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Reflections on Fourth of July Parades—and False Causation

by Donald Prothero, Jul 06 2011


On Monday, my family and I attended the annual Fourth of July Parade in Sunland-Tujunga, California. We go nearly every year, and most years they have virtually the same lineup: lots of classic antique cars and hot rods and ATVs and  motorcycles, plus flatbed trailers and marchers from church groups, anti-abortion groups, Boy Scouts, Cub Scouts, and Girl Scouts, the local Lions, Kiwanis, and other social clubs, horses from the upscale Shadow Hills neighborhood (where movie stars with horses, like Patrick Swayze, lived), fire trucks (including a lot of antique fire trucks and ambulances that come from a company in Sun Valley that supplies them for movie shoots), minor movie stars, TV actors, and local officials—and a small portion of the local high school band (because they’re out of school and mostly out of town by mid-summer).

This is not your typical small town Fourth of July parade, because Sunland-Tujunga is not your typical small town. Once a foothill retreat from the city with lots of “mountain cabins”, it is one of the last Anglo enclaves in the City of Los Angeles. Long ago it was settled mostly by former hippies and bikers, so it is “redneck-NASCAR” heaven (mostly lower-middle class whites). Nearly all of the rest of the City of Los Angeles (and its school district) is largely Latino and African-American now. The parade is very casually organized, and almost anyone can march if they want to. Often, it drags on for more than an hour with large gaps between units, because there isn’t much control over the marchers (except for LAPD putting traffic barricades along the parade route). It is very different from the Rose Parade on New Year’s Day in nearby Pasadena, which is a highly professional, tightly run, multi-million-dollar enterprise with floats that cost more than most houses, and worldwide TV coverage. By contrast, the Sunland-Tujunga parade’s “floats” were mostly flatbed trucks with simple decorations, or old hay wagons pulled by tractors. There were a few changes from previous years: the parade was not led off by the LAPD motorcycle drill team (must be the budget cuts), but instead by a guy wearing a kilt and a cow-skull bike helmet ornamented with flags playing bagpipes on a unicycle. Then there was first for any parade I’ve seen: a float (actually a pickup truck) displaying the “oldest rock in Sunland-Tujunga”—although even from the sidewalk I could tell it was Mt. Lowe Granodiorite (220 m.y. old), not the actual oldest rocks in our local mountains, the Mendenhall Gneiss (1.7 billion years old)(check out the video link above—they actually did a very clever parody of geology, and the rock has its own Facebook page). There were very few local politicians (Congress is still back in D.C. fighting over the budget and the debt ceiling, so they can’t come home). And it was not nearly as political as in previous years, with only a few cars and people touting the local GOP club.

This reminds me of all the publicity attached to a report last week from Harvard Kennedy School Assistant Professor David Yanagizawa-Drott and Bocconi University Assistant Professor Andreas Madestam, which claimed to show a strong correlation between attendance at Fourth of July parades and later political leanings. According to the authors:

“When done before the age of 18, it increases the likelihood of a youth identifying as a Republican by at least 2 percent.

* It raises the likelihood that parade watchers will vote for a Republican candidate by 4 percent.

* It boosts the likelihood a reveler will vote by about 1 percent and increases the chances they’ll make a political contribution by 3 percent.”

What’s more, the effect isn’t temporary. “Surprisingly, the estimates show that the impact on political preferences is permanent, with no evidence of the effects depreciating as individuals become older”. According to Yanagizawa-Drott and Madestam:

“The political right has been more successful in appropriating American patriotism and its symbols during the 20th century. Survey evidence also confirms that Republicans consider themselves more patriotic than Democrats. According to this interpretation, there is a political congruence between the patriotism promoted on Fourth of July and the values associated with the Republican party. Fourth of July celebrations in Republican dominated counties may thus be more politically biased events that socialize children into Republicans,”

