I came across this article discussing how the VIX Flip Indicator tracks the fear of investors. It seems to be an interesting tool, which I would like to investigate. The calculation of this indicator is not communicated in the article. Can you refer me toward its calculation? No good results from Google.
This indicator seems to be similar to William's Vix Fix which is also known as Synthetic Vix.
On plotting the values of Vix Fix, the monthly chart of the S&P 500 looks similar to the chart given in the link shared by you.
Formula: VIX Fix = (Highest (Close,22) – Low) / (Highest (Close,22)) * 100