abstract = "This paper describes a technique which can be used
with Genetic Programming (GP) to reduce implicit bias
in binary classification tasks. Arbitrarily chosen
class boundaries can introduce bias, but if individuals
can choose their own boundaries, tailored to their
function set, then their outputs are automatically
scaled into a suitable range. These boundaries evolve
over time as the individuals adapt to the data. Our
system calculates the Evolved Class Boundary(ECB) for
each individual in every generation, with the twin aims
of reducing training times and improving test fitness.
The method is tested on three benchmark binary
classification data sets from the medical domain.
The results obtained suggest that the strategy can
improve training, validation and test fitness, and can
also result in smaller individuals as well as reduced
training times. Our approach is compared with a
standard benchmark GP system, as well as with over
twenty other systems from the literature, many of which
use highly tuned, non-EC methods, and is shown to yield
superior results in many cases.",