148 Comparative Method

COMPARATIVE METHOD

The comparative method is fundamentally a case­oriented, small-N technique. It is typically used when researchers have substantial knowledge of each case included in an investigation and there is a relatively small number ofsuch cases, often ofnecessity. The best way to grasp the essential features of the comparative method is to examine it in light ofthe contrasts it offers with textbook presentations of social science method­ology. In textbook presentations, (a) the proximate goal of social research is to document general pat­terns that hold for a large population of observations, (b) cases and populations are typically seen as given, (c) researchers are encouraged to enlarge their number of cases whenever possible, (d) it is often presumed that researchers have well-defined theories and well­formulated hypotheses at their disposal from the very outset of their research, (e) investigators are advised to direct their focus on VARIABLES that display a healthy range of variation, and (f) researchers are instructed to assess the relative importance of competing indepen­dent variables to understand causation.

PROXIMATE GOALS

Textbook presentations of social research usually focus on the goal of documenting general patterns characterizing a large population of observations. If researchers can demonstrate a relationship between one or more independent variables and a DEPENDENT

VARIABLE, then they can better predict cases' values on the dependent variable, given knowledge of their scores on the predictor variables. Typically, the study ofgeneral patterns is conducted with a sample ofobser­vations drawn from a large population. The researcher draws inferences about the larger population based on his or her analysis of the sample.

By contrast, COMPARATIVE RESEARCH focuses not on relationships between variables or on problems of inference and prediction but on the problem of making sense of a relatively small number of cases, selected because they are substantively or theoretically impor­tant in some way (Eckstein, 1975). For example, a researcher might use the comparative method to study a small number of guerilla movements in an in-depth manner. Suppose these movements were all thought to be especially successful in winning popular sup­port. To find out how they did it, the researcher would

conduct in-depth studies of the movements in question. This case-oriented comparative study would differ dra­matically from a "textbook" study. In the latter, the researcher would sample guerilla movements from the population of such movements (assuming this could be established) and then characterize these movements in terms of generic variables and their relationships (e.g., the correlation between the extent of foreign financial backing and the degree of popular support).

As these examples show, the key contrast is the researcher's proximate goal: Does the researcher seek to understand specific cases or to document general patterns characterizing a population? This contrast fol­lows a longstanding division in all of science, not just social science. Georg Henrik von Wright (1971, pp. 1-33) argues in Explanation and Understanding that there are two main traditions in the history of ideas regarding the conditions an explanation must sat­

incisfy to be considered scientifically respectable. One (W[tradition, which he calls "finalistic," is anchored in

the problem of making facts understandable. The the

other, called "causal-mechanistic," is anchored in anG tin(the problem of prediction. The contrasting goals of evicomparative research and "textbook" social research

closely parallel this fundamental division. my thr' gat

CONSTITUTION OF CASES aniAND POPULATIONS

sci Textbook presentations of social science methodo­

logy rarely examine the problem of constituting cases Nand populations. The usual case is the individual survey respondent; the usual population is demarcated by geo­graphic, temporal, and demographic boundaries (e.g., re:

adults in the United States in the year 2003). The key in

textbook problematic is how to derive a representative th

sample from the very large population of observations m th

By contrast, comparative researchers see cases as to

meaningful but complex configurations of events and th

structures (e.g., guerilla movements), and their cases OJ

that is presumed to be at the researcher's disposal.

elare typically macrolevel. Furthermore, they treat cases as singular, whole entities purposefully defined and a:

selected, not as homogeneous observations drawn at a

random from a pool of equally plausible selections. d Most comparative studies start with the seemingly e simple idea that social phenomena in like settings (such a as organizations, countries, regions, cultures, etc.) may parallel each other sufficiently to permit comparing and contrasting them. The clause, "may parallel each

)n. other sufficiently," is a very important part of this ra­ fonnulation. The comparative researcher's specifica­:he tion of relevant cases at the start of an investigation is :he really nothing more than a working hypothesis that the lId cases initially selected are in fact instances of the same nts thing (e.g., guerilla movements) and are.alike enough ips to pennit comparison. In the course of the research, .gn the investigator may decide otherwise and drop some :). cases or even whole categories of cases because they the do not appear to belong with what seem to be the core :ek cases. Sometimes, this process of sifting through the :ral cases leads to an enlargement of the set of relevant '01- cases and a commensurate broadening of the scope of not the guiding concepts (e.g., from guerilla movements 71, to radical opposition movements) or to the develop­ing ment of a typology of cases (e.g., types of guerilla of movements).

