5.8 Multi Dimensional Scaling

For the 23 clean Michelsberg sites we have executed a similar MDS-analysis on the ordinal classes, where we used the Phi coefficient as a measure for dissimilarity. The original data, consisting of 15 variables (artefact types, dimensions), have been reduced to 2 dimensions. For this solution there is an S-value of 0.220. By way of comparison: for the 1-dimensional solution this is S=0.445 and for the 3-dimensional solution S=0.093. The calculations have been performed with the aid of the routine Multiscal from SPSS for Windows. The resulting MDS-diagram can be further improved in two ways. Feedback using the data from the table resulted in the drawing of the 'balloons of differentiating artefact types'. Second, it is useful to display the segment diagrams on the equivalent location in the MDS-diagram.

On the one hand the diagrams do demonstrate how this multivariate analysis works. On the other hand it is clear that no obvious site types may be distinguished on the basis of the presence of associated artefact types. There is, for example, no structure in the data from sites with scrapers, arrowheads and debris only, and other sites with macrolithic artefacts and pottery only. The presence of the various artefact types is loosely connected: the site typology is diffuse.

On the basis of the MDS-diagrams below, the following overlapping site types might be distinguished, moving anti-clockwise:

• a group of 5 sites where pointed blades occur, possibly accompanied by retouched artefacts or axes. Site 52E-121 is here intermediate between this group and the next.
• a group of 5 sites containing macrolithic artefacts only.
• a group of 9 sites with macrolithic artefacts and production debris, accompanied by one or several other artefact types. The 2 large, varied, sites (52E-31 and 52E-150) are part of this group. Their size and range are different, but on the basis of the artefact composition the difference with the intermediate and some small sites is less pronounced. Site 52E-188, intermediate in size and consisting of pottery and a lot of debris, is intermediate between this group and the next.
• a group of 4 sites containing arrowheads, possibly accompanied by debris.