(This is cross-posted from ProgressiveFix.com, the new online face of the Progressive Policy Institute, where I will be posting regularly.  Give 'em a look.)

To read the first part of this post, click here.

Defining the Center

Let’s examine Hacker and Pierson’s definition of “the center.” When they compare activists to independents, changes in the distance from independents may be due to growing extremism among activists. However, the distance may grow without activists changing their views at all if independents change their views. So saying Republican activists drifted further away from the center than Democratic activists may misstate what occurred; independents may simply have drifted toward Democratic activists over time without activists drifting anywhere. It’s also possible that Republican activists have grown more extreme, which has pushed independents closer to Democratic activists’ (unchanged) views.

Furthermore, secular changes in ideology over time can move people from the independent category into Democratic and Republican camps and vice versa, making it difficult to say whether the changes identified indicate that activists (or independents) are changing their views, or that it’s just flows into or out of the parties that is changing. If one of the parties looks more or less extreme, it could simply be that people who would have called themselves independent in the past are now identifying with one of the parties, making the leftover independents look somewhat more extreme in the opposite direction.

Rather than compare activists to independents, why not simply measure how far they are from the midpoint of the ideology scale? When one does so, one obtains the graph below.

By this measure, which avoids all of the problems with using independents as a reference point, the change in extremism among Democratic activists looks exactly the same as the trend for Republican activists. Once again, Republican activists look more extreme in any year, and this time (not shown) this remains the case when one looks at the unsmoothed data points.

A Better Way to Measure Ideology

There is also a problem with Hacker and Pierson’s measure of ideology. If we want to know whether party activists have become ideologically more extreme over time, we should use as pure a measure of ideology as possible. The measure Hacker and Pierson use, however, conflates ideology with tolerance and empathy because it is based on questions asking how warm or cold one feels toward liberals and conservatives. It could be that Democratic activists are simply more tolerant of their opponents than Republican activists rather than being more centrist. One can feel warmly toward a group without identifying oneself with it.

A better measure of changing ideology among party activists would be to look directly at changes in self-identified ideology. The NES asks respondents to place themselves on a 7-point scale ranging from extremely liberal to extremely conservative. Here, then, is a final chart showing trends for activists in each party, with ideology measured as the distance of activists from “4” – the midpoint of the seven-point scale. The actual data points are connected and the smoothed trends are shown as black dashed lines. It should be noted that this chart is based on even smaller sample sizes than Hacker and Pierson’s, so I show the margin of error for the data points as dashed vertical lines. I also omit off-year elections to make the chart less noisy.

This chart confirms that Republican activists more often than not have been more extreme than Democratic activists, though the two groups were statistically tied in 1972, 1976, 1992, and 2004. There is a clear trend toward greater extremism among Republican activists. Among Democratic activists, there was little consistency between 1972 and 1998, but they appear to have moved to the center in 2000 and 2002 before jumping up to the level of Republican extremism in 2004.

Finally, there is the claim by Hacker and Pierson that Democratic activists are more centrist than other Democrats. In my results, this was not true in 2004 whether one used the thermometer index or the self-identified seven-point ideology measure and was not true in 2002 unless one used the seven-point measure (which Hacker and Pierson did not). Regardless, none of the differences between the two groups – in my results or theirs – are statistically significant due to the small sample sizes.

In sum, Republican activists have generally been at least as extreme as Democratic activists and often more so, though not in 2004, which makes the Republican pattern seem less worrisome. Furthermore, while in 2002 it looked like Republican extremism had increased and Democrats had become more moderate, by 2004 Democrats had completely caught up to Republicans. Republican and Democratic activists were equally far from the center in 1972 and in 2004, so the shift was of the same magnitude for both. And there’s no reliable evidence that Democratic activists are more moderate than other Democrats.

The Bush administration and the Republican Congress may have used various tactics in order to pass an agenda that lacked strong support. But they were not “off center” if that phrase is taken to mean that their agenda was outside the bounds of what the public supported. Or more specifically, where Republicans succeeded, their agenda was not out of bounds. Hacker and Pierson downplayed the extent to which Republicans had to reach out to the center in what they did or did not favor. Education spending, for instance, 
increased more under Bush than under Clinton, in a nod to “compassionate conservatism.” Furthermore, where Republicans truly moved off center, they failed, as with Social Security privatization. And of course, 2006 and 2008 happened.

(This is cross-posted from ProgressiveFix.com, the new online face of the Progressive Policy Institute, where I will be posting regularly.  Give 'em a look.)