;at­ Usually, this sifting and sorting ofcases is carried on )ne in conjunction with concept fonnation and elaboration . in (Walton, 1992). Concepts are revised and refined as fhe the boundary of the set of relevant cases is shifted

in and clarified (Ragin, 1994). Important theoretical dis­of tinctions often emerge from this dialogue of ideas and

rch evidence. The researcher's answers to both "What are my cases?" and "What are these cases of?" may change throughout the course of the research, as the investi­gator learns more about the phenomenon in question and refines his or her guiding concepts and analytic schemes.

do­.ses

NOF CASES vey eo­ Onekey lesson in every course in quantitative social '.g., research is that "more cases is better." More is better key in two main ways. First, researchers must meet a tive threshold number of cases to even apply quantitative ons· methods, usually cited as an N of 30 to 50. Second,

the smaller the N, the more the data must conform ; as to the assumptions of statistical methods, for example, and the assumption that variables are nonnally distributed

or the assumption that subgroup variances are roughly equal. However, small N s almost guarantee that such assumptions will not be met, especially when the cases are macrolevel. This textbook bias toward large N s dovetails with the implicit assumption that cases are empirically given, not constructed by the researcher, and that they are abundant. The only problem, in this light, is whether the researcher is willing and able to gather data on as many cases as possible, preferably hundreds if not thousands.

Comparative Method 149

By contrast, comparative research is very often defined by its focus on phenomena that are of inter­est because they are rare-that is, precisely because the N of cases is small. Typically, these phenomena are large scale and historically delimited, not generic in any sense. The population of cases relevant to an investigation is often limited by the historical record to a mere handful. The key contrast with textbook social science derives from the simple fact that many phenom­ena of interest to social scientists and their audiences are historically or culturally significant. To argue that social scientists should study only cases that are generic and abundant or that can be studied in isolation from their historical and cultural contexts would severely limit both the range and value of social science.

THEORY TESTING

Conventional presentations of social science methodology place great emphasis on theory testing. In fact, its theory-testing orientation is often presented as what makes social science scientific. Researchers are advised to follow the scientific method and develop their hypotheses in isolation from the analysis ofempir­ical evidence. It is assumed further that existing theory is sufficiently well fonnulated to pennit the specifi­cation of testable hypotheses and that social scientific knowledge.advances primarily through the rejection of theoretical ideas that consistently fail to find empirical support. Of course, the textbook view does not bar from social science those ideas that are generated in a more inductive manner, but any such idea is treated as suspect until it is subjected to an explicit test, using data that are different from those used to generate the idea.

It is without question that theory plays a central role in social research and that, in fact, almost all social research is heavily dependent on theory in some way. However, it is usually not possible to apply the theory­testing paradigm in small-N, case-oriented research. Most comparative research has a very strong inductive component. Researchers typically focus on a small number of cases and may spend many years learn­ing about them, increasing their depth of knowledge. Countless ideas and hypotheses are generated in this process of learning about cases, and even the very definition of the population (What are these cases of?) may change many times in the course of the investi­gation. Furthennore, because the number of relevant cases in comparative research is usually very small

150 comparative Method

and limited by the historical record, it is simply not possible to test an idea generated through in-depth study using "another sample" of cases. Very often, the cases included at the outset of an investigation comprise the entire universe of relevant cases.

The immediate objective of most comparative research is to explain the "how" of historically or cul­turally significant phenomena-for example, How do guerilla movements form? Theory plays an important orienting function by providing important leads and guiding concepts for empirical research, but exist­ing theory is rarely well formulated enough to pro­vide explicit hypotheses in comparative research. The primary scientific objective of comparative research is not theory testing, per se, but concept formation, elaboration, and refinement. In comparative research, the bulk of the research effort is often directed toward constituting the cases in the investigation and sharp­ening the concepts appropriate for the cases selected (Ragin & Becker, 1992).

THE DEPENDENT VARIABLE

One of the most fundamental notions in textbook presentations of social research is the idea of the variable-a trait or aspect that varies from one case to the next-and the associated idea of looking for patterns in how variables are related across cases. For example, do richer countries experience less politi­cal turmoil than poorer countries? If so, then social scientists might want to claim that variation in political turmoil across countries (the dependent or outcome variable) is explained in part by variation in country wealth (the independent or causal variable). Implicit in these notions about variables is the principle that the phenomena that social scientists wish to explain must vary across the cases they study; otherwise, there is nothing to explain. It follows that researchers who study outcomes that vary little from one case to the next have little hope of identifying the causes of those outcomes.

Comparative researchers, however, often intention­ally select cases that do not differ from each other with respect to the outcome under investigation. For example, a researcher might attempt to explain how guerilla movements come about and study instances of their successful formation. From the viewpoint of textbook social research, however, this investigator has committed a grave mistake-selecting cases that vary only slightly, if at all, on the dependent variable. After

all, the cases are all instances of successfully formed guerilla movements. Without a dependent variable that varies, this study seems to lack even the possibility of analysis.

