[Book Summary] The Data Detective by Tim Harford
Great grasps of intuition behind statistics, and how to approach them better
Author: Tim Harford
Title: The Data Detective: Ten easy rules to make sense of statistics
Published on: 2021
Tim Harford is a very optimistic individual that will help us better understand numbers and figures when presented as statistics in his latest book, The Data Detective.
The aim of this book is to make the reader aware about how useful statistics have been since their use has proliferated, but that we need to be curious, pragmatic and thorough when approaching them by following ten clear and easy-to-understand rules.
Rule 1: Search your feelings
As human beings, we are mainly driven by feelings. The first rule, while being the most fundamental one, states that we need to detach our emotional feelings from data when we are looking at it.
Look at data, check out your emotions, and don’t jump into conclusions too quick if your feelings are streaming down your brain!
Rule 2: Ponder your personal experience
We tend to be overconfident in regards to explaining what we see with our own eyes, “our truth”, and this usually leads us to look for causalities. Bear in mind that causality might be difficult to explain even with great statistics, but impossible without them.
Therefore, the second rule is to leverage the two different points of view regarding the world in general: the worm’s eye, or the personal experience that one has acquired over the years; and the bird’s eye, or the broad but dry insight we get from stats.
Rule 3: Avoid premature enumeration
We always need to be sure about what we are talking about when presenting numbers: if you listen that there’s a prevalence of self-harm among young people, try to understand how self-harm is being defined; or if you read that inequality has soared during the last years, make sure you know what kind of inequality is being measured.
Most of the times, newspapers articles and news will show you half the truth. It is your job to be curious enough to disentangle the other half.
Rule 4: Step back and enjoy the view
Daily news tend to be alarming and to leave you with a sense of short-term memory information overload. The main point of this rule is to slow down the process, get into the context, and spot the main takeaways correctly.
Avoiding alarmism and advocating for long-term, slow-paced information to better understand the context and to get an improved sense of the trend.
Rule 5: Get the back story
Trying to understand the story behind the data is as important as the data itself: is the data omitting something relevant? Is the report missing anything in particular? Are all the findings crystal clear?
To make it to the point, this is the author’s proposed exercise in this chapter:
After reading an article or a Facebook post describing some cool finding, just ask yourself how you’d explain it to a friend.
Do you know what the researchers did, and why, whether the research was a shock or exactly what experts would have expected? If not, you’re probably in front of just poor journalism.
Rule 6: Ask who is missing
Big data is starting to be the new normal: tons and tons of information for which only the collectors know what data is being gathered. It is quite possible, though, that the data is biased, meaning that important assumptions might have been made when results are shown.
As stated in the read, do not let the assumption “N (dataset observations) = All” rule your analysis, and always be aware of who might not be considered within the data you are dealing with.
Rule 7: Demand transparency when the computer says ‘no’
Statistical analysis on small datasets tend to be easy to assess and audit: we do not need fancy algorithms to draw conclusions. On the other hand and since big data started to shine, other more refined approaches surged.
These advanced algorithms usually bring better results to the table, but at the cost of becoming “black-boxes” that are not easy to interpret. Embrace the hype, but do not take these new methodologies as north stars!
Rule 8: Don’t take statistical bedrock for granted
Corrupted governments and politicians, as historical evidence showed, are able to tweak national statistics numbers in order for them to look the way they want them to look.
This doesn’t mean, though, that statistics organizations are not filled with great independent statisticians/economists that will always thrive to deliver the most accurate figures possible.
Rule 9: Remember that misinformation can be beautiful
Behind every graph, there will probably be someone trying to persuade you on taking a specific action: let it be a politician trying to convince you that her new regulation is working wonderfully, or a coworker showing off the great impact of her last proposed feature.
Don’t forget that we show what we want to show, and that all of us tried to persuade someone at any given point in our lives. There is nothing wrong on being persuaded, and it is absolutely not a problem to change our minds.
Rule 10: Keep an open mind
The last of the ten rules is somehow related to the rest, but specially to the first one. My main takeaway would be to be aware when emotions kick in, and do not feel embarrassed when things need to change, that’s what statistics are for.
We’ll finish by quoting one of the most renowned economists of all times, John M. Keynes, and probably one of the many reasons he was considered as so:
When my information changes, I alter my conclusions. What do you do, sir?
CONCLUSION
This is definitely not the typical boring and tedious statistics book. It catches your attention at every example since Mr. Harford has a very unique writing style that keeps you reading chapter after chapter.
It makes you think, it makes you question many things and, most importantly, it helps you realize that statistics, even though they are an exact science coming from maths, can derive to a wide array of interpretations.
Embrace all the unknowns that surround you, be curious, and do not forget to ask non-judgemental, authentic questions!
Great job Aleix!