Assuming small differences are meaningful - Deepstash





The seven deadly sins of statistical misinterpretation, and how to avoid them

Assuming small differences are meaningful

Small, daily fluctuations are often just statistical noise. For instance, in the stock market or polls.

To avoid drawing faulty conclusions about the causes, request the "margin of error" relating to the numbers. If the difference is smaller than the margin of error, there is probably no real difference.


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The seven deadly sins of statistical misinterpretation, and how to avoid them

The seven deadly sins of statistical misinterpretation, and how to avoid them


Key Ideas

Assuming statistical = real-world significance

Generalizations about how two groups differ in some way often draw on stereotypes while ignoring the similarities.

Asking for the "effect size" can prevent this error. It is a measure of how much the average of one group differs from the average of another.

Not looking at extremes

A focus on a "normal distribution," - also known as a "bell curve," is where most people are near the average score, and only a small group is far above or below average. However, when you're dealing with extremes, small group differences can matter a lot.

Although a small change in performance makes no difference to the whole, the fluctuations change the character of the extremes.

Trusting coincidence

Just because two things change at the same time, or in similar ways, does not mean they are related.

Question the observed association. Are there many occurrences, or is this merely chance? Can you predict future associations?

Getting causation backward

When two things are related, one might be tempted to see a causal path. For instance, that mental health problems lead to unemployment. It is possible that it is reversed, such as unemployment, causing mental health issues.

When you think about the association, ask if the reverse is possible, or even if it could go both ways, creating a feedback loop.

Forgetting to consider outside causes

We sometimes forget to consider "third factors," or outside causes, that could be the link between two things, because both are actually effects of the third factor.

Avoid this error by always considering more factors when you see a correlation.

Deceptive graphs

A graph maker may choose a small range of a larger graph to highlight a little difference or association and make it look more significant.

Take care to note the graph's labels along the axes. Question unlabelled graphs.



Information that matches our beliefs

We surround ourselves with it: We tend to like people who think like us; if we agree with someone's beliefs, we're more likely to be friends with them.

This makes sense, but it means ...

The "swimmer's body illusion"

It's a thinking mistake and it occurs when we confuse selection factors with results. 

Professional swimmers don't have perfect bodies because they train extensively. Rather, they are good swimmers because of their physiques.

The sunk cost fallacy

It plays on this tendency of ours to emphasize loss over gain.

The term sunk cost refers to any cost that has been paid already and cannot be recovered. The reason we can't ignore the cost, even though it's already been paid, is that we're wired to feel loss far more strongly than gain.

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Straw man arguments

A straw man argument is a misrepresentation of an opinion or viewpoint, designed to be as easy as possible to contradict.

The only purpose is for it to be easy to expose. I...

Hollow man arguments

This is a weak case (similar to the Straw man arguments) attributed to a non-existent group: Someone will fabricate a viewpoint that is easy to contradict, then claim it was made by a group they disagree with. Arguing against an opponent which doesn’t exist is a pretty easy way to win any debate.

People who use hollow man arguments will often use vague, non-specific language without explicitly giving any sources or stating who their opponent is.

Iron man argument

It is designed to be resistant to attacks by a defier.There arguments are difficult to avoid because they have a lot of overlap with legitimate debate techniques.

A person using an iron man argument will most likely make their own viewpoint so vague that nothing anyone says about it can weaken it. They’ll use jargon and imprecise terms. This means they can claim anyone who disagrees didn’t understand them, or they’ll rephrase their argument multiple times.

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Homo Narrativus
Homo Narrativus

We, humans, seek stories.

We are essentially ‘story finders’ looking for meaning, narrative and shape in everything around us. We tend to not believe in improbable...

Bias Towards The Individual

Stories built around individuals provide relatability and a sense of being in the shoes of the people involved, living in the narrative.

Our tendency to give a ‘face’ and a story to a group or collection of people made us invent a dominant leader of the group, like the President, or the Team Captain, or the Monarch.

How Fame Alters Our Perceptions
  • The popularity or fame of an individual or a piece of art (like a painting, song or a movie) alters how we perceive it.
  • The characteristics and behaviour of the people among whom fame spreads matters more than the actual merit or quality.
  • A study showed that more people liked the songs that were topping the charts, copying the behaviour of other listeners, and if the same songs were arranged randomly, they were not chosen or liked that much.

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