DataViz Diary: Likert Divergent Bar Chart (Before & After)

I think nearly every analyst will be given Likert survey responses at some point and finding interesting ways to visualise them is something of a personal challenge I seem to set myself. Without going into detail the survey looked to understand respondent’s feelings of belonging and use of certain facilities.

Data Prep

Using Tableau Prep it was easy to join the two separate survey CSVs to create a long and thin dataset so a single field provides the questions and responses with a further field stating whether it is from the “Before” or “After” Survey.

Chart Creation

Now I won’t bore you with the multiple steps required but instead point you to Steve Wexler’s post “Likert Scales – The Final Word?” (2011) which explains the necessary steps to create the calculations that determine where the Gantt bars start and the thickness (size) of the bars.

Using the calculations that Wexler advises we can create two versions of the Divergent Bar chart by creating two versions of each calculation, one set with only “Before” values counted with “Else Null” and vice versa. The below visual shows the two sets.

Now all we need to do is simply dual axis the two charts so they overlap and then add our formatting (I like a strong constant reference line at zero to split each side) and any labels to show the end results and % changes.

Conclusion

Originally I was going to only use solid block Gantt lines to show the before responses but thought it wasn’t clear enough. This then led me to experiment with other options and ending with the above which I felt was quite a clear but unobtrusive way to see the changes. The labels and up/down icons provide further insight and clarification too.

Sources

Wexler, S. (2011) “Likert Scales – The Final Word?” Link: https://www.datarevelations.com/resources/likert-scales-the-final-word/