A College Degree Increases Gullibility by 36%

My college statistics professor repeatedly told me that no one would want to read an article by a statistician, but he was 95% sure that 97% of news reporters (±3%) always report statistics incorrectly.

Case in point: Periodically the media report on a study that "proves" earning a college degree will increase your earning potential, and there is plenty of data showing that people with college degrees actually do make more money. However, what they usually fail to tell you is that the study (the one calculated by actual statisticians) cannot conclude that the college degree caused the increase in income.

... This is a post hoc fallacy at its best. It says that these figures show that if you (your son, your daughter) attend college you will probably earn more money than if you decide to spend the next four years in some other manner ... Actually we don't know but these are the people who would have made more money even if they had not gone to college. There are a couple things that indicate rather strongly that this is so. Colleges get a disproportionate number of two groups of kids: the bright and the rich. The bright might show good earning power without college knowledge. As for the rich ones ... well, money breeds money in several obvious ways. Few sons of rich men are found in low-income brackets whether they go to college or not. - Darrell Huff, How to Lie with Statistics [emphasis mine]

A report on a new study released by the Harvard School of Medicine now says that earning a college degree will increase life expectancy. To prove this, they cite data that show people with a college degree lived 7 years longer than those with a high school education or less. 

Take note that 7 years is enough time to finish a bachelor's degree and still have 3 years to spare.

Furthermore, at least one article says those who performed the study ruled out income disparities as a contributing factor to differences in longevity.

Assuming the model they used to perform the regression analysis was correct, this doesn't rule out the possibility that degree-earners live longer because:

1. They happen to be bright (and thus know that a healthier lifestyle increases their quality of life),
2. They have access to medical care (which is not necessarily tied to income), or
3. They are driven to excel (which may motivate them to pursue a degree in the first place).

In any event, to actually suggest a piece of paper is a magic pill that can improve health is so improbable that it is almost laughable.

By all means, get an education -- whether or not you also pursue a degree.

A good education can help you in any number of ways. But don't rely on misleading data to motivate you to do it, and don't presume that reporters are correct when they infer that your education starts or ends with -- or depends on -- a college degree. - Cam Beck

Comments

[Mario Vellandi]

Nice, that book is on my shelf waiting opening. Edward Tufte taught me how visual diagrams can also misrepresent data/info (or just be bad info design). The Ghost Map stressed correlation inferring causation. I think the overarching theme is be skeptical, especially of vague assertions, and examine assumptions made, sources, and methodology.

[Michael Lombardi]

While I would argue the point that colleges are filled with intelligent people, I'll stay on topic.

Anyone who thinks statistics like this show cause and effect belongs in a McDonalds--not near the fryer or the cash register, but in the play area.

Statistics show how strong a correlation is--they don't explain that strength or lack of strength in the correlation.

College graduates make more money and live longer. This could be for--and most certainly is--any number of reasons.

Here's another example: 100% of people who have dropped more than 4" off their waistline have lost weight. Could be from Weight Watchers, could be from exercise, could be from a tape worm. Then again, it could be all 3.

Of course without fancy graphs and numbers Al Gore wouldn't have an Oscar, a Noble prize and be an energy wasting hypocrite. Whoops, I suppose I was wrong about that last one--he was a hypocrite long before An Inconvenient Propoganda, erm, An Inconvenient Truth.

[Cam Beck]

Mario - The book was an incredible eye-opener. Everyone should have it on their reading list. What's more, it's a quick read, in spite of the subject matter.

Michael - As a point of clarification, the comment states that colleges *get* a disproportionate number of intelligent people, but the statement doesn't presume they're *still intelligent* when they leave. ;)

[Michael Lombardi]

Cam, think it's the declining American education system or the binge drinking? ;-)

[Jim Stroup]

It never fails to amaze me how people who should know better - and who lean heavily on their credentials to convince the rest of us that they do - make such boneheaded errors of logic - over and over.

Thanks for the tip to the book - on the list it goes!

[Cam Beck]

Michael - Yes. But both of those may have a common cause, too. :)

Jim - You won't regret it. It's an awesome book that should be on everyone's shelf and at the top of everyone's mind, whenever statistics are reported.