I’ve read and reread the original paper carefully, and I’m still not sure what to make of it. It seems clear that the authors were trying to tease out the effect of family, education system, peers, and other variables as predictors of future political leanings. If that’s all they were asserting—a strong correlation between regular parade attendance and family political leanings—then their conclusion should be no surprise. But the report could be interpreted to suggest that somehow a kid attending the parade each year would be inoculated by conservatism just by being there! That’s what a lot of the media have asserted who were reporting the story, as if seeing the parade zaps each kid with conservative memes and forever controls their future political thought processes. As usual, the media (and possibly the original authors) have the cart before the horse. First of all, it is questionable whether there is any validity to their conclusion. It’s just a single study with a small sample, which might be biased by how it was collected—such information is hard to tease out of the original document. The study has not yet been replicated, let alone been cross-checked for all the other confounding variables.

But let’s give them the benefit of the doubt and assume that the correlation is statistically supported. Once again, correlation does not prove causation. Seeing a Fourth of July parade probably does not mesmerize you with conservative political mojo. Rather, if you attend the parade each year, it is likely that you come from a more conservative family, and that will certainly be a strong predictor of a child’s future political ideas. As is typical of these instances of assuming causation from correlation, the real controlling factor is probably something that predicts a variety of different outcomes. Parade attendance almost certainly doesn’t cause conservative beliefs; the underlying cause is conservative familial beliefs which might predict both more frequent parade attendance and future beliefs of the child. Count on our modern media to fall into the trap of assuming correlation equals causation, and fail to ask the right questions, or to look past the superficial reporting on the original study.

A look at Fourth of July parades across the country suggests even more subtle factors at work. I’ve spent many of my Fourth of July holidays in small towns in Nebraska, Kansas, Illinois, Colorado, and eastern Oregon. There, the parades are largely about celebrating the community in such small towns, which don’t have many other major events to celebrate over the year (except the county fair in the late summer or fall).They certainly don’t have all the wonderful distractions of the beach, mountain skiing, major-league sports, concerts and theater, and other events that big cities like L.A. have on the Fourth. It is a bit surprising that for a city of over 7 million, there are only a few parades on the Fourth of July in Los Angeles. Instead, we have major parades for the Latino community at other times of the year, a major parade in South-Central on Martin Luther King Day, a  huge parade on Chinese New Year in Chinatown, and other parades that are tied to local ethnic holidays. Even among mostly Anglo communities, the more upscale neighborhood of La Canada, just east of Sunland-Tujunga (with a wealthier, better-educated demographic composed of JPL and Caltech employees), has a big Memorial Day parade, and there are equal numbers of local Democrat and Republican marchers. So the connection between parades and politics is much more complex, and reflects a lot of demographic and cultural factors besides patriotism on the Fourth.

As the demographics of the United States are changing, small towns across America are becoming even smaller, more Caucasian, more evangelical Christian, and older, which is the dominant demographic of the current GOP. The demographic groups that are growing fastest—Latinos and other minorities, young people who are more tolerant of gays and minorities, and the non-evangelicals—are the groups that turned out in large numbers to support Obama in 2008 (but stayed home in the 2010 elections). Lots of pundits and pollsters have pointed out that if the GOP ties its fate to the aging, evangelical Christian, conservative white part of the population, their base will shrink further and lose more elections, because that demographic group is vanishing as Latinos and other minorities, and more tolerant young people and non-evangelicals are quickly becoming the majority of voters.

Once, again, the media demonstrates its remarkable ability to misinterpret the evidence, and fails to look beyond the press release and ask the real questions that need asking. You could blame it on the tendency of the modern media to reduce everything to simplistic black-and-white sound bites. But it may also be influenced by the likelihood that few reporters or pundits know anything about statistics or social science, or how to dissect such reports using the basic principles of skepticism and critical thinking. Just think if these same reporters had a little sign saying “Correlation does not prove causation” taped above their computers!

