3.3 Descriptive Statistics
3.3.1 Study-Related Description
Yet to calculate is not in itself to analyze.
Edgar A. Poe, The Murders in the Rue Morgue, 1841 Herein are contained all tables and graphs which improve the knowledge about study-related variables; i.e., variables which cannot vary within each study. We begin with a summary of the countries related to the studies contained in our data base.
Table 3.7 makes it obvious that the deterrence literature is dominated by authors, data and journals from the United States of America18. More than three quarters of all authors worked in the USA at the time of writing, used U.S. crime data and published in U.S. based journals -even 20.41% of all authors who did not work in the USA at the time of writing used U.S. crime data. This is not unexpected because there are many data sets (crime data and surveys) available for the USA; some starting in the early 1930s (although the reliability of those early data sets is questionable). The United Kingdom, Canada and Germany (and partially Australia) make up for the major part of the rest. Germany, and maybe the Netherlands, seems to be the only non-anglo-saxon country with a relevant portion of published studies. However, this may result from, at least to some extent, the inclusion of German expressions in our search terms.
Table 3.7: Most frequent countries
Country workplace % studied % published %
Australia 16 2.20 13 1.82 4 0.57
Canada 34 4.68 28 3.92 23 3.29
Finland 6 0.83 7 0.98 0 0.00
Germany 22 3.03 19 2.66 31 4.43
Israel 9 1.24 4 0.56 0 0.00
Netherlands 8 1.10 8 1.12 18 2.57
Other 35 4.82 47 6.58 14 2.00
Sweden 6 0.83 9 1.26 3 0.43
Switzerland 8 1.10 8 1.12 1 0.14
United Kingdom 30 4.13 33 4.62 56 8.00
USA 552 76.06 538 75.35 550 78.57
The columns may not sum up to 700, since some studies are written by authors from different countries, analyze different countries simultaneously or the information is not available; only the country of publication is unam-biguously determined. The percentages are calculated from these data and always sum up to one; all deviations are based on rounding.
In fact, from 451 studies which use a public data base, 163 (36.14%) use the Uniform Crime Report (UCR) - the official data base about crime in the USA, compiled by the FBI. The other 63.86% are made up of surveys (e.g., the National Household surveys or National Longitudinal
18To determine the country of publication of a journal, we first referred to the country of the founding editor and, if that information was not available, of the leading editor, the editor who receives the manuscripts, the majority of co-editors or the publisher.
Survey of Youth for the United States), the GermanPolizeiliche Kriminalstatistik(PKS) and other data sets. All other either do not specify the origin of their data, use data collected by themselves (mostly surveys) or use confidential data.
Overall, 848 authors are involved in the 700 studies we have included in our meta-data base.
Most of them appear only once (75.83%) or twice (14.03%). The authors who contribute at least six studies are given intable 3.8: 64 authors (7.55%) contribute three to five studies and are not shown. Merely 2.59% of all authors are involved in 22.71% of all studies. It is not surprising that William C. Bailey and Raymond Paternoster come first, both being sociologists and (Co-) authors of more than 15 studies; the economists Steven D. Levitt and Dale O. Cloninger following close behind. From these top 22 authors only the German Horst Entorf and Finnish Matti Vir´en did not work in the USA at the time of writing.
Table 3.8: Most frequent authors
Author N Author N
Bailey, William C. 20 Piquero, Alex R. 8
Paternoster, Raymond 16 Rasmussen, David W. 8
Levitt, Steven D. 12 Waldo, Gordon P. 8
Cloninger, Dale O. 11 Hakim, Simon 7
Grasmick, Harold G. 10 Witte, Ann D. 7
Ross, Laurence H. 10 Entorf, Horst 6
Benson, Bruce L. 9 Erickson, Maynard L. 6
Nagin, Daniel S. 9 Marvell, Thomas B. 6
Chiricos, Theodore G. 8 Pogarsky, Greg 6
Ehrlich, Isaac 8 Tittle, Charles R. 6
Gibbs, Jack P. 8 Vir´en, Matti 6
All authors with at least 6 contributing studies are listed.
The disciplines of all authors are, more or less, evenly spread (43.23% economists, 40.55% so-ciologists, criminologists and jurists). Regarding the disciplines of the publisher19the relationship is reversed (36.34% and 45.35) which is not surprising, because economists more readily publish in journals outside of their subject than sociologists and criminologists do20. Table 3.9depicts this in more detail.
All in all, the 700 studies we recorded are mostly published in journals (86.29%), followed by working- and conference papers (5.71%) and books (5.57%). 2.43% are not classified. 199 journals publish the 604 journal articles, whereas 120 journals contribute only a single article; the major part, namely 326 articles (53.97%), stem from just 25 journals (12.56%) and are shown in table 3.10. The Criminology-Journal stands out by contributing 30 studies, fifty percent more than
19This can be, for example, a journal, a department or an institution.
20Jurists are an exception here: 27% of their studies are published in economic media, which is the largest cross-discipline share of all. However, this cross-discipline just appears in 26 studies in our meta-data base.
