Statistical bias control in typology

Abstract In this paper, we propose two new statistical controls for genealogical and areal bias in typological samples. Our test case being the effect of VO-order effect on affix position (prefixation vs. suffixation), we show how statistical modeling including a phylogenetic regression term (phylogenetic control) and a two-dimensional Gaussian Process (areal control) can be used to capture genealogical and areal effects in a large but unbalanced sample. We find that, once these biases are controlled for, VO-order has no effect on affix position. Another important finding, which is in line with previous studies, is that areal effects are as important as genealogical effects, emphasizing the importance of areal or contact control in typological studies built on language samples. On the other hand, we also show that strict probability sampling is not required with the statistical controls that we propose, as long as the sample is a variety sample large enough to cover different areas and families. This has the crucial practical consequence that it allows us to include as much of the available information as possible, without the need to artificially restrict the sample and potentially lose otherwise available information.