Don't use Scatterplots

In a series of blog posts, Gary Rubinstein attempts show that the Value Added Modelling scores recently released by the NYC Department of Education prove that VAM (Value Added Modelling) is not accurate.

However, whatever flaws VAM may have, Gary Rubinstein (henceforth GR) hasn't demonstrated them. All he has demonstrated …

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Subpenny rule elimination - roundup

Just thought it's worth pointing out a couple of responses to my post proposing the elimination of the subpenny rule.

Alex Tabarrok discusses this on Marginal Revolution. In particular, look at David Krych's comment criticizing my proposal - I haven't had time to fully evaluate it, but it seems insightful.

Dealbreaker …

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Unemployment and market clearing

In a recent blog post, Karl Smith defends U3 from it's critics. The majority of his defense is spot on - U3 is a consistent, well-understood measurement which we can use to measure changes over time, and we also have a pretty good understanding of it's relationship to other relevant quantities …

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A High Frequency Trader's Apology, Pt 1

I'm a former high frequency trader. And following the tradition of G.H. Hardy, I feel the need to make an apology for my former profession. Not an apology in the sense of a request for forgiveness of wrongs performed, but merely an intellectual justification of a field which is …

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In-app caching - spend a little RAM to speed up your site

HTTP is a stateless protocol. For this reason, it's often considered bad practice to store data in your server's memory the memory of your webserver to be a bad practice. In general, this is correct - your webserver's ram is a bad place to store permanent data. It's volatile, and if …

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One Hiring Filter that Works

In a fairly popular blog post, Raganwald advocates against using various heuristics while filtering out resumes. For the most part, I agree with him. Since it's hard to find good programmers, false negatives are very costly compared to the cost of a false positive (a wasted interview).

But I have …

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