## Numbers rule your world

Andrew Gelman gave me a copy of the recent book Numbers rule your world by Kaiser Fung, along with the comment that it was a nice book but not for us. I spend my “lazy Sunday” morning reading the book at the breakfast table and agree with Andrew on his assessment. (waiting for theĀ  incoming blog review!). Numbers rule your world is unlikely to bring enlightment to professional or academic statisticians, but it provides a nice and soft introduction to the use of statistics in everyday’s life, to the point I would encourage my second and third year students to read it. It covers a few topics that are central to Statistics via ten newspaper-ised stories that make for a very light read, but nonetheless make the point. The themes in Numbers rule your world are

• variability matters more than average, as illustrated by queuing phenomena;
• correlation is not causation, but is often good enough to uncover patterns, as illustrated by epidemiology and credit scoring;
• Simpson’s paradox explains for apparent bias in group differences, as illustrated by SAT score differences between black students and white students;
• false positives and false negatives have different impacts on the error (here comes Bayes theorem!), depending on population sizes and settings, as illustrated by the (great!) case of cheating athletes and polygraph tests (with a reference to Steve Fienberg‘s work);
• extreme events may exhibit causes, or not, as illustrated by a cheating lottery case (involving Jeff Rosenthal as the expert, not the cheater!) and a series of air crashes.

The overall tone of Numbers rule your world is pleasant and engaging, at the other end of the stylistic spectrum from Taleb’s Black Swan. Fung’s point is obviously the opposite of Taleb‘s: he is showing the reader how well statistical modelling can explain for apparently paradoxical behaviour. Fung is also adopting a very neutral tone, again a major change from Taleb, maybe being even too positive (no the only mention is made of the current housing crisis in the pages Numbers rule your world dedicates to credit scoring comes in the conclusion, pp. 176-7). Now, in terms of novelty, I cannot judge of the amount of innovation when compared with (numerous) other popular science books on the topic. For instance, I think Jeff Rosenthal’s Struck by Lightning brings a rather deeper perspective, but maybe thus restricts the readership further…

### 3 Responses to “Numbers rule your world”

1. [...] scope of this blog, but for further commentary, see reviews by Wayne Hurlbert, Andrew Gelman, and Christian Robert. Share and [...]

2. Kaiser: Sorry, I did miss this part on pages 176-177. I quite agree that the crisis cannot be blamed on poor statistical modelling but on greed first and on poorly assessed complex financial products second. I like your sentence “The incentive structure is never static” because most of the black swans can be blamed on shifts in the models.

3. Christian: thanks for the review. You rightly point out that my objective is to bring more people into the field of statistics, and so I keep the technical content to a minimum. I discussed the credit crisis briefly in the Conclusion chapter, the point being that credit scores provide merely a ranking, and in reality, the excessive risk-taking represented the shift in power away from risk managers (who are concerned about potential losses) to sales managers (who are concerned about lost sales) when times were good. I think statistical models are easy to blame since they can’t fight back!