Scrap the Bar Chart to Show Changes Over Time
Introducing the slope chart, a handy alternative that does away with extra “noise”
I often see bar charts used to display changes over time, or “before and after” comparisons. While this is a perfectly fine chart to use, there are much more effective and creative ways to display changes between two points in time. One of my favourite ways is to use small multiple slope charts.
The following vertical bar came across my desk a while back. It looks at pre-and post-course evaluations. The chart was clearly done in Excel, as we can see from the lovely (hideous) colour palette it spat out. On first glance, we can see the overall differences between the red and blue categories (pre and post) but actual values are a little more difficult to determine, as there are no guiding grid lines. Our eyes also dart back and forth from the bars to the key to match the categories.
The interesting part about this chart is that there has been a third category added which is the difference between pre and post evaluations (the first two bars). The inclusion of this third bar is adding unnecessary ‘noise’ to the chart…
