Author Archives: Chris Colvin

About Chris Colvin

Chris Colvin is a Lecturer (Assistant Professor) in Economics at Queen’s University Belfast, where he is also a Research Associate at Queen’s University Centre for Economic History.

Mafianomic history

On the Historical and Geographic Origins of the Sicilian Mafia

By Paolo Buonanno, Ruben Durante, Giovanni Prarolo ( and Paolo Vanin



This research attempts to explain the large differences in the early diffusion of the mafia across different areas of Sicily. We advance the hypothesis that, after the demise of Sicilian feudalism, the lack of publicly provided property-right protection from widespread banditry favored the development of a florid market for private protection and the emergence of a cartel of protection providers: the mafia. This would especially be the case in those areas (prevalently concentrated in the Western part of the island) characterized by the production and commercialization of sulphur and citrus fruits, Sicily’s most valuable export goods whose international demand was soaring at the time. We test this hypothesis combining data on the early incidence of mafia across Sicilian municipalities and on the distribution of sulphur reserves, land suitability for the cultivation of citrus fruits, distance from the main commercial ports, and a variety of other geographical controls. Our empirical findings provide support for the proposed hypothesis documenting, in particular, a significant impact of sulphur extraction, terrain ruggedness, and distance from Palermo’s port on mafia’s early diffusion.

Review by Chris Colvin

What are the economic determinants of organised crime? This working paper, written by Paolo Buonanno (University of Bergamo), Ruben Durante (Sciences Po), Giovanni Prarolo and Paolo Vanin (both University of Bologna), attempts to answer this question by looking at the origins of protection rackets on the island of Sicily in the nineteenth century. The authors ask the question: why did the mafia emerge in the west nearly one hundred years before it did elsewhere on the island?

Diego Gambetta, a sociologist at Nuffield College Oxford, has long argued that eastern landlords were better equipped to maintain control as they were present on their lands, whilst western absentee-landlords left their tenants vulnerable to violence by bandits, therefore creating a market for mafiosi. Oriana Bandiera, an economist at the LSE, advances a model that implies that the mafia were more active where landholdings were fragmented. Buonanno et al. add another explanation: there was a high demand for protection in those areas in which citrus crops and sulphur mining were the most important economic activities. These commodities were vulnerable to predatory attacks by bandits when being transported to markets. Property rights on the island were weak, and so areas which specialised in these vulnerable commodities demanded protection services in order to stay in business.

Sketch of a 1901 trial of suspected mafiosi in Palermo (L'Ora, May 1901).

The authors use a sociological survey of Sicily’s mafia conducted in 1900 to code the level of mafia presence at the municipality level. This dataset, which the authors argue has never before been analysed quantitatively, covers more of the island than any other historical source, and does not suffer from the biases inherent in government-collected data. The authors use regression analysis to explain mafia activity with geomorphological (topography), census and road infrastructure data. They find evidence of their hypothesis: the mafia were most present in areas with the right conditions for citric fruits and sulphur extraction. They challenge Bandiera: land fragmentation is not an explanation, but is rather a result of geographic endowment; rugged landscapes lead to small landholdings, which in turn created a demand for mafia services.

Whilst the authors claim to explain the emergence of Sicily’s mafia, I think that they are actually doing something slightly different. Their data on mafia activity refer to 1900, some fifty years after the authors claim that protection racketeers emerged on the island. I think that what they are actually doing is explaining where the mafia was most successful at the end of these 50 years, not where it originated per se. I think that the authors could benefit from using some tools from spatial analysis to strengthen their results. For instance, they could look into spatial autocorrelation, and perhaps need to consider the implications of the fact that western municipalities appear to be much larger than eastern ones. Finally, I think they could be more explicit about how they are addressing the ecological fallacy if they want to prove causality; how do we know that an area’s orange growers and sulphur miners are the ones seeking the mafia protection?

A brief note for those wishing to distribute their working papers using the NEP-HIS email: The working paper reviewed here was added to NEP using the Munich Personal RePEc Archive. This great on-line service allows economic historians with no access to an established institutional working paper series to add their paper directly to the RePEc database.

