Correlation: A Misunderstood Concept in Finance

The linked Google sheets computes the correlation between the _first difference of_ series 1 and the _first difference_ of series 2, and not the correlation between the series 1 and the series 2.

Correlation is indeed misunderstood by the author.

> In the chart above, Series 1 and Series 2 are both increasing every day together in the same direction, yet they are perfectly negatively correlated.

"Perfectly negatively correlated" as in the correlation is ... 0.982306684.