OK, to review the debate so far: I wrote a post suggesting progressives might want to think twice before jettisoning the filibuster. Ed thought twice and said, yup, still want to get rid of it.  Ezra did the sameI wrote another post saying, oh well whatever nevermind and tried to shift the subject to polarization being the real problem. I said I’d follow up about whether increasing polarization has been a one-sided affair. Crickets chirped. All hell broke loose on the health care reform front. And here we are.

So….one-sided polarization….Ever since Jacob Hacker and Paul Pierson’s 
Off Center, all good progressives know that the growing political polarization has been one-sided, with Republicans pulling public policy “off center” through various nefarious means. Right?

Well….yes and no. Hacker and Pierson argued that, as of 2005, Republican activists and legislators had grown more conservative, but Democratic activists and legislators had not grown more liberal (and had even moved to the right themselves in some regards). Along with this shift, Republicans had developed effective strategies to move public policy further rightward than the typical voter preferred.

Since the rightward shift of Republicans occurred during a period in which Hacker and Pierson showed the distribution of self-identified ideology had not changed, the implication was that the electorate was being deprived of the more progressive policies that it desired. But a closer look at their data and analyses shows that while the increase in polarization among legislators has occurred disproportionately among Republicans, the evidence hints that this is because it proceeded from a Nixon-era Democratic Congress that was well to the left of the electorate.

Rather than refuting the idea that policy reflects the preferences of voters in the middle (the “median voter theorem”), as Hacker and Pierson claimed, the evidence actually bolsters this view. Correcting their claims is important if progressives are to govern effectively. Republicans did not simply pull public policy to the right of where Americans preferred, and now that Democrats are back in control of Congress, progressives should not assume that the median voter is leftier than she really is.

Why Off Center Is Off

To argue their case, Hacker and Pierson turned to scores created by Keith Poole and Howard Rosenthal that put members of Congress past and present on a common scale measuring ideological position. Hacker and Pierson report that the polarization of Congress between the early 1970s and the early 2000s was almost entirely due to growing extremism among Republicans. Democratic legislators had not moved nearly as far from the center. Because of the increasing conservatism of Republicans, Congress was, in the early 2000s, far to the right of the median voter, who had not grown more conservative over time. But Hacker and Pierson’s account is flawed.

Consider the Senate.* Poole and Rosenthal’s scores, using every vote by every member of every Congress through the 108th Congress (which ran from 2003 to 2004), indicate that the “center” as of 2003-04 was typified by northeastern Republicans such as Lincoln Chafee, then-Independent Jim Jeffords, and William Cohen; Arlen Specter (now, of course, a Democrat); and by red-state Democrats such as Ben Nelson and John Breaux. In 1971-72, the median senator had a score of -0.056, equivalent to Ben Nelson’s score in 2003-04. By 2003-04, the median senator had a score of 0.061, equivalent to Arlen Specter in 2003-04.

This small change in the median of the Senate as a whole only hints at the fact that, as Hacker and Pierson claim, Republican senators did move farther ideologically than Democratic senators. The evidence that Hacker and Pierson presented describes how the median in one year compared with then-recent senators’ scores. In the early 1970s, according to Hacker and Pierson, the median Republican senator lay “significantly to the left of current GOP maverick John McCain of Arizona—around where conservative 
Democrat Zell Miller of Georgia stood” [where the references to McCain and Miller are to their 2003-04 scores, italics in the original]. The median Republican senator’s score then “doubled” by the early 2000s so that it sat “just shy of the ultraconservative position of Senator Rick Santorum.”

These descriptions do not quite reflect what the Poole-Rosenthal scores show. The median Republican senator’s score in 1971-72 was 
equidistant between McCain in 2003-04 and Miller in 2003-04, not closer to Miller, and it was just as close to McCain as the median Republican senator’s score in 2003-04 was to Santorum.

This claim also raises a technical issue. The Poole-Rosenthal scores are not ratio scales with a meaningful zero point. The distance between 0.2 and 0.4 is supposed to be the same as that between 1.2 and 1.4, but 1.2 is not “six times as conservative” as 0.2, because a score of 0 does not indicate the complete absence of conservatism. The zero point is completely arbitrary. The doubling from 0.2 to 0.4 would become an increase of just 50 percent if we added 0.2 to all of the scores (from 0.4 to 0.6). We cannot know whether Republican senators grew twice as conservative between the early 1970s and the early 2000s. Indeed, the phrase “twice as conservative” has no obvious meaning.

