Remove NA's from a stacked bar chart created using likertplot function from the HH package

Question

I am creating stacked-bar-charts using the likertplot function from the HH package to display summary results from a recent student survey.

The code I have used to produce this plot is:

likertplot(Subgroup ~ . | Group, data = SOCIETIES_DATA,
       as.percent=TRUE,
       main='Did you attend the City Societies Fair?',
       ylab=NULL,
       scales = list(y = list(relation = "free")),
       between=list(y=0),
       layout = c(1, 5))

Where SOCIETIES_DATA is my dataframe that contains frequency data for the number of students from particular demographics that selected an answer to a single question (in this case if they attended the societies fair). Group is a column for the name of the Demographic categories (e.g. Age, Accommodation) and Subgroup is the categories within the groups (e.g. for Age, <18, 18-20. 21-24 etc.).

Unfortunately I am receiving unwanted NA values values on the second Y axis of the chart for particular variables (in my example, Age and Fee status).

Outputted likert plot from R

My data is formatted the same as it is for other data I have used to create likertplots in the same way, for which I have had no issues. Therefore the error is unlikely to be due to data and thus from the likertplot function.

Most likely, the error is occurring in the scales = argument since this has been affecting the number of NA levels presented in each section of the stacked-bar-chart when editing the code.

I have read through the documentation for the likertplot function in the HH package as well as Heiberger and Robbins (2014) Design of Diverging Stacked Bar Charts for Likert Scales and Other Applications, but have found no solutions to this issue.

The data I have used is presented below.

   Did not attend Yes and poor range of stalls Yes and good range of stalls                                     Subgroup         Group
1             107                           23                          155                                        Halls Accommodation
2              81                            7                           54                                         Home Accommodation
3              10                            2                            5                         Prefer not to answer Accommodation
4              71                           13                           90                 Rented private accommodation Accommodation
5               9                            1                            4                                          <18           Age
6             192                           33                          220                                        18-20           Age
7              37                            6                           64                                        21-24           Age
8              27                            4                           17                                        25-39           Age
9               6                            1                            1                                  40 and over           Age
10              2                            0                            1                         Prefer not to answer           Age
11             29                            6                           57                                           EU    Fee Status
12            195                           31                          198                                         Home    Fee Status
13             34                            8                           43                                International    Fee Status
14             15                            0                            9                         Prefer not to answer    Fee Status
15             48                           10                           59             Arts, Design and Social Sciences       Faculty
16             75                           10                           86                             Business and Law       Faculty
17             34                           12                           64                  Engineering and Environment       Faculty
18             53                            8                           59       Health and Life Sciences - City Campus       Faculty
19             59                            5                           36 Health and Life Sciences - Coach Lane Campus       Faculty
20             52                            6                           61                                   Foundation    Study Mode
21              1                            1                            1                        Postgraduate Research    Study Mode
22             13                            2                           18                          Postgraduate Taught    Study Mode
23            207                           36                          227                                Undergraduate    Study Mode

Any help would be greatly appreciated.

Answer 1

I was able to solve this myself and the answer was actually pretty simple. The categories for each group must be independent. I had the option 'prefer not to say' for both age and Fee status which was causing the error.