Political Behavior, Vol. 27, No. 4, December 2005 ( Ó 2005)
DOI: 10.1007/s11109-005-7408-4
In replying to Mondak and Sanders, I introduce the notion of ‘‘Kelvinist tolerance,’’ or an absolute absence of any intolerance whatsoever. I contend that while we can imagine such an extreme level of tolerence, in our empirical world it occurs about as frequently as the absolute zero of the Kelvin scale of temperature. Consequently, I reject the assertion of Mondak and Sanders that special statistical approaches are essential for analyzing tolerance, arguing instead in favor of parsimony in both conceptualization and analytical strategies.
Key words: political tolerance; absolute tolerance; measurement error.
I should begin my reply to Mondak and Sanders with a note of appreciation for both the style and substance of their reactions to my comments.
The issues we are debating are serious intellectual ones, and they are worthy of the careful and considered arguments of scholars adopting alternative views on the nature of intolerance. I respect their viewpoint, even while disagreeing with it, and it is obvious that they feel precisely the same.
After carefully considering the Mondak and Sanders argument, I conclude that we still differ considerably on the three crucial matters: the conceptualization of the tolerance—intolerance continuum, issues of operationalizing the concept and especially measurement error, and the preferred analytical strategy for tolerance data. While hoping to avoid too much redundancy, I will mainly focus on our unresolved differences in this reply.
James L. Gibson, Sidney W. Souers Professor of Government, Department of Political Science,
Washington University in St. Louis, Campus Box 1063, 219 Eliot Hall, St. Louis, MO 63130-4899,
United States. (jgibson@wustl.edu); Fellow, Centre for Comparative and International Politics,
Stellenbosch University, South Africa.
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0190-9320/05/1200-0339/0 Ó 2005 Springer Science þ Business Media, Inc.

340 GIBSON
KELVINIST TOLERANCE?
Natural scientists differ in the metrics they find useful for measuring temperature. Some scientists find the Kelvin scale most useful because they require a continuum calibrated at the extreme by an absolute zero—the complete cessation of the movement of molecules—using a ratio-level scale.
Other scholars are satisfied with interval-level measurement and therefore find the Fahrenheit or Celsius scale useful. Which scale one uses depends a great deal upon the research objective, and the nature of the reality one is studying.
Mondak and Sanders assert that: ‘‘Political tolerance constitutes a willingness to extend the full rights of citizenship to all others without exception.’’
Thus, they seem to require a ratio-level scale for measuring tolerance. I define tolerance as the degree of willingness to extend a variety of rights of citizenship to ideas that differ to some degree from mainstream political thought in a given context. Thus, tolerance should be calibrated by the breadth of ideas deemed worthy of some form of expression, as well as by the specific activity by which the ideas are advocated. Consequently, an interval-level measure is sufficient for my purposes.
I can imagine that some people would allow all ideas to be expressed in every conceivable legal way,
1 but these people are as rare as the absolute zero of the Kelvin scale. My suspicion is that there are very few people in the world who would not support repressing some sort of pure speech (i.e., words without action), be it hate speech, sedition, libel, advocacy of illegal and/or revolutionary activity, support for suicide bombing and other forms of terrorism, etc. Should a tenured university professor in Colorado be fired for making derogatory remarks about the victims of the 9/11 attack on the
United States? Should a person in New Hampshire be allowed to call a police officer a ‘‘goddam racketeer?’’ Should a Floridian be allowed to praise publicly suicide bombers? Should so-called hate speech be banned on university campuses in the United States? And this is just speech. Once more extreme activities are included (e.g., so-called symbolic speech), the size of the category ‘‘tolerant without exception’’ undoubtedly shrinks to practically zero. Should an admitted Communist be allowed to burn the American flag? Should one be allowed to wear in public places a jacket with the slogan ‘‘Fuck the Draft’’ printed on the back? Or to make financial contributions to organizations that do not believe that Israel has a legitimate right to exist? These are the hard questions of civil liberties today. I daresay that were a sample of Americans asked this entire set of questions the number of tolerance Kelvinists would round off to zero. So, my basic contention is that Mondak and Sanders are making a distinction without a difference by advocating their conceptualization of tolerance as a ratio-level scale.
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PARSIMONY IN THE STUDY OF TOLERANCE AND INTOLERANCE 341
In principle, all concepts in political science could be thought of as having an absolute zero point. One might be absolutely liberal, absolutely individualistic, absolutely authoritarian, by which I mean there are no contexts in which other values or circumstances generate exceptions to the extreme rule. That we can imagine these absolute positions does not mean they are useful.
How widespread is the conceptualization of tolerance and intolerance as a ratio-level scale? Mondak and Sanders cite a number of definitions proffered by scholars, including one Dick Bingham and I expressed in 1982.
I cannot speak to what other authors may have meant when they wrote their definitions of tolerance. But what Bingham and I meant is not that
‘‘political tolerance refers to a [dichotomous] willingness to extend the rights of citizenship’’ but rather that ‘‘political tolerance refers to [the degree of] willingness to extend the rights of citizenship.’’ My central point here is that, while some may recognize an absolute zero of tolerance, the utility of doing so approximates the utility of Kelvin’s absolute zero to meteorologists.
EMPIRICAL IMPLICATIONS
Mondak and Sanders conclude that those with a score of zero on the
15-point GSS index are different from those with a score greater than zero.
Allow me for the sake of argument to concede that they are different. The question to ask is: Why are they different? Mondak and Sanders want to treat these people as tolerance Kelvinists, but there are alternative explanations for why they receive a zero on the GSS index. After all, the statistical test only indicates to us (at best
3
) that these folks are different.
It may well be that the test is correct, but that these folks are different because they belong to a category of respondents for which measurement error is particularly high. By that I specifically mean these are people for whom their observed scores (zero) differ substantially from their true scores. Even more specifically, this means that people with varying true scores are assigned the identical observed score (zero). Mondak and
Sanders must admit that a score of zero includes two types of people: tolerance Kelvinists and people for whom the correct questions were not asked.
This is a classic case of measurement error, and the error is systematic, not random. Moreover, it is a type of measurement error that also infects those with a score of 15. Presumably, some of those with an observed score of 15 are truly 15s; but some are far more extreme than 15s; there is no telling whether there any limits to what they would do to groups/ideas/ actions they despise. That they all receive the same observed score is a problem of measurement error. How great an effect this measurement error has in any given analysis cannot be deduced or prejudged.

