Thursday, August 22, 2013

Tableau Public

There are lots of nice data resources out there - I've mentioned Quandl, DataZoa, and Knoema in the past.

I've recently been taking a look at Tableau Public, and it's certainly an interesting (and free) data visualization tool.

I liked this example from their Gallery - "Breaking the Law - Canadian Style"

© 2013, David E. Giles

Forecasting From Log-Linear Regressions

I was in (yet another) session with my analyst, "Jane", the other day, and quite unintentionally the conversation turned, once again, to the subject of "semi-log" regression equations.

After my previous rant to discussion with her about this matter, I've tried to stay on the straight and narrow. It's better for my blood pressure, apart from anything else! Anyway, somehow how we got back this topic, and she urged me to get some related issues off my chest. This is therapy, after all!

Right at the outset, let me state quite categorically that lots of people estimate semi-logarithmic regressions for the wrong reasons. I'm not condoning what they do. That's their problem - I have enough of my own! However, if they're going to insist on doing this, then I'm going to insist that they be consistent when it comes to using their estimated model for forecasting purposes!

I mean, we wouldn't use an inconsistent estimator, would we? So why should we put up with an inconsistent modeller?

Let me tell you all about it.........