Chiropractic for Skeptics

Being a dedicated skeptic can be frustrating, especially in Arizona. The media is awash in stories people doing harm to themselves and others by having faith in pseudoscientific or magical cures instead of science-based medicine. Story after story, it’s the same: they waste time, money, emotional capital, and opportunity on ideas that do not work. They never learn and certainly never admit they were wrong.

This is not one of those stories.

Dr. Preston Long is a licensed Arizona chiropractor. He’s also one of the skeptical good guys. Dr. Long quit practicing after he realized that he was doing no good and possibly even doing harm. Now he is a consultant and author who testifies at malpractice trials involving chiropractic and educates consumers on the dangers of this questionable, yet ubiquitous, form of treatment. He is the author of several books, the most recent of which is titled Chiropractic Abuse: An Insider’s Lament. Chiropractors hate him, so you know he’s doing something right.

The following are my notes from Dr. Long’s August 10th, 2014 presentation titled “Chiropractic for Dummies,” sponsored by the Freedom From Religion Foundation Valley of the Sun Chapter. I added endnotes with my own sources when I could find them. Please keep in mind that the following are my interpretations of his statements. I do not quote Dr. Preston and I am not an expert, so please don’t hold him (or me!) liable for anything incorrect. That being said, enjoy!

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Chiropractic theory depends on the concept of subluxation. The claim is that chiropractic subluxations (not to be confused with orthopedic subluxations) are misaligned vertebrae that are responsible for most ailments.[1] Therefore, they are the primary focus of the chiropractor regardless of other medical issues. How can this be called medicine? Chiropractic is supposedly “separate and distinct” from other forms of medicine.[2] This means that even if a patient is experiencing symptoms from a real disease like cancer, for example, the chiropractor does not even attempt to treat the cancer—only the theoretical subluxations.

Arizona is a hotbed for chiropractic fraud. Regulation is ineffective because it is done solely by other chiropractors. They set their own standards and decide what meets them.[3]

Chiropractors billed insurance companies $496 million in 2012.[4] Virtually all were for the treatment of subluxations.

In Dr. Preston’s opinion, if a patient’s vertebrae were truly misaligned as chiropractors describe,[5] that person would most likely be in a wheelchair.

The placebo effect is responsible for much of the reported improvement after any therapy—including ones that have no actual therapeutic effect.[6] Surgery is the ultimate placebo.

A significant number of strokes are caused by chiropractic neck adjustments, especially for people under the age of forty-five.[7] Celebrity victims of chiropractic-induced strokes include Sharon Stone[8] and Kevin Sorbo.[9]

There is no legitimate medical diagnosis that calls for chiropractic neck adjustment as a treatment.[10]

Dr. Long distinguishes real physical therapy from pseudoscientific ones by the fact that true therapy is difficult and requires patient participation. Pseudoscience offers quick and easy solutions.

Chiropractic spinal adjustments can be especially dangerous for children[11] and animals.[12] Many chiropractors are struggling to find new adult human customers; children and animals represent a source of additional revenue. They are referral customers without the ability to consent.

The process of giving patients informed consent is mandatory for all health care providers. This means the patient must receive a thorough and accurate description of the procedure proposed, an objective assessment of the risks, benefits, and costs, and information on other options before undergoing any kind of medical procedure. In addition the healthcare provider must ensure the patient understands and explicitly consents to the procedure before proceeding.[13] It is common for chiropractors to omit these critical steps and perform adjustments on uninformed people.

The chiropractic business model: First, attract new customers with discounted treatments for common complaints like lower back pain or headache. Next, spend time chatting to make them feel comfortable and listened-to. Then, upsell them on other quackery like homeopathy, cupping, and acupuncture.[14] Finally, sign them up for a full-price, multiple-visit adjustment plan.[15]

Families comprising multiple generations of chiropractors run many chiropractic schools. School enrollment is down about 36% since the mid-1990s and has remained flat since 2002.[16]

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Meet other skeptics who support science-based medicine at Phoenix Skeptics in the Pub events. For more information and to join, check us out on Meetup.


















Cancer Quack Provokes Skeptical Action

Skeptics, this is a call to action! First, a story…

Once upon a time in Houston there was a quack named Stan. For decades Stan sold expensive yet ineffective cancer treatments to desperately ill people under the guise of scientific research. He got rich while his patients died. The federal government seemed unwilling to stop him.

