Tuesday, April 13, 2010

The Media's Interest in the Anti-Vaccine Movement

Over at Science-Based Medicine, Dr. David Gorski has written a post about email exchanges he had with a reporter named Steven Higgs. I exchanged some emails with Dr. Gorski myself, prior to his post, about some rudimentary data analysis Mr. Higgs had done with special education counts. I sent Dr. Gorski a number of graphs in order to illustrate Mr. Higgs' interpretation errors. Do check out the post.

What I actually wanted to discuss here is Dr. Gorski's observation about the apparent lack of anti-vax activity in Autism Awareness Month.
The anti-vaccine movement’s usual suspects haven’t been all over the mainstream media, as they usually are this time every year, often as early as April 1 or even March 31.

Could the anti-vax movement be losing steam? Are they regrouping? I have no idea. But we can check how much interest the media has had in the anti-vax movement in the last 13 years.



This is a graph of Google News Archive "autism vaccines" articles per 100 "autism" articles. Google News Archive has its own graphs where you can sort of see the trend as well, but it's methodologically better to look at article counts relative to "autism" articles, for obvious reasons.

I also added a VAERS "autism" submissions series to the graph. Clearly, media coverage of anti-vax speculation correlates well with VAERS submissions. See also how it compares to Sullivan's graph of the number of autism cases before the vaccine court.

2008 was a good year for anti-vaxers, given that it was the year when the Hannah Poling story broke, and Jenny McCarthy started to publicize her autism books on TV. But if you look at the graph, 2008 provided only a marginal boost. I doubt anti-vaxers will have another 2008 ever again.

That's the reality of the situation, even though in the blogsphere we seem to perceive things differently sometimes. Anti-vaxers often talk as though they are "winning the debate." Next time you find an anti-vaxer who says they are winning the debate, ask them what they are basing that opinion on, and send them over to this post.

12 comments:

  1. You should be covering and condemning the NC Medical Board from letting off Rashid Buttar. I get tired of you defending the establishment. Like I've been saying for years, you are hooking your wagon to a group that doesn't give a shit about our children. The fact that the NC Medical Board practically let this guy go with no punishment is, to me, more proof that establishments don't give a shit about autistic children/adults.

    Kent Adams

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  2. @Kent: Once again, there's only one person who decides what I should or shouldn't be covering, and (here's a hint) that would be me.

    Yes, I was appalled that they let Buttar go with a slap in the wrist. I don't blog every single thing that crosses my mind, though. In fact, sometimes I don't blog at all. Is that alright with you?

    Also, FYI, I don't hook my wagon to anyone, and I'm not as much a "defender of the establishment" as you think.

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  3. No, no, NC has a perfect plan! By making their state a perfect haven for quacks, they can draw in quacks from everywhere else, until the quacks all die because they have no one to turn to for actual medical help but each other. Or, alternatively, the military can nuke the state.
    Or is even this overestimating the Board's sanity and intelligence?

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  4. That's a major and recurring 'logic-fail' on Kent's part. he always wants to tell people what they should do.

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  5. Am I missing something? It seems the autism community is now touting the safety of vacines, as if this one trick pony aproach has any basis in logic. As compromised as Mr Wakefield's procedures were, his punishment does not answer any of the dozens of additional health issues with vaccinations including the forced government requirment on all cnildren. Why is there no debate on the natural immunity alternative? The conclusion that all vactinations are totally safe because a judge said there was not sufficient evidence provided at a trial to prove that MMR causes autism is just illogical, wrong and naieve.

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  6. I am not sure what it is that you think that your chart shows. Articles per 100 is a completely meaningless metric unless the number of autism articles is relatively constant.

    Over the past thirteen years, there has been more awareness/coverage of autism in general and that would result in more news articles being written. A quick search on Google news archive shows that there are at least 3-4 times as many articles in 2008 as there were in 1997.

    As the discussion about autism grew, I would expect that more topics would be covered and the portion spent on any one topic would shrink. Which is what your chart shows, more topics are being discussed concerning autism, not that any one topic is being discussed less.

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  7. @Dan: Yes, I think you're missing something. You're either making an off-topic statement, or you're attributing statements to me that I've never made.

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  8. @MJ: You're clearly wrong, and there are several ways to show you're wrong.

