Berry

536 Chapter 16
Comprehensible Output
Tools vary greatly in the extent to which they explain themselves. Rule generators,
tree visualizers, Web diagrams, and association tables can all help.
Some vendors place great emphasis on the visual representation of both
data and rules, providing three-dimensional data terrain maps, geographic
information systems (GIS), and cluster diagrams to help make sense of complex
relationships. The final destination of much data mining work is reports
for management, and the power of graphics should not be underestimated for
convincing non-technical users of data mining results. A data mining tool
should make it easy to export results to commonly available reporting an
analysis packages such as Excel and PowerPoint.
Ability to Handle Diverse Data Types
Many data mining software packages place restrictions on the kinds of data
that can be analyzed. Before investing in a data mining software package, find
out how it deals with the various data types you want to work with.
Some tools have difficulty using categorical variables (such as model, type,
gender) as input variables and require the user to convert these into a series of
yes/no variables, one for each possible class. Others can deal with categorical
variables that take on a small number of values, but break down when faced
with too many. On the target field side, some tools can handle a binary classification
task (good/bad), but have difficulty predicting the value of a categorical
variable that can take on several values.
Some data mining packages on the market require that continuous variables
(income, mileage, balance) be split into ranges by the user. This is especially
likely to be true of tools that generate association rules, since these require a
certain number of occurrences of the same combination of values in order to
recognize a rule.
Most data mining tools cannot deal with text, although such support is starting
to appear. If the text strings in the data are standardized codes (state, part
number), this is not really a problem, since character codes can easily be converted
to numeric or categorical ones. If the application requires the ability to
analyze free text, some of the more advanced data mining tool sets are starting
to provide support for this capability.
Documentation and Ease of Use
A well-designed user interface should make it possible to start mining right
away, even if mastery of the tool requires time and study. As with any complex
software, good documentation can spell the difference between success and
frustration. Before deciding on a tool, ask to look over the manual. It is very