This brief offers a concise, conceptually grounded analysis of how place-based findings about crime are produced, interpreted, and translated into policy. Anchored in the criminology of place tradition and illustrated through a detailed case study of Mexico City, it introduces the "place specification framework" (PSF), a standard for making explicit the choices that determine what a crime map, hotspot, or ranking of places actually means.

The book starts from one of the field's central achievements, the finding that a small share of places accounts for a disproportionate share of crime, and asks what exactly is being observed when a map appears to show where the problem is. It argues that place-based findings are not self-evident descriptions of urban reality but conditional interpretations that depend on three specification choices: the behavioral setting or unit of place, the link between construct, indicator, and denominator, and the local context or interaction horizon.

Drawing on more than one million victims recorded in criminal investigations and assigned to the city's blocks between 2019 and 2023, the Mexico City case demonstrates that the same city yields different priority places depending on whether victimization is measured as counts, harm, resident-based rates, or exposure-adjusted rates. It also shows how a typology of five block types changes the meaning of the unit of place, how persistence differs between victim counts and harm, and how blocks at the edge of current hotspots are more likely than other blocks to become hotspots the following year.

The final chapter connects analysis to action, showing what the framework changes for hotspot interpretation, cumulative and comparative research, intervention targeting, and policy evaluation. Rather than questioning that crime concentrates or that place matters, the book clarifies the conditions under which place-based patterns become meaningful, comparable, and actionable evidence. With practical implications for urban safety and policy targeting, this book is an essential resource for researchers, analysts, and policymakers interested in the spatial dimensions of crime and evidence-informed intervention.