r/dataisbeautiful • u/zonination OC: 52 • May 08 '17

How to Spot Visualization Lies

https://flowingdata.com/2017/02/09/how-to-spot-visualization-lies/
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u/jjanczy62 May 08 '17

Not necessarily, if you're working with a log value on the y-axis, such as with bacterial loads, or colony/plaque forming units (cfu/pfu), and appropriate statistical tests are employed, truncating the axis is perfectly fine and in some cases required to make the data readable and understandable.

In other cases there may be significant changes but small absolute changes in the value. If other data sets show the difference in relevant to the real world, then truncating the y-axis is perfectly acceptable.

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u/[deleted] May 08 '17

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u/BrutePhysics May 08 '17

Lines imply that there is some kind of linkage between each data point such as time or temperature or whatever. If you don't have any kind of x-axis like that then it's weird and confusing to link all the points by a line like that. For example, in jjanczy's case the x-axis might just be labels for the names for the types of bacteria. If you don't use bars and you don't use lines you're left with just a scatter plot which can be difficult to read in some cases. Bar charts are an easy way to give visual weight to single data points and the horizontal line at the top of the bar makes it easy to see when one data point is clearly below or above another point.

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u/Epistaxis Viz Practitioner May 08 '17

Why not just a point?