Comments on "Christian nationalism: A stained-glass ceiling for LGBT candidates?"

1.

Politics, Groups, and Identities recently published Cravens 2022 "Christian nationalism: A stained-glass ceiling for LGBT candidates?". The key predictor is a Christian nationalism index that ranges from 0 to 1, with a key result that:

In both cases, a one-point increase in the Christian nationalism index is associated with about a 40 percent decrease in support for both lesbian/gay and transgender candidates in this study.

But the 40 percent estimates are based on Christian nationalism coefficients in models in which Christian nationalism is interacted with partisanship, race, and religion, and I don't think that these coefficients can be interpreted as associations across the sample. The estimates across the sample should be from models in which Christian nationalism is not included in an interaction, of -0.167 for lesbian and gay political candidates and -0.216 for transgender political candidates. So about half of 40 percent.

Check Cravens 2022 Figure 2, which reports results for support for lesbian and gay candidates: eyeballing from the figure, the drop across the range of Christian nationalism is about 14 percent for Whites, about 18 percent for Blacks, about 9 percent for AAPI, and about 15 percent for persons of another race. No matter how you weight these four categories, the weighted average doesn't get close to 40 percent.

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2.

And I think that the constitutive terms in the interactions are not always correctly described, either. From Cravens 2022:

As the figure shows, Christian nationalism is negatively associated with support for lesbian and gay candidates across all partisan identities in the sample. Christian nationalist Democrats and Independents are more supportive than Christian nationalist Republicans by about 23 and 17 percent, respectively, but the effects of Christian nationalism on support for lesbian and gay candidates are statistically indistinguishable between Republicans and third-party identifiers.

Table 2 coefficients are 0.231 for Democrats and 0.170 for Independents, with Republicans as the omitted category, with these partisan predictors interacted with Christian nationalism. But I don't think that these coefficients indicate the difference between Christian nationalist Democrats/Independents and Christian nationalist Republicans. In Figure 1, Christian nationalist Democrats are at about 0.90 and Christian nationalist Republicans are at about 0.74, which is less than a 0.231 gap.

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3.

From Cravens 2022:

Christian nationalism is associated with opposition to LGBT candidates even among the most politically supportive groups (i.e., Democrats).

For support for lesbian and gay candidates and support for transgender candidates, the Democrat predictor interacted with Christian nationalism has a p-value less than p=0.05. But that doesn't indicate whether there is sufficient evidence that the slope for Christian nationalism is non-zero among Democrats. In Figure 1, for example, the point estimate for Democrats at the lowest level of Christian nationalism looks to be within the 95% confidence interval for Democrats at the highest level of Christian nationalism.

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4.

From Cravens 2022:

In other words, a one-point increase in the Christian nationalism index is associated with a 40 percent decrease in support for lesbian and gay candidates. For comparison, an ideologically very progressive respondent is only about four percent more likely to support a lesbian or gay candidate than an ideologically moderate respondent; while, a one-unit increase in church attendance is only associated with a one percent decrease in support for lesbian and gay candidates. Compared to every other measure, Christian nationalism is associated with the largest and most negative change in support for lesbian and gay candidates.

The Christian nationalism index ranges from 0 to 1, so the one-point increase discussed in the passage is the full estimated effect of Christian nationalism. The church attendance predictor runs from 0 to 6, so the one-unit increase in church attendance discussed in the passage is one-sixth the estimated effect of church attendance. The estimated effect of Christian nationalism is still larger than the estimated effect of church attendance when both predictors are put on a 0-to-1 scale, but I don't know of a good reason to compare a one-unit increase on the 0-to-1 Christian nationalism predictor to a one-unit increase on the 0-to-6 church attendance predictor.

The other problem is that the Christian nationalism index combines three five-point items, so it might be a better measure of Christian nationalism than, say, the progressive predictor is a measure of political ideology. This matters because, all else equal, poorer measures of a concept are biased toward zero. Or maybe the ends of the Christian nationalism index represent more distance than the ends of the political ideology measure. Or maybe not. But I think that it's a good idea to discuss these concerns when comparing predictors to each other.

