There are a number of publications dealing with what information systems are, and what information systems research is. From these papers, a number of common findings emerge:
There is often debate on what information systems is (Ives, et al., 1980; Seddon, 1991; Shanks, et al., 1993; Parker, et al., 1994; Holsapple, et al., 1994);
Information systems (IS) has many foundation or reference disciplines (Keen, 1991; Seddon, 1991; Avison, 1993; Holsapple, et al., 1994; Parker, et al., 1994; Walczak, 1999; Galliers, 2004);
IS is located in different university faculties (Avison, 1993; Holsapple, et al., 1994);
IS is perceived as weak on theory (Keen, 1991; Avison, 1993; Straub, et al., 1994; Gregor, 2002);
IS is perceived as practice dominated (Hurt, et al., 1986; Keen, 1991; Avison, 1993, Shanks, et al., 1993);
IS uses many different research methodologies, models or frameworks (Ives, et al., 1980; Avison, 1993, Shanks, et al., 1993; Holsapple, et al., 1994; Parker, et al., 1994; Straub, et al., 1994; Baskerville and Wood-Harper, 1998; Fitzgerald and Howcroft, 1998; Galliers, 2004).
The authors clearly perceive that both the nature and scope of the information systems domain are diverse; the approaches to researching information systems are diverse; the approaches to teaching information systems are diverse and that there is a lack of any single clear theoretical basis for the study of information systems.
The information systems research literature is characterised by only token adoption of any form of subject categorisation, whether proposed as specific to the information systems discipline or imported, with or without adoption, from one of the reference disciplines (Lamp and Milton, 2003). The degree to which an information system is adopted by users has long been used as a determinant of success (DeLone and McLean, 1992) and, in like manner, the lack of adoption of existing categorisation schemes may be seen as an indication of the failure of those subject categorisation schemes.
All of the subject categorisation schemes that have been applied to the information systems domain have had simple hierarchical structures, enforcing a single view of information systems subject categorisation. It could be hypothesised that such a single structured subject categorisation scheme is inadequate to capture the diversity inherent in the information systems domain, resulting in the lack of significant uptake of any of these schemes.
How then can this diversity be expressed in a categorisation scheme? Systems theorists (Ackoff and Emery, 1972; Checkland, 1981; Churchman, 1979) have identified the need to account for diversity, whether expressed as perspectives or as world views, in the models they create. While these approaches reflect the diversity of perspectives in information systems, they deal with different units of analysis. Rather than examining a possibly hypothetical system and the processes and entities that exist in that system, we are examining things that exist in reality, and such a study has its roots in ontology.