2. Selecting relevant information
There are a large number of factors which could eVect
the outcome of a football match from the perspective of
one of the teams involved. One of the diYculties in any
investigation of the relationships involved in a given eVect
is that to a large extent the assumption of a particular
model determines the attributes to study and predetermines
the possible relationships that can be found. So, the act of
choosing which model and attributes to study sets a boundary
on what can be discovered.