Then, a group of concerned citizens pressured the government into finally putting Stan out of business. Stan went broke paying his legal bills and then went to prison and no one else was ever harmed by his quackery again.

Unfortunately, only the first part of this story is true…so far. That’s where we skeptics come in. We need to take action to pressure Congress to investigate Stanislaw Burzynski and–via the FDA or otherwise–put him out of business. We can be the heroic citizens from the story that raise hell about  injustice and win the battle against bogus medical treatments.

Thanks to the excellent work of skeptical activists David Gorski and Bob Blaskiewicz we now have all the information necessary. Please take a few minutes and visit The Houston Cancer Quack website where you will find the full story on Burzynski, instructions on how to contact your representatives, documents to send them, and everything else you need to educate them on the facts of this case and motivate them to launch an investigation.

Thirty-five years of quackery is enough, wouldn’t you agree?

For more information on Burzynski, see Science Based Medicine’s myriad articles on the subject.


Critical thinking in the classroom

One of my colleagues today gave her class a fairly simple task: pick 5 people that you would assign to go on a mission to explore a new planet.  I’ll tell you my list: geologist, engineer, astrobiologist, medical personnel, chemist.  It’s not the only list people could come up with.  I’m sure everyone reading this would come up with a slightly different list, but I’m sure there would be similarities: you’d pick people who could study the planet.

Want to know what the kids came up with? (keep in mind that these are sophomores and juniors in high school)

Doctor, lawyer, police man, teacher, construction person

Politician, doctor, farmer, army person, cook.

Builder, leader, doctor, teacher, business man

These are just a few examples of the lists, but I think it shows the point.  There is not a single scientist among them.  Not only that, some of the choices are pretty stupid.  Who the heck needs a business man with exploring a new planet?

Maybe the kids were confused on the assignment.  Maybe they thought their teacher was asking about colonization instead of exploration.  But still, most of the groups had no explanation for why they made their choices.  When asked why I would pick a geologist, I could explain that a geologist would be able to understand the composition of the planet.  Understanding the composition allows future colonies to know where to planet things, where to mine things, where the ground is stable enough to build things.  But these kids could not tell their teacher why they picked a police man to go explore a new planet.

Their lack of ability to explain their decisions shows an amazing lack of thinking things out logically and making decisions based on background knowledge and evidence.  And these are kids are the future.

Are you scared yet?

On the plus side, I had an amazing (although overly long as it was the first day of school and I had stuff to do) conversation about starting a class that would be all about getting kids to think critically.

So one of my (many) goals for the semester is to research content and curriculum ideas for a critical thinking class at the high school level.  Any ideas on where to start would be appreciated.

NASA Asteroid Initiative

NASA recently launched an initiative to capture an asteroid to study and possibly even mine for usable commodities. The technology—still in the speculative stage—would use a solar-powered robot to basically bag-up a small asteroid (around 20 feet in diameter) and move it into a stable orbit around the moon.

Among the experts called to review and voice opinions about the initiative was Dr. Jim Bell, an astronomer and planetary scientist at ASU’s School of Earth and Space Exploration. He voices skepticism about the project, citing nonexistent technology, unknown costs, and the rarity of suitable candidates for capture. This last point is significant; of the 10,000 known asteroids orbiting our sun, only about 370 are small enough to be eligible. Of these, only 14 are in acceptable orbits. In light of these difficulties, Dr. Bell advises “a mix of skepticism and excitement” instead of wild-eyed optimism.

This is how NASA describes the mission:

The asteroid grand challenge complements NASA’s mission to find and capture a near-Earth asteroid, redirect it to a stable lunar orbit and send humans to study it. The asteroid redirect mission is included in President Obama’s fiscal year 2014 budget request for NASA, and leverages the agency’s progress on its Space Launch System rocket, Orion spacecraft and cutting-edge technology development. The mission is one step in NASA’s plan to send humans to Mars in the 2030s.

False Positives and the Base Rate Fallacy

This weekend was The Amaz!ng Meeting! If you haven’t been, it is an “amazingly” fun gathering of critical thinkers with tons of excellent talks on skeptical, scientific, and thought-provoking topics. I wasn’t able to attend this year, but lived somewhat vicariously through the Facebook posts of a friend and fellow skeptic. The post below inspired this blog entry.


