A Comparison of Spatially Varying Regression Coefficient Estimates Using Geographically Weighted and Spatial‐Filter‐Based Techniques

Geographically weighted regression (GWR) is a technique that explores spatial nonstationarity in data‐generating processes by allowing regression coefficients to vary spatially. It is a widely applied technique across domains because it is intuitive and conforms to the well‐understood framework of regression. An alternative method to GWR that has been suggested is spatial filtering, which it has been argued provides a superior alternative to GWR by producing spatially varying regression coefficients that are not correlated with each other and which display less spatial autocorrelation. It is, therefore, worthwhile to examine these claims by comparing the output from both methods. We do this by using simulated data that represent two sets of spatially varying processes and examining how well both techniques replicate the known local parameter values. The article finds no support that spatial filtering produces local parameter estimates with superior properties. The results indicate that the original spatial filtering specification is prone to overfitting and is generally inferior to GWR, while an alternative specification that minimizes the mean square error (MSE) of coefficient estimates produces results that are similar to GWR. However, since we generally do not know the true coefficients, the MSE minimizing specification is impractical for applied research.     

International Solidarity in reproductive justice: surrogacy and gender-inclusive polymaternalism

Reproductive justice and gestational surrogacy are often implicitly treated as antonyms. Yet the former represents a theoretic approach that enables the long and racialised history of surrogacy (far from a new or ‘exceptional’ practice) to be appreciated as part of a struggle for ‘radical kinship’ and gender-inclusive polymaternalism. Recasting surrogacy as a dynamic contradiction in itself, full of latent possibilities relevant to early Reproductive Justice militants’ family-abolitionist aims, this article invites scholars in human geography and cognate disciplines to re-think the boundaries of surrogacy politics. As ethnographies of formal gestational workplaces, accounts of gestational workers’ self-organised resistance, and readings of the attendant public media scandals show (taking examples from India, Thailand, and New Jersey), there is no good reason to place these new economies of ‘third-party reproductive assistance’ in a ‘realm apart’ from conversations about social reproduction more generally. Surrogacy, I argue, potentially names a practice of commoning at the same time as it names a new wave of accumulation in which clinicians are capitalising on the contemporary – biogenetic-propertarian, white-supremacist – logic of kinmaking in the Global North. Ongoing experiments in the redistribution of mothering labour (‘othermothering’ in the Black feminist tradition) suggest that ‘another surrogacy is possible’, animated by what Kathi Weeks and the 1970s intervention ‘Wages Against Housework’ conceive as anti-work politics. In making this argument, the article revives the concept ‘gestational labour’ as a means of keeping the process of ‘literal’ reproduction open to transformation.     

Time-Averaging Slows Down Rates of Change in the Archaeological Record

Measuring the pace of cultural change, and understanding its determinants is a fundamental goal of anthropological research. The archaeological record is the main source of information about the pace of cultural change, but it is an imperfect one, as taphonomic loss and mixing distort rate measurements. Here, I focus on the impact of time-averaging on rate measurements. Time-averaging arises when archaeological materials associated with activities and events that took place at different points in time are mixed into the same unit, whether because of depositional processes, disturbance factors, or because archaeologists lump together archaeological contexts when creating analytical units. I use analytical models to show how time-averaging can slow down the observed rates of change under two general modes of cultural change: random drift and directional change. I test this prediction using empirical rates of change from the archaeological record of North America. I show that empirical rates of change are indeed inversely correlated with the duration of time-averaging and provide a range estimate for this correlation.     

Governance,public policy and boundary-making

This symposium draws attention to innovative and emerging research in Australian public policy exploring the interplay of governance, public policy and boundary-making. Conceptually and substantively, boundaries are fundamental to understanding policy outcomes, yet remain overlooked and undertheorised. We aim to contribute to public policy debates, in Australia and beyond, by provoking further reflection on this theme, in particular, the distributive effects of boundaries in policy-making; the blurring of boundaries implicit to governance frameworks; the crossing of boundaries, especially by policy-officials within and between institutions; the construction of boundaries to separate and marginalise; and the existence of temporal–spatial boundaries that demarcate jurisdiction and authority. In short, the study of governance and public policy-making is marked by multiple different types of boundaries but the way in which boundaries get drawn and redrawn is also suffuse with political contestation meaning they raise crucial questions about the exercise of power.