How to lie with your graphs
November 23rd, 2009 by SplineGuy
Stumbled across an interesting little post about 5 ways that you can lie with your graphs. Actually, a better lesson to take from the post is “5 ways other people lie with their graphs and now you can call them on it.”
The post was on Talking Squid, entitled “Five Easy Lies”: Two of the most common ones I’ve seen in talks are below:
- Choose your cutoffs
- Talk about the trend of the trend
“The trend shows no increase for the last [n] days/months/years.”
Don’t mention the previous [20 n] data points.
“Sure the graph is going up for now, but the rate of increase is going down.”
If this fails, talk about the rate of increase of the rate of increase. Keep on differentiating until you find a curve that matches your needs. If all else fails, try logarithms.
The last comment reminds me of Mar’s Law that stumbled upon a couple of days ago:
Everything is linear if plotted log-log with a fat magic marker.
