The purpose of error guessing is
to focus the testing activity on areas that have not been handled by the
other more formal techniques, such as equivalence partitioning and
boundary value analysis. Error guessing is the
process of making an educated guess as to other types of areas to be
tested.
For example, educated guesses can be based
on items such as metrics from past testing experiences, or the tester's
identification of situations in the Functional
Design Specification or Detailed Design Specification, that are not
addressed clearly.