Although I have not seen Harriet Hall speak on this topic, I presume she intelligently articulated her reasons for this stance as she has in her writing (e.g. here and here).  I thought I’d take a moment to explain the math behind screening tests in support of the argument that it is risky to over screen for disease.

In classical measurement theory, sensitivity and specificity are statistical measures regarding the outcome of any binary (i.e. two-outcome) test. Let’s consider medical tests in terms of a positive result (diagnosis of disease/condition) and a negative result (free of the disease/condition). Sensitivity is a measure of the “true positive rate” and is the proportion of positive results that are correct positive results. Specificity is a measure of the “true negative rate” and is the proportion of negative results that are correct negative results. Consider a test for pregnancy. There are four possible results as shown in the table below: a. pregnant woman gets the correct positive result, b. non-pregnant woman gets an incorrect positive result, c. pregnant woman gets an incorrect negative result, and d. non-pregnant woman gets a correct negative result. The sensitivity of a pregnancy test is the percentage of time a woman who IS actually pregnant will get the correct positive pregnancy result. The specificity of a pregnancy test is the percentage of time a woman who IS NOT actually pregnant will get the correct negative result.


We calculate sensitivity as the proportion of people who correctly get positive test results. If each cell represents the number of people in the sample with the corresponding test result and actual condition status, then Sensitivity = A/(A+C). Notice that sensitivity only incorporates data from people who actually have the condition.

We calculate specificity as the proportion of people who correctly get the negative test results. When each cell represents the count of people from the sample with a particular test result and condition status, Specificity = D/(B+D). Notice specificity only incorporates data from people who don’t have the condition.

Ideally, we want all medical tests to have 100% sensitivity and specificity, but the reality is that most medical tests do not have that level of precision. However,  tests need to be developed  balancing both sensitivity and specificity as an increase in one often means a decrease in the other.  For example, consider an HIV diagnosis. Sensitivity is particular important as you don’t want to miss diagnosing someone with HIV; you want to help further prevent spreading of the disease and to start the patient’s treatment promptly. On the other hand, if the test gives too many false positives, it would cause a great deal of unnecessary emotional distress.  That brings us to the math! If a test has 99% sensitivity, then for every 100 people with the disease, 99 would be correctly diagnosed and 1 would have false negative and a missed diagnosis.  If the same test has 99% specificity, then for every 100 HIV-negative people, 99 would correctly get a negative result and one person would get a false positive. Both balancing and maximizing sensitivity and specificity are considerations in the design of diagnostic tests.

Base Rate Fallacy

The so-called “Base Rate Fallacy” comes into play in terms of medical diagnoses. Broadly, the base rate fallacy is when a person makes a judgment of the overall likelihood of an event based on easily accessible knowledge (here: values of sensitivity and specificity) without taking into consideration the prevalence or base-rate of the event. Here, we make the base rate fallacy when take the results of the test and fail to incorporate the actual rate of disease/condition. Rate of Disease = (A + C)/(A + B + C + D) 

Let’s consider a fictitious, deadly disease, Disease X. Disease X is very rare and only afflicts .01% of the population. Your doctor has a cheap and very accurate test: it has both 99.5% sensitivity and specificity.  Because the test is inexpensive, he or she has decided to administer this test to all of his/her patients (should this scenario be true, it would be time to find another doctor). You think, “This is great! I’d love to know for sure that I don’t have Disease X.” The doctor does the test and it comes back positive. You panic, hire a lawyer to write your will, and start saying your goodbyes because death is surely imminent. After all, the test has 99.5% specificity, doesn’t that mean that you most likely have the disease (a 99.5% chance!).  But is death imminent? What is the probability you actually have this disease? After the initial panic subsides, you take a step back and think about the actual probability that you have the disease and discover you made the “base rate fallacy.”

Let’s walk through this. We need to calculate the probability that you have the disease given the positive results of the test. Conventional notation expresses the probability of a disease given a positive test result as P(Disease|Positive). Recall that sensitivity is the probability that a person gets a positive test result given they have the disease. This can be expressed as P(Positive|Disease).  The base rate fallacy is the assumption that P(Disease|Positive) =P(Positive|Disease). However, the actual probability of the disease given a positive diagnosis based on the disease’s low base rate (assuming no other risk factors or variables are known) can be calculated.  NOTE: This is about to get very “mathy”. If math isn’t your cup of tea, just scroll down for the results. The results illustrate the point and it is not crucial you understand the math.  