These misgivings about studying instances of "the same thing" are well reasoned. However, they are based on a misunderstanding of the logic of com­parative research. Rather than using variation in one variable to explain variation in another, compara­tive researchers often look for causal conditions that CAL are common across their cases-that is, across all

Tinstances of the outcome (see Robinson, 1951). For dataexample, if all cases of successfully formed guerilla logi,movements occur in countries with both high levels of tiveagrarian inequality and heavy involvement in export of \agriculture, then these structural factors might be pIe,important to the explanation of guerilla movements. theIn fact, the very first step in the comparative study instof successfully formed guerilla movements, after con­imastituting the category and specifying the relevant witlcases, would be to identify causal conditions that

are common across instances. Although using con­ con tiOI1stants to account for constants (i.e., searching for relacausal commonalities shared by similar instances) is we!common in comparative research, it is foreign to tech­

niques that focus on relationships among variables--on var

causal conditions and outcomes that vary substantially at ( across cases.

Sometimes, it is possible for comparative researchers cau queto identify relevant negative cases to compare with

positive cases. For example, guerilla movements that cor thafailed early on might be used as negative cases in a

study of successfully established guerilla movements. stu delNegative cases are essential when the goal is to iden­dittify the sufficient conditions for an outcome (Ragin, gel2000). For example, ifa comparative researcher argues ferthat a specific combination of causal conditions is suf­Afficient for the successful establishment of a guerilla

movement, it is important to demonstrate that these an

conditions were not met in the near misses (i.e., in mt

relevant negative cases). Note, however, that it is as thlpossible to assess the sufficiency of a set of causal atlconditions only if the researcher is able to consti­E!tute the set of relevant negative cases. Often, it is

very difficult to do so, either because the empirical ce

category is too broad or vague (e.g., the category ar

"absence of a successful guerilla movement") or the ca thevidence is impossible to locate or collect (e.g., data

on aborted movements). When these obstacles can in

be overcome, it is important to understand that the

c

151

constitution and analysis of the positive cases is a necessary preliminary for the constitution and analysis of negative cases (see also Griffin et ai., 1997). Thus, even when a comparative researcher plans to look at an outcome that varies across cases (i.e., present in some and absent in others), it is often necessary first to study cases that all have the outcome (i.e., the positive cases).

CAUSAL ANALYSIS The main goal of most analyses of social

data, according to textbook presentations of the logic of social research, is to assess the rela­tive importance of independent variables as causes of variation in the dependent variable. For exam­ple, a researcher might want to know which has the· greater impact on the longevity of democratic institutions, their design or their perceived legit­imacy. In this view, causal variables compete with each other to explain variation in an out­come variable. A good contender in this competi­tion is an independent variable that is strongly cor­related with the dependent variable but has only weak correlations with its competing independent variables.

Comparative researchers, by contrast, usually look at causes in terms of combinations: How did relevant

s causes combine in each case to produce the outcome in question? Rather than viewing causes as competitors, comparative researchers view them as raw ingredients that combine to produce the qualitative outcomes they study. The effect of any particular causal condition depends on the presence and absence of other con­ditions, and several different conditions may satisfy a

s general causal requirement-that is, two or more dif­ferent causes may be equivalent at a more abstract level.

a After constituting and selecting relevant instances of e an outcome (e.g., successfully formed guerilla move­n ments) and, ifpossible, defining relevant negative cases lS as well, the comparative investigator's task is to address 11 the causal forces behind each instance, with special i­ attention to similarities and differences across cases. is Each case is examined in detail, using theoretical con­al cepts, substantive know ledge, and interests as guides to

~ answer "how" the outcome came about in each positive Ie case and why it did not in the negative cases (assuming ta they can be confidently identified). A common finding ill in comparative research is that different combinations he

comparative Method

ofcauses may produce the same outcome (Ragin, 1987; see also Mackie, 1974).

SUMMARY The contrasts sketched in this entry present a

bare outline of the distinctive features of comparative research, from the constitution ofcases to the examina­tion of the different combinations of conditions linked to an outcome across a set of cases. The key point is that comparative research does not conform well to textbook admonitions regarding the proper conduct of social research. Social scientists and their audiences are often interested in understanding social phenomena that are culturally or historically significant in some way. Of necessity, these phenomena are often rare and can be understood only through in-depth, case-oriented research.

-Charles C. Ragin

See also CASE STUDY

REFERENCES Eckstein, H. (1975). Case study and theory in political science.

In F. 1. Greenstein & N. W. Polsby (Eds.), Handbook of political science: Vol. 7. Strategies of inquiry (pp. 79-137). Reading, MA: Addison-Wesley.

