Dogs on Tour Redux

A few days ago, I wrote a post extolling the virtues of backing the underdog in the later round of WTA Singles events. Not for the first time in my life, validation and due diligence again confirmed the old chestnut that if something looks too good to be true, it probably is.

The problem in this case was that the raw data I used included prices on walkovers and early retirements, early in this case being prior to the completion of the first set, so returns from such "wins" were in fact null and void. The perils of publishing research findings before they have been peer reviewed. 

The updated results from all WTA events from 2015 to date are below:

Note that I have treated the Round Robin round of the end of season tournaments as Quarter-Finals. 

Quite a come down from the 6%+ ROI originally identified, but at least it ended up in the green.

In complete contrast with the Men in Grand Slams, (I've not yet looked at the ATP tour in full), Semi-Finals are hugely profitable for the underdog Women with an ROI of at least 23%.

While the favourite-longshot bias appears to be missing from the later rounds of the WTA tour, across all rounds, it's there.