The research papers in Volume 30 of Tax Policy and the Economy make significant contributions to the academic literature in public finance and provide important conceptual and empirical input to policy design. In the first paper, Gerald Carlino and Robert Inman consider whether state-level fiscal policies create spillovers for neighboring states and how federal stimulus can internalize these externalities. The second paper, by Nathan Hendren, presents a new framework for evaluating the welfare consequences of tax policy changes and explains how the key parameters needed to implement this framework can be estimated. The third paper, a collaborative effort by several academic and US Treasury economists, documents the dramatic increase in pass-through businesses, including partnerships and S-corporations, over the last thirty years. It notes that these entities now generate more than half of all US business income. The fourth paper examines property tax compliance using a pseudo-randomized experiment in Philadelphia, in which those who owed taxes received supplemental letters regarding their tax delinquency. The research explores what types of communication lead to higher rates of tax payment. In the fifth paper, Jeffrey Clemens discusses cross-program budgetary spillovers of minimum wage regulations. Severin Borenstein and Lucas Davis, the authors of the sixth paper, study the distributional effects of income tax credits for clean energy.