Table 3.9: Disciplines of authors and publishers
Publisher discipline Author discipline
Law Crim. Econ. Soc. Psych. Other Sum
Law 7 7 15 5 1 2 37
Criminology 8 43 15 64 3 10 143
Economics 7 1 207 10 2 12 239
Sociology 2 15 22 80 2 13 134
Psychology 0 0 0 5 12 3 20
Other 2 7 29 11 8 44 101
Undefined 0 0 3 0 0 0 3
Sum 26 73 291 175 28 84 677
While all disciplines of the publisher are classified, some authors could not be categorized (the missing 23 studies).
Discipline of the publisher is unique while multiple authors can contribute multiple disciplines to a study-entry.
the second most frequent journal. All major disciplines are present in the top five (except the law discipline, which first appears in the 13th place). The listed journals make up for 43.75% of all law articles, 76.19% of all criminological, 53.08% of all economic, 67.2% of all sociological and 28.89% of all other journal articles.
The oldest study in our data base was published 1952, the newest in 2006. Not surprisingly, the data used in the studies is older, since it requires some time to collect and analyze the data, newer data is not available or simply not of interest. Some studies are even especially interested in old data (e.g., those which include data from the 19th century). The distributions of the year of publication and the mean year21 of the used data are shown infigure 3.1. The median time span, conditional on multiple points of time, is exactly 120 months.
A steady stream of empirical studies about deterrence started in the late sixties, reaching a first peak in the late seventies with the heated discussion fueled byEhrlich(1973) andEhrlich(1975a).
With the exception of some years, the number of publications slowly receded until the mid nineties when it reached new heights and kept its pace until today.
The steady flow of studies can, at least partially, be viewed under two different aspects: a dimin-ishing interest in the deterrence research and a larger acceptance of deterrent measures in other fields of research (like unemployment inSmith et al.(1992); Witt et al.(1998) orLevitt (2001)) to minimize an omitted variable bias. This can be verified by figure 3.2. The number of studies which use deterrence variables only as covariates can be interpreted as a lower bound, because we classified deterrence variables as covariates only in the case the authors do not interpret22 the corresponding coefficients. Furthermore, studies which do not focus on deterrence but include deterrence measures as covariates had a lower probability to be detected during our research.
21The mean year is the mean of the first and last year the data refers to, which is available for 593 studies.
22For example, if the effect of unemployment on crime is the focus of the study but the authors spend a considerable amount of space on interpreting the negative effect of the arrest rate as a deterrent factor, the according observation
Table 3.10: Most frequent journals
Journal n category
Criminology 30 criminology
Journal of Law and Economics 20 economics
Law and Society Review 19 sociology
Applied Economics 17 economics
Accident Analysis and Prevention 17 other
Journal of Criminal Justice 16 criminology
Journal of Criminal Law and Criminology 16 criminology
American Economic Review 15 economics
American Sociological Review 15 sociology
Journal of Research in Crime and Delinquency 15 criminology
Social Forces 14 sociology
Social Science Quarterly 14 sociology
Journal of Legal Studies 14 law
American Journal of Economics and Sociology 12 sociology
Review of Economics and Statistics 12 economics
Social Problems 10 sociology
Economic Inquiry 10 economics
Journal of Quantitative Criminology 9 criminology
Journal of Studies on Alcohol 9 other
Southern Economic Journal 8 economics
International Review of Law and Economics 8 economics
Journal of Public Economics 8 economics
Crime and Delinquency 7 criminology
Journal of Political Economy 7 economics
Journal of Behavioral Economics 7 economics
All journals with at least 7 contributing studies are listed.
The kind of data employed is spread rather evenly over the major categories - time series, cross sections, surveys and panel data (in that order) - while experiments appear only sparsely.
Aggregated, almost two thirds (65.81%) is “typical” crime data, while 23.87% and 9.16% is survey and experimental data. Consequently, this is also reflected by the studied objects: counties, states, people and nations (in that order) are studied in most cases. 61.96% of all studies implement regional data and 30.49% of the data is derived from people and groups. These observations are visualized infigure 3.3.
We also included several variables to catch some quality related measures for each study. From some of these, we constructed a quality index starting at 0 (neither the author nor the reader report any problems) and ending at 8 (author and reader report major problems in the study).
Summarizing these into three categories, we can say that 189 studies (27%) are rather flawless, 438 do contain some problems (62.57%) and 73 studies are problematic (10.43%). We stress that
in our meta-data base is not considered being only a covariate.
Figure 3.1: Year of publication and used data
010203040Frequency
1940 1950 1960 1970 1980 1990 2000
Year, cut at 1940
Year of publication Mean year of used data
Based on own meta−data base
Year of publication and mean year of used data
this measure should not be overrated, because it is not easy to decide how many problems a study may have and how severe they are - it depends heavily on what the author does, reports and how frankly he is to the reader. Eventually, there is no such thing like a flawless empiric study without any problems.
Finally, we want to report that 79% of all studies use covariates and, therefore, control for other influences. Intable 3.11, we show the key statistics of the number of results (i.e., the observations in our meta-data base) reported in the studies.