No decision is arbitrary if you can find a reason for it. Don’t believe me? Take a look at this figure:
Now ask yourself, what data set was used? What were the endpoints? Why were those endpoints chosen? Why was one period longer than the other? Why were the OLS regressions even calculated over disjoint periods? Why does the image look like that instead of something like:
I sought to find out when I saw this post on Twitter promoting the image. The creator of the image, thingsbreak, and I wound up having a lengthy exchange. I created the second figure above to show how arbitrary decisions can produce dramatically different visual impressions. thingsbreak was not impressed, saying:
Which led to:
He disputed my view that his choices were all “just post hoc rationalization,” resulting in this:
thingsbreak went onto explain his decisions, saying:
I’m not sure which data set “skeptics” favor, but according to thingsbreak, he used an adjusted data set created by Cowtan and Way that was only recently published. I’m guessing that isn’t the favorite of “skeptics.”
Interestingly, the figure I created was from HadCRUT4, the same data set Cowtan and Way adjusted to remove the “cool bias” thingsbreak said is in it. Why would skeptics prefer a recently published adjusted version of a data set to the data set itself? I don’t know. I’m pretty sure thingsbreak just made that claim up.
Anyway, a point I found interesting is thingsbreak’s figure started at 1980. Why? Why did his “[r]ecord before 1998” start at 1980 when we have data for over a hundred years? That question led to the point of this post:
After that tweet, thingsbreak promptly stopped addressing anything topical. Instead, he went into the non-sequitur of why I’m spending so much time on the exchange. I don’t know why, and I certainly don’t know why he quit the exchange soon after with this:
What I do know is thingsbreak created a figure by making a bunch of “arbitrary” decisions. I put arbitrary in quotation marks because, according to him, they weren’t arbitrary – he had a reason for them!