Using Bayes’ Theorem, the probability of the disease given a positive diagnosis is expressed below.


The probability of a positive diagnosis can be expressed using the rules of probability and the equation above is equivalent to this equation.


Although the Equation above may seem a bit intimidating, we know the values to plug in:

P(Positive|Disease) = Specificity = 99.5% = .995

P(Disease) = Base Rate = .01% = .0001

P(Positive|NoDisease) = 1 – Specificity = .005

P(NoDisease) = 1 – P(Disease) = .9999

Plugging these values into the equation, we get:



Based on the math, given a 99.5% specificity and a .01% base rate, a person with a positive test result has less than a 2% chance of having the disease!!!  And just a slight decrease in specificity, the rate goes down further (for 99% specificity there is less than a 1% chance of actually having the disease given a base rate of .01%). Although no one wants to hear that they have 2% chance of having a deadly condition, this is certainly better than the original panic over the 99.5% accuracy test! Given that low base rate diseases can have high rates of false positives, it is prudent for doctors not to over test and cause unnecessary distress.

Although the example I’ve given for the base rate fallacy is in terms of medical diagnostic testing, the base rate fallacy is broadly applicable to many types of scenarios.  For example, consider the low rate of terrorists in the US and thus the resulting accuracy of any sort of screening procedures – there will be many false positives. Psychologists have also studied this phenomenon and found that humans tend to fall prey to the base rate fallacy in their decisions and judgments (e.g. Kahneman & Tversky, 1985). Anytime you make judgement about the probability an event based on information at hand while ignoring the base rate of the event, you are making the base rate fallacy. In conclusion, I hope that you will 1) be prudent about interpreting the results of any medical tests and ask questions regarding sensitivity, specificity, and rate of disease and 2) be on a keen lookout for ways the base rate fallacy may influence your own decision making or be used to manipulate you in advertising and the media.

The Amaz!ng Meeting

Every year in summer, hundreds of skeptics gather from around the world in southern Las Vegas for the “meeting of the tribes”: The Amaz!ng Meeting (TAM). This four-day monster of a conference is put on by the James Randi Educational Foundation (JREF) and is the highlight of the skeptical year for those who make the annual pilgrimage.

What is TAM?

TAM is a four day skeptic conference held from July 11-14th in Las Vegas. According to the website:

This annual gathering of critical thinkers is an unparalleled opportunity to make like-minded friends, enjoy some of the brightest minds on issues important to us, and leave with tools for spreading a helpful and skeptical message to those who might be hurt by charlatans and unfounded belief. TAM is like a vacation from the nonsense we confront every day, and a time to celebrate skepticism.

Why go to TAM?

Speakers include skeptic celebrities such as James Randi, Michael Shermer, Susan Jacoby, Jamy Ian Swiss, Jerry Coyne, Barbara Drescher, David Gorski, Steven Novella and the Skeptics Guide to the Universe crew, Harriet Hall, Richard Saunders, and too many more to list! If that weren’t enough, there are also many special events outside the lectures and workshops: a Drinking Skeptically meetup, Penn Jillette’s Bacon & Donuts Party, and the Skeptic Poker Tournament to name a few. However, my favorite reason for attending TAM is making and maintaining friendships with skeptics from around the world. This will be my fifth year in a row, and I’m excited to see my TAM buddies!

What is the venue like?

The South Point is located…you guessed it…on the south side of Las Vegas. It’s way-way off the strip, which is actually a good thing because it encourages everyone to hang out together. It has everything: restaurants, bars, gambling, a pool, a movie theater, and even an equestrian center. Each night the skeptics coalesce around the Del Mar Lounge. That’s where you’ll find me.

I hope you can make it to TAM…if not this year than the next. It’s a wonderful thing to be surrounded by so many fun, interesting, and rational people!

