Section I addresses the measurement of a country's punitiveness in comparing countries' penal policies. It recommends the use of multiple measures of punitiveness in such comparisons; however, this makes the analysis more complex and conclusions more difficult to draw. A table outlines measures of punitiveness under the categories of penal policies, practices, and procedures. Section II focuses on risk and protective factors prevalent in a particular society that can be used in analyzing catalysts related to changes in punitiveness in a country. Section III considers determinants of penal policy in a country. Candidate determinants of penal policy are placed into three categories: nonfactors, risk factors, and protective factors. Nonfactors are developments that occur in every Western country; consequently they cannot provide a basis for explaining widely different policy trends in these countries. Nonfactors include social and economic changes experienced by most developed countries since 1970. These factors lack independent explanatory or causal power. Risk factors come from two sources: case studies of the development of crime control and punishment policies in individual countries and statistical analyses that test hypotheses about correlations between punitiveness and national characteristics and policies not directly associated with crime and punishment. Prominent protective factors that counter overly punitive penal policies include consensus political systems, nonpartisan judges and prosecutors, Francophonic political cultures, and a predominant view that criminal justice policy falls within the province of expert knowledge and professional experience. Section IV, the final section, suggests a number of actions that can make inquiries into comparative penal policy more systematic and resulting generalizations more empirically based. 2 tables, 1 figure, and 108 references