342 GIBSON
As an empirical matter, Mondak and Sanders make the crucial mistake of being willing to assume that those who are tolerant on the fifteen, relatively easy GSS items would remain tolerant when asked more demanding questions. I have already demonstrated empirically that in both the Russian and
American samples most respondents do not sustain their tolerance when asked additional questions. So Mondak and Sanders were wrong to consider the 18% of the GSS sample as consisting of tolerance Kelvinists.
Moreover, I even believe that I would be wrong to treat the 4–5% of the
GSS sample as tolerance Kelvinists. The only basis on which these people can be assumed to be absolutely tolerant is to make assumptions about how they would answer questions that they were not asked. In analyzing survey data, I always have difficulty understanding what respondents actually mean when they answer the questions I ask. To guess about what they might mean in relation to questions I did not ask is not something I feel competent, or compelled, to do.
Thus, to assume that the true tolerance score of those who receive a zero on the GSS scale is zero is not justified. Those scored at zero are heterogeneous (both by logic and by my empirical evidence). What is distinctive about those who receive a zero on the scale is that measurement error is much more common than error for other scores on the index. Much of the analysis of Mondak and Sanders relies heavily not on empirical matters but on their assumption about what people might say in reply to questions not asked on the survey.
THE MEANING AND UTILITY OF TWO-STAGE ANALYSIS
Perhaps the main point to be taken from the Mondak and Sanders analysis has nothing at all to do with substance and conceptualization but much to do with ordinary psychometrics. When the distribution of a scale deviates from normality, certain statistical consequences flow. I agree that under some circumstances, statistical adjustments might need to be made. It is unclear to me, however, why any given approach should be privileged over another, especially if we jettison the theoretical position that tolerance should be thought of as absolute.
For instance, why not treat those with a score of zero on the 15-point scale as equivalent to respondents with missing data, and then turn the problem into one of data imputation for this portion of the sample? Perhaps the problem is that distributional oddities generate curvilinear effects that are not well indexed by a Pearson correlation coefficient and other statistics assuming linearity. If so, then a transformation of the index might be desirable. If this is simply a problem of some observations having more measurement error than others, then weighted least squares may be the solution, or perhaps other approaches to dealing with heteroscadasticity would be useful.

