Previous research studies the age profile of patent citations to learn about knowledge flows over time. However, identification is problematic because of the collinearity between application year, citation year, and patent age. We show empirically that a patent's ‘citation clock’ does not start until it issues, and propose a highly flexible identification strategy that uses the lag between application and grant as a source of exogenous variation. We examine the potential bias if our assumptions are incorrect, and discuss extensions into other research areas. Finally, we use our method to re-examine prior results on citation age profiles of patents from different technological fields and application year cohorts. Copyright (C) 2009 John Wiley & Sons, Ltd.

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Problem, Research Strategy, and Findings: The Low-Income Housing Tax Credit (LIHTC) is the most common financing mechanism for the production of subsidized housing in America. We investigate how and to what extent states are currently using LIHTC to prepare for and recover from disasters. We systematically code guidelines in the 2017 LIHTC qualified allocation plans from 53 states and territories to identify disaster-related provisions. Twenty-four states and territories include provisions for preparedness or recovery in their allocation plans, of which 13 include only preparedness provisions, three include only recovery provisions, and eight include both types. Preparedness provisions address project design and siting, whereas recovery provisions direct credits to disaster-affected areas or the replacement of damaged units. Using t-tests, we compare three sets of states-those without any disaster-related provisions, those with either preparedness or recovery provisions, and those with both types of provisions-across measures of housing cost, demographic composition, disaster exposure, and political ideology. States with higher homeownership rates, lower home values, and lower rents are more likely than other states to have either or both types of provisions. Future research should investigate why this trend is the case to better inform affordable housing policy. Takeaway for Practice: State governments could mitigate disaster-related hazards and help speed recovery by including locallyrelevant preparedness and recovery provisions in their LIHTC allocation plans. These provisions could incentivize resilient construction, weigh the social costs and benefits of LIHTC construction in floodplains, or waive program rules to address post-disaster housing shortages.

The policing and penal systems play an oversized role in shaping the built environment and budgets of cities, alongside the lives of urban residents. Law enforcement systems are also deeply inequitable with poor residents, and communities of color disproportionately harmed by the violences of the system. Planning’s contribution to the creation of durable spatial stratification in the built environment implicates planning in the class and race disparities in law enforcement systems. Planning research and theory has also supported this inequity by largely neglecting the relationships between policing and penal systems and planning. The articles in this volume address this neglect and employ a wide variety of core theories, methods, and methodologies from planning to engage with the relationships between planning and law enforcement. The articles are connected through attention to racial justice including analyzing moments where planning supported and produced injustice, and identifying opportunities to support greater equity, decarceration and even abolition where planning practice, education and research support the creation of systems of safety and care beyond mass incarceration.

This article analyzes the pedagogy of an urban sociology course taught in prison, with both outside and imprisoned students. The course examined the production of knowledge used in the field of planning and sought to facilitate the coproduction of new insights about urban inequality. Participant observation, focus groups, and students’ written reflections reveal that, in comparison to traditional classroom settings, students explored with greater complexity their embodiment of multiple social identities, wrestled more deeply with the structural embeddedness of individual agency, and situated their personal experiences in a broader theoretical narrative about urban inequality. Building trust in the face of significant power disparities within the classroom was essential to learning. The findings highlight the importance of new locations of learning that enable classrooms to become contact zones, pushing students to collaboratively reimagine justice in the city with those outside the traditional classroom.