Monday, August 29, 2011

Active learning: going mobile in India

I've been using "clickers" since 2002 in all my courses. Clickers are polling devices that students use during class to answer multiple-choice questions that I include in my slides. They encourage students to participate (even the shy ones), they give the teacher immediate feedback about students' knowledge, and are a great ice-breaker for generating interesting discussions. Of course, clickers are also fun. Most students love this active learning technology (statistically speaking, around 90% love it and 10% don't).

Clicker technology has greatly evolved since 2002. Back then, my students would watch me (in astonishment) climbing on chairs before class to place receivers above the blackboard, to allow their infra-red, line-of-sight clickers (the size of TV remotes) to reach the receivers. The receivers were the size of a large matchbox. Slowly the clickers and receivers started shrinking in size and weight...

A few years later came the slick credit-card-size radio-frequency (RF) clickers that did not require line-of-sight. My receiver shrunk to the size of an obese USB stick.

I still love clickers, but am finding their price (hardware and software) unreasonable for education purposes. The high prices ($40/clicker in the USA) are also applicable in India, as I've discovered (a quote of over $4,000 for a set of 75 clickers and a receiver raised my eyebrows to my hairline). In addition, now that everyone carries around this gadget called a mobile phone, why burden my students with yet-more-hardware?

This brought me to research using mobiles for polling. I discovered, which offers a facility for creating polls via their website, then embedding the polls into slides (Power Point etc.). Students can respond with their mobile phones by sending an SMS, tweeting, or using the Internet. I am especially interested in the mobile option, to avoid needing wireless Internet connection, smartphones, or laptops in class.

So, how does this work in India?
The bad news: While in the USA and Canada the SMS option is cheap (local number), does not have a local number for India (you must text an Australian number).

The good news: Twitter! Students with Bharti Airtel plans can tweet to respond to a poll (that is, send an SMS to a local number in India). I just tested this from Bhutan, and tweeting works beautifully.

The even-better news: Those using other Indian carriers can still tweet using the cool workaround provided by This allows tweeting to a number in Bangalore.

The cost? A fraction to the university (around $700/year for 200 students using the system in parallel) and only local SMS cost to the students. How well will this system work in practice? I am planning to try it out in my upcoming course Business Intelligence Using Data Mining @ ISB, and will post about my experience.

Wednesday, August 17, 2011

Where computer science and business meet

Data mining is taught very differently at engineering schools and at business schools. At engineering schools, data mining is taught more technically, deciphering how different algorithms work. In business schools the focus is on how to use algorithms in a business context.

Business students with a computer science background can now enjoy both worlds: take a data mining course with a business focus, and supplement it with the free course materials from Stanford Engineering school's Machine Learning course (including videos of lectures and handouts by Prof Andrew Ng). There are a bunch of other courses with free materials as part of the Stanford Engineering Everywhere program.

Similarly, computer science students with a business background can take advantage of MIT's Sloan School of Management Open Courseware program, and in particular their Data Mining course (last offered in 2003 by Prof Nitin Patel). Unfortunately, there are no lecture videos, but you do have access to handouts.

And for instructors in either world, these are great resources!

Thursday, August 04, 2011

The potential of being good

Yesterday I happened to hear talks by two excellent speakers, both on major data mining applications in industry. One common theme was that both speakers gave compelling and easy to grasp examples of what data mining algorithms and statistics can do beyond human intelligence, and how the two relate.

The first talk, by IBM's Global Services Christer Johnson, was given at the 2011 INFORMS Conference on Business Analytics and Operations Research (see video). Christer Johnson described the idea behind Watson, the artificial intelligence computer system developed by IBM that beat two champions of the Jeopardy quiz show. Two main points in the talk about the relationship between humans and data mining methods that I especially liked are:
  1. Data analytics methods are designed not only to give an answer, but also to evaluate how confident they are about the answer. In answering the jeopardy questions, the data mining approach tells you not only what is the most likely answer, but also how confident you are about that answer.
  2. Building trust in an analytics tool occurs when you see it make mistakes and learn from those mistakes.
The second talk, "The Art and Science of Matching Items to Users" was given by Deepak Agarwal , a Yahoo! principle research scientist and fellow statistician, was webcasted at ISB's seminar series. You can still catch it on Aug 10 at Yahoo!'s Big Thinker Series in Bangalore. The talk was about recommender systems and their use within Yahoo!. Among various approaches used by Yahoo! to improve recommendations, Deepak described a main idea for improving the customization of news item displays on

On the relation between human intelligence and automation, the process of choosing which items to display on Yahoo! is a two-step process, where first human editors create a pool of potential interesting news items, and then automated machine-learning algorithms choose which individual items to display from that pool.

Like Christer Johnson's point #2, Deepak illustrated the difference between "the answer" (what we statisticians call a point estimate) and "the potential of it being good" (what we call the confidence in the estimate, AKA variability) in a very cool way: Consider two news items of which one will be displayed to a user. The first item was already shown to 100 users and 2 users clicked on links from that page. The second was shown  to 10,000 users and 250 users clicked on links. Which news item should you show to maximize clicks? (yes, this is about ad revenues...) Although the first item has a lower click-through-rate (2%), it is also less certain, in the sense that it is based on less data than item 2. Hence, it is potentially good. He then took this one step further: Combine the two! "Exploit what is known to be good, explore what is potentially good".

So what do we have here? Very practical and clear examples of why we care about variance, the weakness of point estimates, and expanding the notion of diversification to combining certain good results with uncertain not-that-good results.