abstract = "The selection of appropriate functional form for
describing the relation between two economic variables
has profound implications about the consistency and
significance of estimated model parameters and about
the predictions obtained from such a model. Until
recently, nonparametric approaches have been the only
solution to problems of model identification when the
parametric form of the function is unknown. In the
first part of the dissertation we develop an
implementation of the algorithmic model selection
technique of genetic programming (GP). We illustrate
how it works and offer a brief comparison with
nonparametric estimation methods. In the second part of
the dissertation we specifically address a recent issue
in the GP literature about overfitting and illustrate
how it can be controlled. We also examine GP's ability
to recognize a spurious regression and devise an
illustrate a metric measuring the predictability of a
data set using GP. In the third part of the
dissertation we use GP to model how stock prices react
to unanticipated accounting earnings. The result is a
nonlinear parametric specification of the reaction of
excess current-period stock price returns to the
unexpected component of quarterly earnings. We confirm
the existence of a nonlinear earnings response model
that has superior in-sample and out-of-sample
predictive power over the traditionally employed linear
earnings regression. Our results have several
implications: 1) it is important to incorporate
forecast revisions in the earnings-returns
specification; 2) when the earnings-returns relation is
nonlinear, a nonsymmetric response to earnings
announcements can be achieved even when the earnings
response function itself is symmetric; 3) firms can
affect the size of their earnings response coefficient
by pre-announcing earnings; 4) appropriately accounting
for the nonlinear form of the earnings-returns relation
decreases the abnormal returns associated with earnings
surprises. Our approach suggests an alternative to the
linear earnings-returns relation which may provide
suitable framework for future empirical work.",
notes = "http://www.genealogy.ams.org/id.php?id=118746
Supervisor: Peter Charles Bonest
Phillips