list() randcoeff[["b_barn"]] = mu_b_barn + sigma_b_barn * draws_ba...