I was familiar with this technique, had used it in a couple of places. This week I had a chance to apply this technique to a problem at hand. However, this time I did not want to rush in . Had in my archives an old book called “User’s guide to Principal Components”. Took some time out to know a bit more about the technique. As always, there is always some new learning by reading old stuff.

Parsimony is desirable but not always obtainable - Edward Jackson (PCA Practitioner) I guess it’s true sometimes, about of our lives too !.

With easier access to raw computing power, one might think that all it takes is to analyze data and let the data throw hypotheses. Is theorizing over in this data intensive world ? Has the world become so complicated that theorizing is useless? May be not. I read this short note(Tom Swift and His Electric Factor Analysis Machine) couple of years back but I always reread it frequently so that I dont make the mistake of living only in an empiricist world.

Via NYTimes: Robert Gentleman & Ross Ihaka (people behind R) “R is a real demonstration of the power of collaboration, and I don’t think you could construct something like this any other way,” Mr. Ihaka said. “We could have chosen to be commercial, and we would have sold five copies of the software.” “The great beauty of R is that you can modify it to do all sorts of things,” said Hal Varian, chief economist at Google.

Often times most of the data / variables that we come across appear random and we start taking decisions based on gut. If gut works , its great. However before bringing in the gut part , it might be sensible to stretch a bit and look at data carefully and examine the details.Some time, just by changing the our view, we might see patterns. well PCA is all about that. I don’t have to go that far to make this point.