The Place Specification Framework helps researchers clarify what kind of place-based crime finding they are producing. A hotspot is not a self-defining object. It depends on the spatial unit, outcome construct, exposure base, reference context, and temporal support under which it is identified.

1. What is it?

The Place Specification Framework (PSF) is a framework for making place-based crime analysis more explicit, comparable, and interpretable.

Research on the criminology of place has shown that crime is highly concentrated at micro-geographic units. Yet a place-based finding is never self-interpreting. Its meaning depends on how the analyst defines the spatial unit, the outcome, the exposure base, and the reference context used to compare places.

PSF helps researchers clarify what kind of place-based claim they are making.

It is not a theory of crime. It is a framework for specifying the conditions under which place-based evidence is produced and interpreted.

2. Why place specification matters

A place, and particulalry a hotspot, can mean different things. 

It may refer to:

• A high-volume place in a citywide distribution

• A high-rate place relative to an exposure base

• A high-harm place

• A locally exceptional place relative to nearby places

• A place that predicts future crime

• Or a place selected for operational intervention

These are related claims, but they are not equivalent.

PSF begins from a simple premise:

Place-based findings require explicit specification before they can be interpreted

Without specification, researchers and practitioners may confuse volume with risk, risk with harm, clustering with prediction, or administrative convenience with behavioral relevance.

3. The four specification domains

PSF asks researchers to clarify four core domains.

1. Spatial unit / behavioral setting: What counts as place? Address, street segment, block, facility, grid cell, or neighborhood?

2. Outcome construct: What is being measured? Incidents, victims, calls for service, arrests, harm, or fear?

3. Exposure base: Relative to what denominator or at-risk context? Residents, ambient population, land area, built space, facilities, or targets?

4. Reference context / interaction horizon: Compared to which distribution or nearby context? Citywide ranking, adjacent places, k-nearest neighbors, distance bands, or network catchments?

A fifth condition should also be reported, namely, temporal support, that is, over what period is the finding observed? Temporal support matters because annual concentration, long-term persistence, short-term clustering, and prospective prediction are different empirical claims.

4. What PSF helps distinguish

PSF helps separate different forms of place-based evidence.

• Volume hotspot: A place with a high absolute number of events, victims, or calls

• Exposure-adjusted hotspot: A place with high victimization or crime relative to an exposure base

• Harmspot: A place with high harm-weighted crime burden

• Local-context hotspot: A place that is high relative to nearby places

• Stable local-context hotspot: A place classified as locally hot across alternative interaction horizons

• Prospective hotspot: A place that predicts future concentration

• Intervention target: A place selected for prevention or enforcement under a specific operational objective

The same location may satisfy some of these definitions but not others.

5. Core principle

The core principle of PSF is alignment:

The spatial unit, outcome construct, exposure base, reference context, and temporal support should match the theoretical, empirical, or policy claim being made.

For example:

• If the claim concerns service demand, victim counts or calls for service may be appropriate.

• If the claim concerns risk, an exposure base is needed.

• If the claim concerns local clustering, the interaction horizon must be specified.

• If the claim concerns future targeting, prospective validation is needed.

• If the claim concerns causal effects, the research design must support causal inference.

6. PSF checklist

Researchers using place-based crime data should ask:

1. What is the spatial unit?
   Is it theoretically meaningful, operationally relevant, or mainly data-driven?

2. What outcome is being measured?
   Does the study analyze events, victims, calls, arrests, harm, risk, or perception?

3. Is there an exposure base?
   If so, what denominator is used? If not, is the analysis intentionally count-based?

4. What is the reference context?
   Are places compared against the full citywide distribution, nearby places, similar places, or a temporal baseline?

5. What is the interaction horizon?
   If local context is used, how is “nearby” defined?

6. What is the temporal support?
   Is the finding annual, pooled, persistent, recurrent, short-term, or prospective?

7. What claim is being made?
   Does the interpretation match the specification?

8. What claims are not supported?
   Does the study avoid treating descriptive concentration as causality, risk, or policy effectiveness?

7. Current PSF research agenda

The PSF agenda develops across several related lines of work:

Systematic review

Examines how often hotspot studies explicitly justify spatial units, outcome constructs, and local context.

Exposure and denominator specification

Compares count-based, land-area, and built-space-adjusted measures of victimization concentration.

Global versus local-context hotspotting

Compares citywide rank-based hotspots with local-context hotspots under alternative interaction horizons.

Prospective validity

Evaluates whether different hotspot specifications differ in their ability to predict future victimization.

Theoretical synthesis

Develops the specification problem as a core issue in place-based criminological inference.

Selected publications and replication materials will be added as they become publicly available.

8. Tools and resources

Forthcoming resources will include:

• PSF reporting checklist;

• example tables for methods sections;

• R scripts for hotspot specification sensitivity;

• templates for documenting spatial units, outcomes, denominators, and interaction horizons;

• replication examples from applied crime-and-place research.

Technical materials will be hosted separately at:

carlosvilalta.dev

9. Suggested citation

Suggested citation forthcoming after peer review.

10. Further reading

Anselin, L. (1995). Local indicators of spatial association—LISA. Geographical Analysis, 27(2), 93–115.

Braga, A. A., Turchan, B., Papachristos, A. V., & Hureau, D. M. (2019). Hot spots policing of small geographic areas effects on crime. Campbell Systematic Reviews, 15(3), e1046.

Getis, A., & Ord, J. K. (1992). The analysis of spatial association by use of distance statistics. Geographical Analysis, 24(3), 189–206.

Kwan, M.-P. (2012). The uncertain geographic context problem. Annals of the Association of American Geographers, 102(5), 958–968.

Openshaw, S. (1984). The Modifiable Areal Unit Problem. Geo Books.

Sherman, L. W., Gartin, P. R., & Buerger, M. E. (1989). Hot spots of predatory crime: Routine activities and the criminology of place. Criminology, 27(1), 27–55.

Weisburd, D., Groff, E. R., & Yang, S.-M. (2012). The Criminology of Place: Street Segments and Our Understanding of the Crime Problem. Oxford University Press.

Weisburd, D. (2015). The law of crime concentration and the criminology of place. Criminology, 53(2), 133–157.