This paper aims to map HF literature from 1990 to 2014 and it is based on 184 publications. The main criterion for including a publication in the database was that it takes as a starting point and/or comments on the original PHF model. The paper answers the following research questions: 1) what are the research types that are represented in HF literature? and 2) what kind of political-practical arguments and objectives are expressed within each type i.e. orientation?
Nine different types of research were found: 1) comparative studies, 2) guidelines and text books, 3) evaluation reports, 4) commentaries, 5) reviews, 6) implementation and outcome studies, 7) the development of scales and tests, 8) experiences and interaction studies and 9) critical social science research.