Resources
This paper by Stephen Few for Perceptual Edge looks at three different ways to present data in a graphical format that features change between two points in time.
A line graph with a line for each time series; a range bar graph that begins each time series at the first value and ends at the second value; a bar graph that directly displays the difference between the first and second values in each time series.
Excerpt
"On occasion it is useful to present data that features change between two points in time (e.g., between this year and last year, this quarter and last quarter, this month and last month, and so on). Sometimes this is done in ways that are misleading. For example, viewing change in sales from one day to the next without a series of many days to reveal the nature of routine variation could lead to unnecessary fire drills and even employee terminations in reaction to random variation."
Sources
Few, S., (2014). Displaying Change Between Two Points in Time, Perceptual Edge. Retrieved from: http://www.perceptualedge.com/articles/visual_business_intelligence/displaying_change_between_two_points_in_time.pdf
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