Am I plotting Year-Over-Year Change the best way for a lay audience to understand?

Question

I'm plotting the year-over-year change in my "total war movies" column in Tableau and I noticed something that has made me question if using the year-over-difference on a chart is the best way to represent the change in my data - war movies over time (from 1980-2021). Per my Excel, manual, and Tableau calculations it says that the max change was from 1983 to 1984 where there was a total of 21 movies in 1983 and 35 movies in 1984, a 14 movie increase or a 66.67% change.

However, my confusion lies in that there was a greater difference in total movies from 2006 (76 movies) and 2007 (112 movies) which is a 36 movie increase or a 47.37% change.

I know the percentage change was higher in 1984 than in 2007 but if I want the best representation of increase in war movies over time on a chart is using the max/min values of yoy change the best way to depict this to a lay audience? This is an example of how I can plot it and it's already caused some confusion with a colleague. Any insights are appreciated.

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Answer 1

The 2006 to 2007 increase is smaller than the 1983 to 1984 increase on a percentage basis (even though larger on an absolute basis) since there were more movies in 2006 than in 1983. When a pie is much bigger, cutting a bigger slice may represent cutting a smaller percentage of the pie.

Now, which graph you choose depends on what you are interested in, i.e. do you care about relative changes or absolute changes over time? However, it is worth noting that showing percent changes over time loses some information, whereas showing the number of movies over time is more complete---in particular, it allows one to compute percent changes if so desired.

Answer 2

To decide how to proceed you need to clearly define the question you are trying to answer.

If all you care about is relative growth from year to year you can use percentages.

If you want to be able to compare the growth across your entire time span and between years, showing the total for each year will be more informative.