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5.

Returning to the estimates for Christian nationalism, I'm not even sure that -0.167 for lesbian and gay political candidates and -0.216 for transgender political candidates are good estimates. For one thing, these estimates are extrapolations from linear regression lines, instead of comparisons of observed outcomes at low and high levels of Christian nationalism, so it's not clear whether the linear regression line is correctly estimating the outcome for high levels of Christian nationalism, given that, for each Christian nationalist statement, the majority of the sample falls on the side of the items opposing the statement, so that the estimated effect of Christian nationalism might be more influenced by opponents of Christian nationalism than by supporters of Christian nationalism.

For another thing, I think that the effect of Christian nationalism should be conceptualized as being caused by a change from indifference to Christian nationalism to support for Christian nationalism, which means that including observations from opponents of Christian nationalism might bias the estimated effect of Christian nationalism.

For an analogy, imagine that we are interested in the effect of being a fan of the Beatles. I think that it would be preferable to compare, net of controls, outcomes for fans of the Beatles to outcomes for people indifferent to the Beatles, instead of comparing, net of controls, outcomes for fans of the Beatles to outcomes for people who hate the Beatles. The fan/hate comparison means that the estimated effect of being a fan of the Beatles is *necessarily* the exact same size as the estimated effect of hating the Beatles, but I think that these are different phenomena. Similarly, I think that supporting Christian nationalism is a different phenomenon than opposing Christian nationalism.

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NOTES

1. Cravens 2022 model 2 regressions in Tables 2 and 3 include controls plus a predictor for Christian nationalism, three partisanship categories plus Republican as the omitted category, three categories of race plus White as the omitted category, and five categories of religion plus Protestant as the omitted category, and interactions of Christian nationalism with the three included partisanship categories, interactions of Christian nationalism with the three included race categories, and interactions of Christian nationalism with the five included religion categories.

It might be tempting to interpret the Christian nationalism coefficient in these regressions as indicating the association of Christian nationalism with the outcome net of controls among the omitted interactions category of White Protestant Republicans, but I don't think that's correct because of the absence of higher-order interactions. Let me discuss a simplified simulation to illustrate this.

The simulation had participants that were either male (male=1) or female (male=0) and participants that were either Republican (gop=1) or Democrat (gop=0). In the simulation, I set the association of a predictor X with the outcome Y to be -1 among female Democrats, to be -3 among male Democrats, to be -6 among female Republicans, and to be -20 among male Republicans. So the association of X with the outcome was negative for all four combinations of gender and partisanship. But the coefficient on X was +2 in a linear regression with predictors only for X, the gender predictor, the partisanship predictor, an interaction of X and the gender predictor, and an interaction of X and the partisanship predictor.

Simulation for the code in Stata and in R.

2. Cravens 2022 indicated about Table 2 that "Model 2 is estimated with three interaction terms". But I'm not sure that's correct, given the interaction coefficients in the table and given that the Figure 1 slopes for Republican, Democrat, Independent, and Something Else are all negative and differ from each other and the Other Christian slope in Figure 3 is positive, which presumably means that there were more than three interaction terms.

3. Appendix C has data that I suspect is incorrectly labeled: 98 percent of atheists agreed or strongly agreed that "The federal government should declare the United States a Christian nation", 94 percent of atheists agreed or strongly agreed that "The federal government should advocate Christian values", and 94 percent of atheists agreed or strongly agreed that "The success of the United States is part of God's plan".

4. I guess that it's not an error per se, but Appendix 2 reports means and standard deviations for nominal variables such as race and party identification, even though these means and standard deviations depend on how the nominal categories are numbered. For example, party identification has a standard deviation of 0.781 when coded from 1 to 4 for Republican, Democrat, Independent, and Other, but the standard deviation would presumably change if the numbers were swapped for Democrat and Republican, and, as far as I can tell, there is no reason to prefer the order of Republican, Democrat, Independent, and Other.