R mlogit() function: Error in if (abs(x - oldx) < ftol) { : missing value where TRUE/FALSE needed

问题

I am having trouble with mlogit() function. I am trying to predict which variables in a given set are the most preferred amongst people who took our survey. I am trying to predict the optimal combination of variables to create the most preferred option. Basically, we are measuring "Name", "Logo Size", "Design", "Theme","Flavor", and "Color".

To do this, we have a large data set and are trying to run it through mlogit.data() and mlogit(), although we keep getting the same error:

Error in if (abs(x - oldx) < ftol) { : missing value where TRUE/FALSE needed

None of my data is negative or missing, so this is very confusing. My syntax is:

#Process data in mlogit.data()

data2 <- 
  mlogit.data(data=data, choice="Choice", 
              shape="long", varying=5:10, 
              alt.levels=paste("pos",1:3))

#Make character columns factors and "choice" column (the one we are 
#measuring) a numeric.

data2$Name <- as.factor(data2$Name)
data2$Logo.Size <- as.factor(data2$Logo.Size)
data2$Design <- as.factor(data2$Design)
data2$Theme <- as.factor(data2$Theme)
data2$Color <- as.factor(data2$Color)
data2$Choice <- as.numeric(as.character(data2$Choice))

##### RUN MODEL ##### 
m1 <- mlogit(Choice ~ 0 + Name + Logo.Size + Design + Theme + Flavor 
+ Color, data = data2)

m1

Does it look like there is a problem with my syntax, or is it likely my data that is the problem?

回答1:

In a panel setting, it is potentially the case that one or more of your choice cards does not have a TRUE value. One fix would be to drop choice cards that are missing a choice.

## Use data.table
library(data.table)

## Drop choice cards that received no choice
data.table[, full := sum(Choice), by=Choice_id]
data.table.full <- data.table[full!=0,]

This is an issue specific to mlogit(). For example, STATA's mixed logit approach ignores missing response variables, R views this as more of an issue that needs to be addressed.

回答2:

I had the same error. It got resolved when I arranged the data by unique ID and alternative ID. For some reason, mlogit requires all the choice instances to be stacked together.

回答3:

Error in if (abs(x - oldx) < ftol) { : missing value where TRUE/FALSE needed

Suggests that if your response variable is binary ie 1/0 then one or more of the values is something other than 1/0

Look at: table(data2$Choice) to see if this is the case

回答4:

I had similar issue, but eventually figured out. In my case, it is due to missing value of the covariates not the choice response.

回答5:

I had this problem when my data included choice situations (questions that participants were asked) in which none of the choices was selected. Removing those rows fixed the problem.

回答6:

Just in case others might have the same issue. I got this error when I did run my choice model (a maximum difference scaling) when I had partial missings. E.g. if two choices per task/set had to be made by the respondent, but only one choice was made.

I could solve this issue in the long format data set by dropping those observations that belonged to the missing choice while keeping the observations where a valid choise was made.

E.g. assume I have a survey with 9 tasks/sets and in each task/set 5 alternatives are provided. In each task my respondents had to make two choices, i.e. selecting one of the 5 alternatives as "most important" and one of the alternatives as "least important". This results in a data set that has 5*9*2 = 90 rows per respondent. There are exactly 5 rows per task*choice combination (e.g. 5 rows for task 1 containing the alternatives, where exactly one of these 5 rows is coded as 1 in the response variable in case it was chosen as the most (or least) important alternative).

Now imagine a respondent only provides a choice for "most important", but not for least important. In such a case the 5 rows for "least important" would all have a 0 in the response variable. Excluding these 5 rows from the data solves the aboove error issue and btw leads to the exact same results as other tools woudl provide (e.g. Sawtooth's Lighthouse software).

来源：https://stackoverflow.com/questions/46840042/r-mlogit-function-error-in-if-absx-oldx-ftol-missing-value-where

标签

mlogit