Electrification, skills and manufacturing

Taking Technology to Task: The Skill Content of Technological Change in Early Twentieth Century United States

By Rowena Gray (



This paper presents a new picture of the labor market effects of technological change in pre-WWII United States. I show that, similar to the recent computerization episode, the electrification of the manufacturing sector led to a “hollowing out” of the skill distribution whereby workers in the middle of the distribution lost out to those at the extremes. To conduct this analysis, a new dataset detailing the task composition of occupations in the United States for the period 1880-1940 was constructed using information about the task content of over 4,000 occupations from the Dictionary of Occupational Titles (1949). This unique data was used to measure the skill content of electrification in U.S. manufacturing. OLS estimates show that electrification increased the demand for clerical, numerical, planning and people skills relative to manual skills while simultaneously reducing relative demand for the dexterity-intensive jobs which comprised the middle of the skill distribution. Thus, early twentieth century technological change was unskill-biased for blue collar tasks but skill-biased on aggregate. These results are in line with the downward trend in wage differentials within U.S. manufacturing up to 1950. To overcome any threat to the exogeneity of the electricity measure, due for example to endogenous technological change, 2 instrumental variable strategies were developed. The first uses cross-state differences in the timing of adoption of state-level utility regulation while the second exploits differences in state-level geography that encouraged the development of hydro-power generation and thus made electricity cheaper. The results from these regressions support the main conclusions of the paper.

Review by: Chris Colvin

What was the effect of electrification on the skill content of manufacturing? Rowena Gray (University of Essex) answers this important question for the case of the US using a new data source and an instrumental variables approach. Gray uses the Dictionary of Occupational Titles, a 1949 publication which describes occupations, to classify the skill content of manufacturing jobs post-electrification. Matching these descriptions with occupational data from decennial censuses and information on plant electrification from the US census of manufacturing, Gray is able to track changes in the skill content of manufacturing due to electrification for the period 1880 to 1940.

Using regression analysis, Gray shows that the most skilled blue-collar workers were displaced by machinery, i.e. electrification resulted in unskilled-biased technical change. She also shows that electrification simultaneously necessitated more clerical and supervisory work, a skill-biased change. This bimodal distributional finding is further strengthened in her robustness exercises, which instrument for electrification using cross-state differences in the timing of the adoption of utility regulation and differences in geography necessary for hydroelectric power generation. This instrumental variable approach is needed to address the concern that electrification is endogenous to the pre-existing skill levels present in state’s labour market; various skillsets may have attracted electrification, rather than the other way around.

Gray’s paper is important because previous studies have been unable to quantify the effects of electrification on the skill content of manufacturing, or at least have been unable to demonstrate that electrification has a distributional effect, that it was simultaneously unskilled- and skilled-biased. An alternative approach to instrumental variables which Gray could have employed to determine the direction of causality would have been to complement her regression analysis with detailed business histories, a method suggested recently by Randall Morck and Bernard Yeung. Where her research potentially suffers is her reliance on post-electrification occupational descriptions; her assumption that the tasks required to carry out particular jobs before and after electrification were identical may be unrealistic. Gray’s future research agenda includes using her individual-level dataset to track cohorts across censuses in order to uncover the winners and losers of electrification. Perhaps another task, which could strengthen the results of the paper discussed here, would be to repeat her analysis using a source that describes the task content of jobs pre-electrification.

Gray’s paper is part of the new working paper series of the European Historical Economics Society. The series, edited by Nikolaus Wolf (Humboldt-Universität zu Berlin), offers the society’s members the chance to disseminate their work ahead of journal submission. Other recent papers in this series include one by Geraldine David and Kim Oosterlinck (Université Libre de Bruxelles) on the effects of the War on the Belgian art market, and a paper by Giovanni Federico (EUI and University of Pisa) on market integration across oceans. This series will surely prove to be an important outlet for work-in-progress by historical economists in future; a paper disseminated in this way could be an important signal of quality versus dissemination through the working paper series of individual institutions.