PARSIMONY IN THE STUDY OF TOLERANCE AND INTOLERANCE 343
Mondak and Sanders claim that two processes are at work in our indicators of tolerance. Why not go further and consider the possibility that n-processes are at work in the data, and that therefore the number of possible solutions to the distributional problems is rather large (as it always is with distributional problems). It should be clear that it is Mondak and Sanders who impose a theoretical interpretation on the data, not the data themselves.
Consider the data they report in Table 1. First, since there are 863 cases being analyzed, I will only focus on effects significant at p < .001. From the
‘‘All Zero’’ equation we learn that two factors differentiate those who are
‘‘tolerant’’ versus those who are ‘‘intolerant:’’ support for general democratic norms and support for democratic procedures. Those who express more support for general democratic norms and more support for democratic procedures are more likely to be tolerant, and both variables of course have an independent influence on tolerance.
An alternative explanation of these variables is simply that these coefficients indicate the distinctiveness of a subgroup of respondents who range from relatively tolerant to quite tolerant even though they all receive exactly the same observed score. These coefficients single out this portion of the respondents because they are distinctive in their relatively high, but not necessarily absolute tolerance.
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Finally, note that the substantive conclusions on the three analyses reported in Table 1 of Mondak and Sanders are as follows: (1) those more supportive of democratic values are more likely to be tolerant Kelvinist, (2) they are also less likely to be intolerant, and (3) these conclusions are entirely compatible with and add little to the linear effect described in equation one.
Finally, it should also be clear—and Mondak and Sanders are indeed clear on this point—that their methodological critique is not general but is instead limited to the GSS measures of political tolerance. The flaws in the
GSS measures are numerous. The responses are collected on a dichotomous response set so intensity is not measured; no effort is made to qualify the group stimuli as disliked; the activity stimuli are tepid since the really hard actions of civil liberties are far from represented in the simple GSS statements; and indices based on the items are subject to enhanced measurement error at the two extremes. None of these liabilities is of necessity applicable to tolerance measures based on the least-liked technique. So the
Mondak and Sanders critique of multidimensionality must, at best, be confined to the GSS indicators, and the American context. Whereas
Mondak and Sanders developed a conceptualization to fit the flawed GSS data, Sullivan, Piereson, and Marcus created an operationalization to fit their conceptualization. The difference between the two approaches should not be underestimated, and whatever remains of the Mondak and Sanders argument should not be routinely applied to the Sullivan, Piereson, and
Marcus indicators.

344 GIBSON
CONCLUDING COMMENTS
Mondak and Sanders are free to conceptualize tolerance in any way they wish. What concerns me, however, is that they go further to address the empirical implications of their conceptualization, and even go so far as to advocate some methodological desiderata for those who analyze tolerance scales in the future. Indeed, part of my motivation for entering this debate and publishing a challenge to Mondak and Sanders is that I fear that some future reviewer or editor will take seriously the Mondak and Sanders position that zero-inflated negative binomial analysis is the preferred (if not required) method for analyzing tolerance data. In my view, it is not.
In many areas of political science, I wonder if the canon of parsimony has become less and less vaunted. I am all in favor of nonlinear, conditional relationships, multidimensional concepts, and advanced statistical techniques when they provide benefit. But I also strongly subscribe to the canon of parsimony: In order to move beyond simple explanations (and linearity) there must be clear and persuasive reasons for doing so. Mondak and Sanders want to use a two-stage technique on tolerance data. Can this be done?
Without a doubt. Is there utility to doing so? Perhaps not. Is it useful to conceptualize Kelvinist tolerance? In the same sense that some might care to speculate about the number of angels who can dance on the head of a pin, Kelvinist tolerance might be an interesting concept. But for those doing empirical research on political tolerance throughout the world neither Kelvinist tolerance nor zero-inflated negative binomial models are likely to be of much utility. Good survey researchers of course care about the distributional properties of indicators, just as they must be extremely reticent about ascribing answers to respondents to questions they are not asked. Mondak and Sanders have certainly provided a service by stimulating us to think clearly and carefully about the meaning of tolerance and intolerance. But in the end, their challenge to the conventional wisdom in the field should only make us reassured that the conventional wisdom is wise and should remain conventional.
Acknowledgments.
I would like to acknowledge the most helpful comments of the editors on an earlier version of this article.
NOTES
1. Mondak and Sanders place considerable emphasis on whether or not an action is legal within a particular context. While not wishing to extend this debate too far into normative terrain, legality is not a determining factor for me. In the early days of the American republic, it was illegal to criticize the president according to the Alien and Sedition Act. Criticism of a president is an essential element of the political contestation necessary to democracy, and

PARSIMONY IN THE STUDY OF TOLERANCE AND INTOLERANCE 345 therefore my position is that a democratic society must tolerate such activity, whatever the current law. From the point-of-view of democratic theory, I find footnote 3 in the Mondak and Sanders article even more worrisome than their central argument that tolerance is a dichotomy.
2. And I should note that there are good reasons why we do not ask these questions in our surveys. Most survey researchers are interested, as some point or another, in individual differences. Questions that are as extreme as those I mention above are not useful because they fail to differentiate people. Consequently, one rarely sees such items asked in contemporary surveys.
3. It is unclear to me that a chi-square test that is statistically significant at p < .001 with over
800 cases points to anything of substantive significance.
4. I reiterate that this argument pertains to virtually all of the indicators commonly used by political scientists. Those who rate themselves as ‘‘extremely conservative’’ vary in their degree of conservatism; few if any should be thought of as Kelvinist conservatives; and we should not make assumptions about how these folks would answer questions they were not asked.