Anyone For Tennis?

One of the biases I identify in my so-called Sacred Manuscript is Recency Bias, defined as:

The tendency to overemphasize the importance of recent experiences or the latest information we possess when estimating future events. Recency bias often misleads us to believe that recent events can give us an indication of how the future will unfold.

It's a strong bias and several markets in team sports I follow reflect this, and while Tennis isn't a sport I follow closely, the well known Tennis Tipster Nishikori noted the other day that:

Betting against a player who has defeated any of the BIG 3 in his previous match has been highly profitable.

This does seem a very reasonable premise, and Nishikori explains his thoughts and analysis in the Tweet linked to above, well worth a read, concluding with this chart:

An excellent analysis in my opinion, but I don't always agree with Nishikori. Earlier this month, he tweeted that:

If you think about it, Betting on Tennis ultimately comes down to assessing the pair "QUALITY vs. FORM" of both players. Easy to say, difficult to do.

While it's always nice and neat to simplify, my thoughts on this were that there are a couple of other parameters to consider, namely "Health and Motivation".

Nishikori replied that he'd include both inside Form, but that seems a stretch to me:

Neither have anything to do with form though. You can be in great form and then get sick or injured or have personal issues arise that impact your motivation.

My definition of 'FORM' in sports betting is a simple one - it's the record of performance in previous events, and specific to tennis, a player's form is one thing, but their health and motivation are unrelated. Yes, if a player gets injured during a previous match, this will be reflected in a lower form rating, but if the injury occurs between matches it won't be reflected. 

As for motivation, this is one of the reasons I mostly stay away from individual sports. In team sports, a player feeling unmotivated for whatever reason will likely not significantly impact the outcome unless they are in a key position such as pitcher or quarterback, but in an individual sport it makes all the difference.