The 100% stacked column
chart is a divided rectangle
that shows the relative proportions
of the parts of one whole.
So it's just like the pie chart,
where it's one whole.
It must add up to one.
It must add up to 100%.
It's representing that
single categorical variable.
It's kind of the bar cookie equivalent
of a pie chart where you've taken
those pieces of the pie and you've rolled
them into a single rectangle and so
you're now comparing the relative
heights of the column.
Why would you choose
between a pie chart and
a stacked column chart,
100% stacked column chart?
If you want to present multiple variables,
and
have the audience make
comparisons between them,
it's probably easier to do that in
stacked columns than in a pie chart.
You must always include 0 on the y-axis.
You must always have 0 as the baseline
in a 100% stacked column.
It's showing the proportions,
it's showing the parts to a whole.
You've got to show the whole.
If you don't show the entire range,
it really will be inaccurate.
And Excel does not seem to know this,
so be sure if you use
the 100% stacked column,
that you double click on the y-axis and
force Excel to set the baseline to 0.