- Matt

For more information on TAM and to register, visit

To join the Phoenix Skeptics in the Pub meetup group, visit

WANTED: Educators

The PASS is looking for teachers to help create educational materials for use in and out of the classroom that feature scientific inquiry and critical thinking. The goal is to produce a set of ready-to-use lessons for teachers in a variety of grade levels and subjects. If you are an educator or otherwise involved in education and would like to participate in grassroots skeptical outreach, please contact me at

WANTED: Writers

The PASS is looking for writers for short monthly pieces on topics of skeptical interest. They can be about anything from classic skeptical topics like UFOs, psychics, and conspiracies, to modern issues like vaccines, evolution, and climate change–and just about anything else of interest to skeptics (science, food, finance, government, health, technology, consumer protection, pop culture, etc.)

If you’re interested in contributing to the local skeptical movement in the greater Phoenix area, please contact me at

- Matt

February Book Club – Gender Differences

This book club meeting was a point/counter point between two books with varying views. We read The Red Queen: Sex and the Evolution of Human Nature by Matt Ridley (2003) and Delusions of Gender: How Our Minds, Society, and Neurosexism Create Difference by Cordelia Fine. The group felt that each of these books strongly took one side of the nature vs. nurture debate. The Red Queen argues that gender differences are based in nature and Delusions of Gender argues for nurture. Members discussed the idea that culture and genetics inform each other; culture can affect genetics just as genetics can affect culture. In a sense, culture is a continuum that is constantly changing and “evolving” from previous renditions. The group discussed the authors’ biases towards their standpoint given Ridley’s background in zoology and Fine’s background in psychology.  The group was somewhat skeptical of the quality of evidence presented, particularly in the Delusions of Gender which argues that cultural assumptions cause gender differences.  The group would have liked to see more concrete examples of studies including information on methodology, sample size, effect size and resulting significance tests. The group conceded that if the evidence Fine produced held up under scrutiny, society may then need to consider Fine’s arguments about our culture causing gender differences.

Join us next month on March 15 for a discussion on Chris Mooney’s The Republican Brain. From

Science writer Chris Mooney explores brain scans, polls, and psychology experiments to explain why conservatives today believe more wrong things; appear more likely than Democrats to oppose new ideas and less likely to change their beliefs in the face of new facts; and sometimes respond to compelling evidence by doubling down on their current beliefs.

March’s book club comes immediately after an upcoming special event: A Evening With Chris Mooney on Monday, March 11, 2013. It will be interesting and fun to discuss Mooney’s book after meeting him in person. Don’t miss either event!

(Special thanks to Rose for helping with this entry in my absence.)

January Book Club – Evolution and Genetics of Food

January’s book club explored the issue of our food supply: Why do humans eat what we eat? Where does it come from? How have humans changed food? Has food changed us? To begin, we discussed Michael Pollen’s “Botany of Desire: A Plant’s-Eye View of the World.” In this book, Pollan claims that flowers and plants are not passive participants, and instead are lively participants in the process of coevolution with humans. Pollan asserts that some plants satisfy basic human desires. In his book Pollan details four such examples: (1) apples represent sweetness, (2) tulips represent beauty, (3) marijuana represents pleasure and (4) potatoes represent sustenance.  In the depiction of these plants’ abilities to satiate human desires, Pollan paints a picture of coevolution whereby plants aren’t passive and may actually be using humans to survive similarly to the way humans use plants to survive.  In general, book club readers liked this book but some members found this book to be a bit to verbose and lacking sufficient scientific support.

Next we discussed Mendel in the Kitchen: A Scientist’s View of Genetically Modified Food by Federoff and Brown. This book attempts to tackle the issues of whether genetically modified food is safe and whether common safety concerns are valid. The book describes the history of agriculture and plant modification beginning with the so-called “natural” breeding processes to the more modern “genetic modification.”  The authors argue that genetically modified food isn’t much different from “natural” hybrid crosses farmers have been using for many years, and assets that this method is less likely to result in error. The authors also explain how the use of genetically modified food could reduce the amount of pesticides and fertilizers in the environment while simultaneously feeding a fast growing population.  Those members of the book club who were wary about genetically modified food were somewhat swayed by this book’s pervasive and well-backed arguments regarding the safety of genetically modified food and its potential for environmental conservation.

Join us on Friday, February 22 for our next Skeptic Book Club Discussion on Gender Differences. We will be reading two books with varying views on the issue: The Red Queen: Sex and the Evolution of Human Nature by Matt Ridley (2003) and Delusions of Gender: How Our Minds, Society, and Neurosexism Create Difference by Cordelia Fine (2011).  Please check out Phoenix Skeptics in the Pub at for more information and to RSVP.