Items which are truly boolean data, such as true/false or yes/no answers.
For such data, it is important to devise the meanings (usually questions in subjective data)
carefully, so that the only allowed results are in fact true or false.
The DV_BOOLEAN class should not be used as a replacement for naively modelled
enumerated types such as male/female etc. Such values should be coded, and in
any case the enumeration often has more than two values.

Declaration :

• C++ : class DV_BOOLEAN : public DATA_VALUE
• Java : package class DV_BOOLEAN extends DATA_VALUE

Artifact : DV_BOOLEAN