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When in Rome... On local norms and sentencing decisions

The rule of law in advanced democracies is based on the assumption that the law and its application are the same for all citizens. But research has shown that judges respond to ideology or political biases in their sentencing decisions. This column examines how location can also influence criminal court sentences using data from the US state of North Carolina’s superior court system. It shows that, even after controlling for characteristics of judges, sentencing varies by location and responds to local norms.

The rule of law in advanced democracies is based on the assumption that the law and its application are the same for all citizens. However, we observe wide variations in how criminal judges take into account case-specific characteristics, such as mitigating or aggravating factors, in assigning criminal sentences. Sentences also vary by judge due to differences in ideology or preferences. Finally, sentences may vary spatially: judges may adapt to local norms and practices or may be captured by local interests. While previous literature has concentrated on judges’ individual preferences and biases (Abrams et al. 2012, Blanes i Vidal and Leaver 2011, Lim et al. 2015, Cohen and Yang 2019, Schanzenbach and Tiller 2007)), in our work (Abrams et al. 2019), we explore spatial variations and show how judges respond to local norms when making criminal justice decisions.

The superior court system in North Carolina

Our empirical analysis exploits the unique institutional features of the US state of North Carolina’s superior court system and a rich dataset that includes all criminal justice decisions made in these courts between 1998 and 2010. In this system, judges are subject to elections as well as regular spatial rotation. The state is divided into eight divisions, each of which is subsequently divided into a variable number of districts. Judges are elected in one particular district, but they do not stay there permanently. Every six months, in January and July, judges must change district within their division, according to a schedule determined by the State Chief Justice. 

This unique institutional design allows us to observe judges in different places in different moments of their career and to study how their behaviour evolves by spending time in a new judicial district. Moreover, since judges spend time both in districts where they run for elections and in other districts, we can study whether they behave differently in these two districts.

“When in Rome...”

As a first result, we show that spatial variation in sentencing is prevalent. Figure 1 highlights the fact that spatial variation is as much as important as the variation explained by single judges’ preferences. 

Having established that spatial variation matters, we next study how judges adapt to local circumstances. Our main result shows that judges gradually adapt to local sentencing practices after they arrive in a new district. Specifically, for each judicial district, we compute the average sentence in a crime category given by ‘senior judges’ (judges elected before 1998), who presumably already have good knowledge of the local conditions. We refer to this average sentence at the district crime level as the ‘local sentencing norm’. Restricting the data to decisions made by ‘junior judges’ (judges elected after 1998), for whom we observe the full history of sentencing, we show that the absolute value of the distance between the chosen sentence and the local sentencing norm for a given type of crime decreases with the number of cases examined by the judge in the district. Our results imply that when comparing the hundredth case to the first in any given district, the judge gives a sentence 24 days closer to the local sentencing norm.

Figure 1 Spatial versus judge-level variation in sentencing

Note: The top panel displays district-fixed effects, or spatial variation, in sentencing. The bottom panel displays judicial fixed effects, or judge-level variation, in sentencing. 

This adaptation pattern is present only when judges take decisions outside of the district where they have been elected. This is consistent with the idea that judges are already aware of local sentencing practices in their home district (Figure 2). Digging into the details of the learning process, we document that early sentences made in a district – before learning takes place – are partly determined by the sentencing norm that prevails in the judge’s home district, an indicator of the judge’s intrinsic preferences. When judges from relatively tougher (or more lenient) home districts rotate to a new location, their sentencing converges to the new local sentencing norm from above (or below). 

Figure 2 District experience and sentencing

Notes: Each panel presents results of three separate quantile regressions. In each case, the dependent variable is a measure of the relative severity of sentencing, and the independent variable is the number of cases in a district. The top panel presents results for judges outside their home district; the bottom panel for judges in their home district. Standard errors are clustered at the judge level and error bars indicate the 95% confidence interval 

These results suggest that judges arriving at a new court gradually converge to the local sentencing averages, thus appearing to follow the well-known proverb, “when in Rome, do as the Romans do”. We thus both demonstrate the existence of local sentencing norms and document how judges dynamically adapt to them.

The determinants of local sentencing norms

In the second part of the study, we examine what factors seem to explain variations in the norm. There are three main candidates. Local norms could reflect constraints that district judges take into account (such as constraints on the police force or on prisons), preferences of the population (norms of behaviour and customs), or just a court-specific culture unrelated to fundamental factors. Our analysis suggests that the main driver is local preferences. 

We show that (controlling for district and crime fixed effects) variations in the prevalence of a particular crime in a district decreases average sentences for that crime in that district. We interpret this as the judge adapting to the norm of greater tolerance towards certain types of crimes. In a similar vein, we show a district’s sentencing norms are correlated with a community’s votes in referenda on criminal justice questions. Site-specific variables measuring resource constraints, in particular prison overcrowding, and those trying to capture culture, do not appear to play a role.


Everybody should be treated equally by the law. However, researchers have shown that judges respond to ideology or political biases in their sentencing decisions. In our study we show that, even after controlling for judge characteristics, sentences vary spatially and respond to local norms. To what extent this variation is desirable is a matter of future research. When local norms are the product of local constraints adapting to them may be efficient and desirable. This may be less so when local norms reflect clustering in discriminatory preferences or institutional capture.


Abrams, D S, M Bertrand and S Mullainathan (2012), “Do judges vary in their treatment of race?”, Journal of Legal Studies 41(2): 347-383.

Abrams, D S, R Galbiati, E Henry and A Philippe (2019), “When in Rome... on local norms and sentencing decisions”, CEPR Discussion Paper 13587.

Blanes i Vidal, J, and C Leaver (2011), “Are tenured judges insulated from political pressure?”, Journal of Public Economics 95(7-8): 570-586.

Cohen, A, and Yang, C (2019), “Judicial politics and sentencing decisions”, American Economic Journal: Economic Policy.

Lim, C, B Silveira and J Snyder (2016), “Do judges’ characteristics matter? Ethnicity, gender, and partisanship in Texas state trial courts”, American Law and Economics Review 18(2): 302-357.

Schanzenbach, M M, and E H Tiller (2007), “Strategic judging under the US sentencing guidelines: Positive political theory and evidence”, Journal of Law, Economics and Organization 23(1): 24-56.

Yang, C S (2014), “Have interjudge sentencing disparities increased in an advisory guidelines regime? Evidence from Booker”, NYU Law Review 89(4): 1268-1342.

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