Griffin, L., Caplinger, C., Lively, K., Malcom, N. L., McDaniel, D., & Nelsen, C. (1997). Comparative-historical analysis and scientific inference: Disfranchisement in the U.S. South as a test case. Historical Methods, 30, 13-27.

Mackie, J. L. (1974). The cement of the universe: A study of causation. Oxford, UK: Oxford University Press.

Ragin, C. C. (1987). The comparative method: Moving beyond qualitative and quantitative strategies. Berkeley: University of California Press.

Ragin, C. C. (1994). Constructing social research. Thousand Oaks, CA: Pine Forge Press.

Ragin, C. C. (2000). Fuzzy-set social science. Chicago: University of Chicago Press.

Ragin, C. c., & Becker, H. S. (1992). What is a case? Exploring the foundations of social inquiry. New York: Cambridge University Press.

Robinson, W. S. (1951). The logical structure of analytic induction. American Sociological Review, 16, 812-818.

von Wright, G. H. (1971). Explanation and understanding. Ithaca, NY: Cornell University Press.

Walton, 1. (1992). Making the theoretical case. In C. C. Ragin & H. S. Becker (Eds.), What is a case? Exploring thefounda­tionsof social inquiry (pp. 121-137). New York: Cambridge University Press.

152 comparative Research

COMPARATIVE RESEARCH

The major aim of comparative research is to identify similarities and differences between social entities.

Comparative research seeks to compare and contrast nations, cultures, societies, and institutions. Scholars differ on their use of the terminology: To some, comparative research is strictly limited to comparing two or more nations (also known as "cross-national research"), but other scholars prefer to widen the scope to include comparison of many different types of social and/or cultural entities. Yet other scholars use the term to encompass comparisons of subcultures or other social substrata either within or across nation-states or other cultural and social boundaries.

Although scholars are far from a consensus on a definition, the trend appears to be toward defining comparative research in the social sciences as research that compares systematically two or more societies, cultures, or nations. In actual implementation, com­parisons of nations prevail as the dominant practice. The intent of comparative research is more univer­sal: Comparative research aims to develop concepts and generalizations based on identified similarities and differences among the social entities being compared, especially in their characteristic ways of thinking and acting; in their characteristic attitudes, values, and ideologies; and in the intrinsic elements of their social structures. This then serves as a means of enhanc­ing one's understanding and awareness of other social entities.

HISTORICAL DEVELOPMENT

Sociology's founding fathers were all comparative researchers. Karl Marx, Max Weber, Emile Durkheim, and Alexis de Tocqueville, to name just a few, all firmly committed themselves to the comparative method, whether they studied roles, institutions, societies, nations, cultures, groups, or organizations. Durkheim, for example, sought to find a general "law" that would explain national and occupational suicide rate varia­tions. In the early 20th century, though, comparative research waned because its methodological resources were deemed insufficiently rigorous during a time when scholars were insisting that social research con­form to greater and greater levels of methodological precision. However, since World War II, comparative

research has once again assumed its pivotal position

in social science research, due in part to improved methodologies and methodological tools and in part corr to the international climate that emerged after World expl War II. That climate (the once polarized communist whi and noncommunist worlds, for example) and our ensu­ diffi ing internationalization have both contributed to the the significant reemergence of comparative social science imp research. in (

ask sayAPPLICATION sist,

The purposes of comparative research are many, but the one key task is to support and contribute to theory con formation. Although theoretical frameworks drive the can construction of comparative research endeavors, the ver results of such research often drive theory reforma­ in tion. Another key task is to support policy making, In 1 principally at the national level. Can Country B use bet the strategic policies of Country A in coping with a of' given social problem (drug abuse, for example)? Or are there unique differences between the two countries sigthat render such a strategy impractical? Yet another abi purpose ofcomparative research is to ascertain whether sec the same dimension of a given concept (e.g., religious ha' commi tment) can be used as a common social indicator. sar Does a given concept generalize to all nations (or other del social entities)? am

Comparative research is all about perspective. res Researchers in one nation need a means to adopt and to understand the perspectives of their counterparts in reI other nations. As the world becomes ever more glob­alized, the need for such understanding should be ill( clear: National policies need to consider and encom­ So pass the needs of the global partners in any way affected (siby policy implementation. Do policymakers have the St' necessary perspective to ensure such cooperation and Pr compliance? ge

Comparative social science research is implemented na under a variety of methodologies, ranging from strictly be qualitative to rigorously quantitative. Case studies and IS similar kinds of analyses typify the descriptive qualita­

0\ tive approach, which can be conducted by researchers who are members of the social entities being studied p, or by researchers from outside the social entities being

c~

examined. The quantitative approaches to comparative b( research have assumed a more dominant position in OJ recent years as the tools (especially computational, fl(

statistical, and mathematical) have become available re to deal with the many methodological complexities of bl rigorous comparative research.