Being “outside the range of normal values” just means being outside the cluster of highly derived variables. I would guess that an actual large or small head would get a more specific mention.

Here’s the abstract for that research:

3D Drawsko: The possibilities and problems with digitizing post-medieval crania in Poland

Blackburn, A.1, Scott, A.1, and T. Betsinger2
1, 2 Department of Anthropology, University of Manitoba, 3Department of Anthropology, SUNY College at Oneonta

The recent development and use of three-dimensional skeletal scans in archaeological populations has become an important analytical tool in biological anthropology. In situations of poor preservation, limited resources, and time constraints, the use of three-dimensional scanning provides an opportunity to capture detailed images of the human skeleton indefinitely for study. The goal of this research is to establish a three-dimensional database of the Drawsko, Poland material to assess various aspects of this unique post-medieval sample (17th-18th centuries). The pilot study for this database project focuses on population affiliation and the deviant “vampire” burials at this site. Cranial measurements were taken on 10 adult individuals (5 males, 5 females) and 1 late adolescent female to assess the cranial variability between individuals in this population and whether the two deviant individuals fell within normal or expected population parameters. It is hypothesized that the two deviant individuals would show cranial disparity when compared to the reminder of the sample, possibly explaining why they were afforded deviant status after death. However, results show a large amount of overall cranial variation within this population, and not just between the two deviant individuals. This overall variation is unexpected, suggesting that Drawsko may have had more genetic admixture than previously assumed, or that this variability is highly influenced by inherent imaging biases. While this study is preliminary in nature, it provides an important theoretical and methodological foundation for the digitization of the Drawsko skeletal sample.