Sometimes I get a bit narcissistic, and check how my book is doing. I log on to the seller portal to see how many copies have been sold. I go to the Amazon page and see what are the other books that people who have bought my book are buying (on the US store it’s…
The (missing) Desk Quants of Main Street
A long time ago, I’d written about my experience as a Quant at an investment bank, and about how banks like mine were sitting on a pile of risk that could blow up any time soon. There were two problems as I had documented then. Firstly, most quants I interacted with seemed to be solving…
Levels and shifts in analysing games
So Nitin Pai and Pranay Kotasthane have a great graphic on how India should react to China’s aggressions on Doka La. While the analysis is excellent, my discomfort is with the choice of “deltas” as the axes of this payoff diagram, rather than levels. Source: Nitin Pai and Pranay Kotasthane Instead, what might have been…
Newsletter!
So after much deliberation and procrastination, I’ve finally started a newsletter. I call it “the art of data science” and the title should be self-explanatory. It’s pure unbridled opinion (the kind of which usually goes on this blog), except that I only write about one topic there. I intend to have three sections and then…
Using all available information
In “real-life” problems, it is not necessary to use all the given data. My mind goes back eleven years, to the first exam in the Quantitative Methods course at IIMB. The exam contained a monster probability problem. It was so monstrous that only some two or three out of my batch of 180 could solve…
Means, medians and power laws
Following the disbursement of Rs. 10 lakh by the Andhra Pradesh government for the family of each victim killed in the stampede on the Godavari last week, we did a small exercise to put a value on the life of an average Indian. The exercise itself is rather simple – you divide India’s GDP by its…
The Art of Drawing Spectacular Graphs
Bloomberg Business has a feature on the decline of the Euro after the Greek “No” vote last night. As you might expect, the feature is accompanied by a graphic which shows a “precipitous fall” in the European currency. I’m in two minds of whether to screenshot the graphic (so that any further changes are not…
Airline delays in India
So DNA put out a news report proclaiming “Air India, IndiGo flyers worst hit by flight delays in January: DGCA“. The way the headline has been written, it appears as if Air India and Indigo are equally bad in terms of delayed flights. And an innumerate reader or journalist would actually believe that number, since…
Categorisation and tagging
Tagging offers an efficient method to both searching and for identifying customer preferences on the axis most appropriate for the customer The traditional way to organise a retail catalogue is by means of hierarchical categorisation. If you’re selling clothes, for example, you first divide it into men’s and women’s, then into formal and casual, and…
A/B testing with large samples
Out on Numbers Rule Your World, Kaiser Fung has a nice analysis on Andrew Gelman’s analysis of the Facebook controversy (where Facebook apparently “played with people’s emotions” by manipulating their news feeds. The money quote from Fung’s piece is here: Sadly, this type of thing happens in A/B testing a lot. On a website, it…
Nate Silver Interview At HBR Blogs
HBR Blogs has interviewed Nate Silver on analytics, building a career in analytics and how organizations should manage analytics. I agree with his views on pretty much everything. Some money quotes: HBR: Say an organization brings in a bunch of ‘stat heads’ to use your terminology. Do you silo them in their own department that serves…
Would you want a free membership card?
Last weekend I was at Cafe Coffee Day on MG Road, waiting to meet a prospective client, when one of the store staff walked up to me with a card. “This is a free loyalty card, Sir”, he said, going on to tell me that if I were to buy three coffees using the card…