IF THEN rules can be used for classification
:-
- The IF THEN classification is rule based where the model is
represented as a set of IF THEN rules.
- Example to consider rule1
- if age = youth and person = yes
- then buy_laptop = yes
- If the condition is true for given example then the
precondition is satisfied.
- The IF part of the rule is known as
precondition.And the THEN part is known as rule
consequent. If the result is converted from
decision tree to classification rules. then it can be as
follows.
- Mutually exclusive rules -- If the rules is
independent from each other then it is mutually exclusive rule.
ever record is covered by at most one rule.
- Exhaustive rules -- In this rule each and
every record is covered by at least one rule.
- Use default class to make the rule set
Some performance measures that can be used to evaluate
the accuracy of the rule and difference of these measures
:-
- The rule based classification of IF THEN include --
Rule induction algorithm, Rule ranking measures and Class
prediction algorithm.
- Rule induction algorithm -- It is process of
extracting IF THEN from the data which are directly done using
sequential covering algorithm.
- Rule ranking measures -- This represent some
values which is used to measure usefullness of the rule and provide
accurate prediction.
- The using rule ranking measures improve efficiency and
speed and are used in class prediction algorithm and give
ranking to the rules.
Advantage --
- It is highly expressive as decision trees
- It is easy to generate.
- The performance are comparible to decision
trees.
- It can classify new instance rapidly.
Limiation --
It reduces rules with very small coverage
The next rule can be identical to previous
rule.
Underestimating of accuracy of rules.