Corr Studies

Posted on Leave a commentPosted in Calculation Lessons, Today I Learned

Tableau 10.2 came out a couple weeks ago and a small but notable feature included in this version of our product is the Corr() and Window_Corr() functions. These calculations compute a coefficient of correlation based on two variables. I’ve done linear algebra in Tableau before, and it’s often quite complicated and looks like this:   The idea with making Corr a simple function in Tableau is to give users a faster and simpler way to find statistical results. But I was confused. correlation coefficients operate on large groups of numbers, so why would it make sense to aggregate a pair of measures with Corr()? How would the aggregation change based on the layout of a Tableau worksheet? And how could I check the results to make sure I was seeing the correlation coefficient I wanted to see? When doing complex calculations, you often get a seemingly arbitrary number as a result, and some faith is required to trust that the number is answering the question you intended to ask, and not a different question. Below are some findings from my Corr studies: A quick preamble about my math background. I was always pretty good at math growing up, but I […]

Podcast: Gartner and Tableau 10.2

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“I really believe that we need to make access to data so easy that it becomes an intrinsic part of conversation – I struggle to think about any organization that hasn’t quite gotten there.” – Wilson Listen in browser:   It’s been a while. Wilson and I have mixed feelings about the annual Gartner reports for B.I. and other enterprise technologies. On one hand, they serve as reliable independent documents that reflect a consultative view of various technical markets. They tend to be progressive enough to point out exciting new technologies and present a fair opinion of all of the companies they evaluate. On the other hand, they are primarily based on customer interviews – which aren’t always particularly progressive. It’s also difficult to tell how much they weigh things unrelated to technology, like company financial health or brand recognition. Their measurements, “ability to execute” and “completeness of vision,” are cryptic and warrant more explanation. This episode starts with a discussion of how we see the space. There’s a lot of focus on visualization, which is great, but it fails to focus on the differences between each technology. I wrote a bit more about this in a recent blog. I read […]