    First, if you simply search "autism vaccines" at Google News Archive, and you look at the absolute-count graph they produce there, you can tell that the absolute count also peaked around the 2002-2004 timeframe, although this is not as obvious as in my graph.

    It is perfectly valid to control the absolute count for the number of autism articles. The most important reason for this is that the number of total articles indexed by Google every year is bound to vary. Notice that I included 2010, so I absolutely had to control for something.

    You claim that as more autism articles are written, the presence of the word "vaccines" would get diluted in them. I fail to see why that would happen, unless reporters become less interested in mentioning vaccines in autism articles, or because they are covering autism science that increasingly excludes vaccine-related topics.

    I've actually analyzed other media trends like this, and you don't see the pattern you claim exists. I haven't actually written about this, but you can confirm it if you must. Try the same type of analysis with "autism recovered", "autism cured", "autism aba". You'll find a flat trend, at least since 1999 (there's a lot of noise prior to that.)

    Finally, there are several independent lines of evidence that confirm the peak of the modern anti-vax movement occurred in the 2002-2003 timeframe. There's the VAERS trend. There's Sullivan's graph of cases opened before the vaccine court. There's Smith et al. (2007) which tracks mother's concerns over the MMR. And there's a British report that indicates MMR coverage had a low in 2003-2004 and is recovering.

    That's the reality of the situation at the moment. Face it.

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  9. Joseph,

    First, your choice in search terms for terms might need to be tweaked. If you use "autism and vaccine" you get a slightly different picture.

    The number of articles in 2007 was 807, 2008 was 1870, 2009 was 1540, and so far this year is 479. If you adjust the last number you will see that we are on track for about 1300 articles this year.

    So, from 2007 to 2009 the number of articles almost doubled. I hardly call that losing interest. Although, since the number of stories in general about almost doubled from 2006 to 2009, I guess you could say the overall trend might be flat.

    Second, Google news archive is hardly a definitive source for media interest. There are many mainstream sites that are not included or are excluded at the site's request and then there is the fact that most blogs are not included. I think you can agree that blogs have become a much more important source of news since 2004 and excluding them introduces a significant bias.

    Third, I charted the "media interest" of the ND movement just for the fun of it. Look here http://bit.ly/bpPktm . While the "anti-vax" movement is staying more or less constant, the ND movement isn't even on the radar.

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  10. So, from 2007 to 2009 the number of articles almost doubled. I hardly call that losing interest. Although, since the number of stories in general about almost doubled from 2006 to 2009, I guess you could say the overall trend might be flat.

    You always need to control at least for the total number of articles, otherwise the results are completely biased, obviously. 2006-2007 was a low, and it's clear that there was a marginal boost in 2008 due to Jenny and Hannah Poling. I've noted that.

    I think you can agree that blogs have become a much more important source of news since 2004 and excluding them introduces a significant bias.

    The post is about mainstream media coverage, and I don't see why Google News would be biased against the anti-vax movement in this regard.

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  11. You might want to use the total number of articles as a control, but two data sets are highly correlated (~0.76) so I wonder at how well it works for that purpose.

    A better way of looking at the data might be a year over year change which would show you how the data changes in relation to itself. And by that measure, the number of media stories covering autism and vaccines has grown for 2 of the last 3 years (excluding 2010) and 8 of the last 13 years.

    For example, your "marginal boost" in 2008 is actually a 130% growth in the number of stories. At the same time, the number of stories about autism in general only grew 20%. That interest may have gone down in 2009 but it is still 90% higher than it was in 2007. And compared to the other high point (2004), 2009 is still 10% higher. Hardly a decrease in interest.

    As for bias - I didn't say it was biased but rather not a definitive source for media interest. If the data is of questionable quality that means the data might be problematic overall not that it is biased in one specific case.

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  12. My calculations show a 73% boost in 2008 for "autism vaccines" compared to 17% growth for "autism".

    I say it's a marginal boost in the grand scheme of things. Growth from 2001 to 2002 was 82%.

    As for bias - I didn't say it was biased but rather not a definitive source for media interest. If the data is of questionable quality that means the data might be problematic overall not that it is biased in one specific case.

    I don't see this making much of a difference overall. Google does archive all major newspapers. It archives many small newspapers. It has millions of articles. There's no reason to think its sample is skewed against the anti-vax movement.

    If anything, the fact that it indexes AoA might be problematic.

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