Take the A Train

I'm sure the terrible Amtrak derailment near Philadelphia that killed 8 people and injured 200 others captured your attention. Despite House Speaker John Boehner calling the idea “stupid,” there is reason to believe that Congressional budget cuts played a role in the accident by delaying the installation of positive train control, a signal system that would have automatically slowed trains traveling above the speed limit. In Mr. Boehner's simplistic world view, each event has one and only one cause. Therefore, if the accident can be attributed to human error, legislators are absolved of responsibility for cutting spending that would have protected passengers from human error. In sharp contrast to the usual political response to such tragedies, on the day after the accident, the House Appropriations Committee voted to reduce Amtrak's budget by another 15% next year. Highways and airports each receive about 45 times the subsidies that Amtrak does.

Amtrak's problems and our own will be compounded if the American people conclude that passenger trains are unsafe, especially if they decide to travel by car instead. Here are the data on annual number of deaths per mile travelled, supplied by Christopher Ingraham of the Washington Post.

Cass Sunstein, Administrator of the Office of Information and Regulatory Affairs during President Obama's first term, is a lawyer by profession, but his books and articles draw heavily on research in social psychology. In a recent op-ed, he mentions two reasons people might overreact to news of the Amtrak tragedy.

1. Probability neglect. When deciding on a course of action, a rational decision maker should weight the utility of each alternative by its probability. Sunstein coined the term probability neglect to refer to people's tendency to completely ignore probabilities when making their decisions. As a result, our actions are influenced far too much by low probability risks, such as the chance of a plane crash, and low probabilty benefits, such as winning the Powerball lottery.

Sunstein overstates his case when he claims that probabilities are completely neglected, but there is evidence from psychologist Paul Slovic and others that average citizens do a poor job of estimating the risks posed by various activities and technologies, when the judgments of experts are used as the criterion of accuracy. An example is nuclear power, which is judged to be much more dangerous by non-experts than experts. When experts make risk assessments, their estimates are largely determined by annual numbers of fatalities, while lay people's judgments are influenced by other characteristics such as catastrophic potential.

2. Availability heuristic. Sunstein's second reason that people might overreact to the Amtrak accident helps to explain some of our poor risk judgments. A judgmental heuristic is a simple rule that people use to make decisions quickly and without much thought. The availability heuristic, first identified by Amos Tversky and Daniel Kahneman, states that the frequency of some object or event is judged on the basis of how easily it can be brought to mind. For example, availability is influenced by proximity in space and time; that is, we are more likely to recall events that occurred nearby or recently. Please check out this brief explanation of the concept.
   
   

As noted in the video, one factor determining availability is the salience or emotional impact of an event. When asked to estimate the frequency of various causes of death, we overestimate those that are more dramatic, such as homicides and accidents, while underestimating more mundane causes, such as heart disease or diabetes. A followup study showed parallel differences in the amounts of attention given to these causes of death by the news media. Since the media usually devote more attention to infrequent events, such as plane and train wrecks, than ordinary, everday occurrences—the “man bites dog” phenomenon—they contribute to our tendency to overestimate the probability of rare events and underestimate more common ones.

My intent is not to criticize media coverage of events like the Amtrak accident. In fact, my first impulse was to include a picture of the accident, thereby making myself part of the problem. Our task, as critical readers, is to remind ourselves to place media publicity in its larger statistical context, and to start being less afraid of Ebola, for example, and more afraid of obesity.

You may also be interested in reading:

Death By Anecdote, Part 1

Good Studies Go to the Back of the Bus

Death By Anecdote, Part 1

You can lie with statistics, but a well-chosen anecdote is much more effective.

Here's something to look forward to, right along with your next colonoscopy.  The New York Times reports that the Republican Party plans to carry out a sustained, organized attack on the Affordable Care Act (ACA) for the next year, in the hope of gaining an advantage in the 2014 elections. The Republican campaign, described as a “multilayered sequenced assault,” is outlined in the House Republican Playbook, a 17-page strategy document prepared by their House leadership. It lists a series of talking points such as: “Because of Obamacare, I lost my insurance,” “Obamacare increases health care costs,” and “The exchanges may not be secure, putting personal information at risk.” House members are advised to collect anecdotes from constituents in support of these talking points through social media, letters and visits to their home distract. A new website, gop.gov/yourstory, centralizes the collection of these anecdotes. Republicans are instructed in the use of “messaging tools” for disseminating the stories, for example, a sample op-ed for submitting to local newspapers.

The idea is to flood the media with anecdotes in support of a particular talking point. If there is an effective counterresponse from Democrats, they will shift immediately to a different talking point. Topics waiting in the wings for possible use include insurance “rate shocks,” threats to being able to keep your doctor, and possible changes to Medicare Advantage policies.

The Republicans recognize that anecdotes can have a powerful influence on public opinion. When making inferences, people use judgmental heuristics, or mental shortcuts to make decisions quickly and easily. The use of heuristics is automatic and unconscious. They usually lead to correct inferences, but they sometimes lead us astray.

One inference we often make is to estimate the size of a category or the frequency of an event. For example, how many Americans are being harmed by the ACA? The availability heuristic suggests that the size of a category is judged by the ease with which examples can be brought to mind. Examples are more easily retrieved from memory if they are concrete rather than abstract, if they are dramatic and interesting, or if they happened recently or nearby. Personal experiences are particularly salient. When people are asked to estimate the frequency of various causes of death, they overestimate homicides and auto accidents, but underestimate strokes and diabetes. Clearly, their estimates are influenced by media coverage.

The problem gets worse when you consider the base rate fallacy, which states that people are inattentive to population statistics, and their judgments are not sufficiently affected by them. In one study, participants were given vivid stories about misbehavior by prison guards or welfare recipients. Attitudes toward these groups were equally negatively affected regardless of whether they were told that the anecdotes were typical of the population, not typical of the population, or they were given no base rate information. In another study, college students' intentions to take courses were affected by single brief face-to-face comments from a stranger, but hardly at all by statistical summaries of the course evaluations of much larger numbers of students who had previously taken the course.

The availability heuristic and the base rate fallacy suggest that even if people are given accurate information suggesting than the story is unrepresentative, their false impression is unlikely to be corrected. There was heavy media coverage of the first wave of anecdotes from people who claimed that their insurance costs went up due to Obamacare. When critics examined them more closely, many of these anecdotes were found to be misleading. Insurance companies cancelled policies and raised rates long before the ACA. The percentage of people whose policies were cancelled was small. Some of these people were able to get equal or better insurance through the exchanges without paying more. However, the corporate media can't be counted on to investigate anecdotes before airing them, and the debunking stories seldom receive anywhere near the attention given to the original report.

The Obama administration has apparently decided that the best defense is a good offense, so they are responding with anecdotes of their own—so-called Obamacare “success stories.” While this may be the best they can do under the circumstances, they are unlikely to get much cooperation from the corporate media in publicizing these stories. The media don't cover successful airplane landings--unless you land it in the Hudson River. Meanwhile, the administration and the media have largely overlooked another potential source of much more tragic stories: the 5.2 million people who are being denied health insurance entirely because they happen to live in states where Republican governors and legislatures have blocked Medicaid expansion. But to the corporate media, an upper middle class person losing a few dollars a month is much more newsworthy than a poor person losing his or her life.

But remember, the plural of anecdote is not data. To be continued.

You may also be interested in reading:

Death By Anecdote, Part 2

Policy By Anecdote

The Coverage Gap:  The Real Failure of Obamacare