Wednesday, March 17, 2010

Absence of Proof is not Proof of Absence!

Francis Bacon (1620) “For a man always believes more readily that which he prefers.” If we leave aside the contentious issue of whether or not it is possible to be a profitable sports trader using a wholly fundamental approach to handicapping, we can readily identify three evidence-based views of ‘form’:
  • Evidence of Presence (EoP),
  • Evidence of Absence (EoA), and
  • Absence of Evidence (AoE).
The natural tendency to confirm our initial opinion leads us to look for supporting evidence (EoP) in both the historical record and in statistical trends with the obvious danger of the logical error of affirming the consequent. By contrast, evidence that eliminates a contender (EoA) is the recommended approach with its natural link to the logically correct method of denying the consequent. Finally, lack of evidence (AoE) neither confirms nor denies the status quo but many neophytes seem to confuse it with EoA.