21 Responses to “Reflections on Fourth of July Parades—and False Causation”

  1. Other Paul says:

    Probably the same everywhere. In the UK there’s St George’s day, mostly ignored for most of the latter half of the last century, but there’s a recent bit of resurgency. The flag’s the *English* flag (red crossed, white ground), not the UK flag. You’re likely to find the conservatives there. Certainly xenophobes are attracted to the englishness, so I expect they’d turn up rather than stay away. But that’s the thing, I don’t really know, I’d just feel unsurprised if it wers true. There’s just something about flagwavers, isn’t there?

  2. funkmon says:

    Mostly what I got here is that that little parade is bad ass.

  3. Max says:

    “Rather, if you attend the parade each year, it is likely that you come from a more conservative family, and that will certainly be a strong predictor of a child’s future political ideas.”

    If parade attendees are much more likely to come from a more conservative family, then the mere 2% increase in Republican identification might actually show how little it’s influenced by the family.

  4. Trimegistus says:

    I know that when this news came out the first reaction from a lot of conservatives I know was “Great, now the Democrats are going to ban parades.”

  5. Max says:

    I bet that children who attended a Chinese New Year parade are more likely to speak Chinese, and children who attended a Cinco de Mayo parade are more likely to speak Spanish and eat tacos.

  6. BillG says:

    Correlation does’t prove causation? Are homophobes mostly conservatives or most conservatives homophobes? I would venture either don’t attend gay pride parades too often.

  7. John K. says:

    2% is a really underwhelming number. Shows of patriotism have always been staples of the Republican party, I just wonder if this is a case of viewing a statistical error variation as evidence of what the authors of the study wanted to be true in the first place. Can 2% really be considered statistically significant?

    • Max says:

      A big enough sample can reduce the sampling error to get the p<0.05, but that still leaves various biases, which is why a bigger effect size is better.

  8. Tom says:

    I was afraid you were going to say the rock was billed as 6,000 years old.

  9. More false correlations? It appears those studies on obesity and “social contagion” aren’t what they cracked themselves up to be:

    However, showing once again that even actual science, not alleged science, isn’t perfect, the NEJM, per the story, is standing behind the claims.

  10. Murphy says:

    Jeez-Louise. I moved from Sunland a few years ago to Texas. I enjoyed Sunland’s 4th of July parade for 15 years. I still am a liberal Democrat (yeah, we have some of those in Texas). My son, who grew up watching and enjoying the parade, still thinks George W. was the funniest, most ridiculous president ever. If those two professors were US Congressmen (of either/both parties), that little study of theirs would have cost us millions of dollars in tax money. Parades are fun, no study required. It’s great to be out with your community in the heat for one day a year, for an hour to two hours, sitting alongside a hot, non-shaded street waving your little plastic American flag, watching your neighbors and business owners, small bands, twirlers, cowboys, volunteer firemen and a bagpipe player and ridiculous to think that it’s gonna sway a person to one political party or the other. It’s just gonna make you hot, sweaty, sunburned and ready and willing to do it all over again the next year. ‘Cause it’s the best, homegrown parade anywhere.

    • Donald Prothero says:

      @Murphy: I agree–but that’s what some people claim, and it made the national news just before the 4th, AGAIN with almost no critiquing or skepticism–and the Right Wingers touted it as evidence that THEY were True Americans and More Patriotic.
      Do you agree with my characterization of Sunland-Tujunga? I lived there for almost 10 years, then had to sell my house due to a divorce–but I moved to the Glendale School District, which was better for my kids than LAUSD.

  11. Richard Smith says:

    Yes, the question of whether watching a predominantly conservative event will (however slightly) turn you conservative, or conservatives are more likely to attend an event that is predominantly conservative is fairly deep, but I have a more important question after reading this line: “a guy wearing a kilt and a cow-skull bike helmet ornamented with flags playing bagpipes on a unicycle”.

    How can a flag play the bagpipes, and how can several of these gifted flags ride on a single unicycle (or is each flag’s set of bagpipes on its own unicycle?), and just how big is this unicycle in order to balance on the guy’s helmet? These are the things we need to know.