Way back in college, while taking a course in statistics, I had to read a great book called “How to lie with statistics”.  It was fascinating.  It seems the Covid scientists in Kansas have read that book.  They held a press conference and showed graphs that attempted to show the correlation of wearing masks with new cases of Covid (1).  Here is their chart:

The data are pretty convincing, right?  It shows that beginning on the 25th of July, those counties with the mask ordinance showed dramatic reductions in the number of new Covid cases.

But, wait a minute.  Notice something?  Yes, there are actually TWO y-axes!  (Who in the world though of that!)  The “Mask-mandatory” y-axis on the left hand side goes from 15 – 25 while the “No masks required” y-axis on the right hand side goes from 4 – 14.  Those data are not that far off so why did they do that?  (Normally, when people use two different y-axes there is a large disparity on the ranges such as comparing the stock price of a stock from $10 – $20 per share versus one that ranges from $1,000 – $2,000 per share.)

But, some sharp-eyed people noticed this and under the Freedom of Information act got the data and remade the graph to be more honest. n addition to the two y-axes, the big thing they noticed is that the public policy people in Kansas who developed the chart and held the press conference cherry-picked the data. Here is the revised graph and one can only draw much different conclusions:

  1. In the week the mandate when into effect, the number of cases rose significantly faster in the mask-mandated counties than in the non-mask-mandated counties.
  2. To make their case seem stronger, the conveniently picked July 12 for their graph to make is seem like their point is valid.

When confronted with their mis-leading information, the public health people in Kansas said “We stand behind our data”.  Well, I hope so.  But, what they didn’t stand behind is their interpretation of the data and the way they tried to manipulate the data to agree with their narrative that wearing masks prevent the spread of Covid.

(1) This article is based on a fabulous article by Allysia Finley of the Wall Street Journal.  A pdf of that article is here.