Context: There is little empirical knowledge of the effectiveness of the object-oriented paradigm.
Objectives: To conduct a systematic review of the literature describing empirical studies of this paradigm.
Method: We undertook a Mapping Study of the literature.
Results: 138 papers have been identified and classified by topic, form of study involved, and source.
Conclusions: The majority of empirical studies of OO concentrate on metrics, relatively few consider effectiveness.