As with conventional definitions of the Neolithic anywhere, the concept in this region relies on there being an agricultural economy, the traces of which are largely indirect. These traces are artefacts interpreted as being linked to agriculture, rather than direct finds of agricultural crops, which are rare in Island Southeast Asia. This definition by artefacts is inevitably polythetic, particularly because many of the sites which have been investigated are hardly comparable. We can expect quite different assemblages from open village sites as opposed to special use sites such as burial caves, or frequentation caves that are used occasionally either by agriculturalists while hunting or by gatherer-hunter groups in some form of interaction with near-by agricultural populations. And rarely is a full range of these different classes of sites available in any one area.