How Charts Work chapter 14
We must extend the bars to the point at which we begin measuring
- Smith, Alan. How Charts Work (p. 223). Pearson Education. Kindle Edition.
For Magnitude comparison Bar chart’s Axis must start from the beginning of measure.
But, often, the absolute size of something (its magnitude) is not the thing we’re most interested in. We’re frequently more interested in the difference, or – in Visual Vocabulary language – the deviation of things from a known point.
- Smith, Alan. How Charts Work (p. 223). Pearson Education. Kindle Edition.
But often we are frequently more interested in the difference, ie Deviation
The perceptual distortions introduced by not starting the axis at zero become incredibly important. The main takeaway of this cautionary tale of celebrity heights? Charts that represent a “magnitude” comparison should generally start at zero.
- Smith, Alan. How Charts Work (p. 225). Pearson Education. Kindle Edition.
Both points mean that our chart above is concealing information by having its vertical axis anchored to zero, with much of the area of the chart being given to what’s not important and where there is unlikely to ever be any data on display.
- Smith, Alan. How Charts Work (p. 226). Pearson Education. Kindle Edition.
Log scale axis for rapid increase.
- Prevent Extreme Values on a chart obscuring important differences (p 234)
- Exponential Growth (p 235)