More to the point, Hacker and Pierson’s interpretation of these results is an even bigger problem. Rather than the Republican Party drifting ever rightward (the whole time increasingly “off center”), if the Democratic Party was “off center” in the early 1970s, then the movement among Republicans could be interpreted as a restoration of an equilibrium reflecting voter preferences. This is exactly what appears to have happened.

First of all, the medians for the 2003-04 Senate were 0.379 and -0.381 for Republicans and Democrats – essentially identical. That means that after this great rightward shift by Republicans, the parties were equally “extreme” by historical standards. Furthermore, the median Democratic senator in 1971-72 wasn’t much less extreme than the median senator from either party in 2003-04.

Second, at least in terms of self-identification, the ideological distribution of Americans was unchanged over this period, with roughly twice as many people calling themselves conservative as calling themselves liberal.**

Taking these facts together – a rightward shift by Republican legislators, an end state where Democrats and Republicans are equally “extreme”, and an ideological distribution among voters that was static over the period (and right-leaning) – the conclusion that best fits is that the Democratic Congress of 1971-72 was off center rather than the Republican Congress of 2003-04. The median Republican became more extreme over time, but that was because Congress became 
more representative of the electorate, not less. The story on the House side is much the same, except that the median Republican was a bit more “extreme” than the median Democrat by 2003-04 (although no more extreme than the median Democrat was in 1971-72).

Comparing the Activists

Hacker and Pierson also argue that Republican activists grew more extreme while Democratic activists became less so (becoming even less extreme than Democrats in general), but these claims are also problematic. Hacker and Pierson began by defining an activist as someone who self-identifies as a Democrat or a Republican and who participated in three out of five election-related activities asked about in the American National Election Studies. They measured ideology using a combination of two “thermometer” items – one of which asks respondents how warm or cold they feel toward liberals and one inquiring about conservatives. These scales range from 0 (cold) to 97 (hot). (The scale ends at 97 rather than 100 because in some years, the NES used codes 98 and 99 as missing value codes.) The liberal score is subtracted from 97 (so that high numbers then signify cold feelings) and then added to the conservative score. This number is divided by two, 0.5 is added to it, and the decimal is dropped. The resulting measure ranges from 0 (extremely warm toward liberals and extremely cold toward conservatives) to 97 (extremely cold toward liberals and extremely warm toward conservatives).

To determine how far activists drift from the center, they compared the activist scores on this index to the scores for independent voters. The distance from independents is expressed in percentage terms (e.g., 10 percent more conservative or liberal). Hacker and Pierson plotted the average distance from independents for Republican and Democratic activists and then “smoothed” the trends by imposing curves to describe them. The result is a graph that I replicated, more or less:
The graph shows that Republican activists were more extreme than Democratic activists to begin with, that they became more conservative over time, and that after becoming more liberal, Democratic activists tacked back toward the center. The first important thing to note about this graph is how much the nice, smooth lines depend on fitting the data points to a quadratic equation. The original data – without the smoothing – looks much messier:
The upward trend among Republican activists is still readily apparent, but the trend for Democratic activists no longer points toward moderation. The bouncing around is partly due to different turnout patterns in off-year elections, but also a result of statistical noise, as the sample sizes for each group are less than 70 – and as low as 18 – in each year. Furthermore, Republican and Democratic activists are statistically the same distance from the center for much of the period between 1968 and 1992. To illustrate further how deceptive the smoothed trend lines can be, look what happens to them when 2004 data – which was not available when Hacker and Pierson created the graph – is added:
The Republican line hardly changes, but now Democratic activists appear to grow steadily more liberal. It still appears as though Republican activists drifted from the center more than Democratic activists did, and Republican activists look more extreme in all years.

OK, take a breather. Tomorrow I’ll wrap up with some revealing evidence about how Hacker and Pierson’s definition of “the center” affects these analyses of political activists.

To read the second part of this post, click here.


* Following their recent book, Polarized America (McCarty, Poole, and Rosenthal, 2006), I use scores on Poole and Rosenthal’s first DW-NOMINATE dimension (for details, see  
http://polarizedamerica.com/ and http://www.voteview.com). Hacker and Pierson report using “d nominate” scores, but these are only constructed through the 99th Congress, so I am inclined to believe that they too used the first DW-NOMINATE dimension scores.

** Hacker and Pierson (2004), page 38. Hacker and Pierson cite ANES data. According to Gallup data showing self-identified ideology, the breakdown among Americans as a whole in 2004 was roughly 20 percent liberal, 40 percent moderate, and 40 percent conservative (Wave 2 of the June Poll, Question D10). In 1972, it was 25 percent, 34 percent, and 37 percent (Poll 851, Question 14).