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AbstractWe establish a relationship between decay centrality and two widely used measures of centrality, namely degree and closeness. We show that for low values of the decay parameter the nodes with maximum decay centrality also have maximum degree, whereas for high values of the decay parameter they also maximize closeness. For intermediate values, we provide sufficient conditions that allow the comparison of decay centrality of different nodes and we show via numerical simulations that in the vast majority of networks, the nodes with maximum decay centrality are characterized by a threshold on the decay parameter below which they belong to the set of nodes with maximum degree and above which they belong to the set of nodes with maximum closeness. We also propose a simple rule of thumb that ensures a nearly optimal choice with very high probability.

This paper develops the concept of policy regime decay to examine what happens when the political foundations of public policies break down. Policy regime decay consists of an erosion of consensus over policy goals, an unraveling of support coalitions, and an exhaustion of institutional capacity to structure the policy process. These elements of decay have observable implications and they inform an empirical strategy for a case study of U.S. food and agriculture policy. Using content analysis of congressional hearings, analysis of legislative roll calls, and policy agenda measures, the paper finds evidence of elite disagreement over nutrition programs, a partisan divide on Farm Bill votes, and a diffusion of committee jurisdiction over food and agriculture issues in Congress. These findings have implications for understanding the policy consequences of polarization, policy feedback effects, and the dynamics of policy regimes.

The "journey to crime," or the study of the distance between an offender's residence and offense site, has been a subject of study within criminology for many years. Implications arising from such research touches the majority of criminological theories. An overriding conclusion from this line of research is that most crimes occur in relatively close proximity to the home of the offender. Termed the distance‐decay function, a plot of the number of crimes that an offender commits decreases with increasing distance from the offender's residence. In a recent paper, Van Koppen and De Keijser raise the concern that inferring individual distance decay from aggregate‐level data may be inappropriate. They assert that previous research reporting aggregated distance‐decay functions conceals individual variations in the ranges of operation, which leads them to conclude that the distance‐decay function is an artifact. We do not question the claim that researchers should not make inferences about individual behavior with data collected at the aggregate level. However, Van Koppen and De Keijser's analysis raises four important issues concerning (1) the interpretation of the ecological fallacy, (2) the assumption of linearity in offender movements, (3) the interpretation of geographic work on profiling, and (4) the assumption of random target selection within a delimited range of operation. Using both simulated and nonsimulated data, we present evidence that reaches vastly different conclusions from those reached by Van Koppen and De Keijser. The theoretical implications of our analyses and possibilities for future research are addressed.

Books reviewed:Tivey, Leonard (edited by Robert Hazell). Constitutional Futures: A History of the Next Ten YearsSeyd, Ben (edited by Robert Blackburn and Raymond Plant). The Politics of the British Constitution; Constitutional Reform: The Labour Government's Constitutional Reform AgendaKlein, Rudolf (Bill Jordan). The New Politics of WelfareO'Brien, David (edited by Dick Leonard). Crosland and New LabourParker, Noel (Maurice Keens‐Soper). Europe in the World: The Persistence of Power PoliticsArnsel, Anja (Peter Gay). My German QuestionArchard, David (edited by Richard Bellamy and Martin Hollis). Pluralism and Liberal NeutralityVosper, Susan Saunders (Robert Service). A History of Twentieth‐century RussiaGarnett, Mark (Luisa Passerini). Europe in Love, Love in Europe: Imagination and Politics in Britain between the WarsJenkinson, Sally L (Bruce Hoffman). Inside Terrorism