Policy-changing results or artifacts of big data?

The New York Times article Big Study Links Good Teachers to Lasting Gain covers a research study coming out of Harvard and Columbia on “The Long-Term Impacts of Teachers: Teacher Value-Added and Student Outcomes in Adulthood“. The authors used sophisticated econometric models applied to data from a million students to conclude: “We find that students assigned to higher VA [Value-Added] teachers are more successful in many dimensions. They are more likely to attend college, earn higher salaries, live in better neighborhoods, and save more for retirement. They are also less likely to have children as teenagers.” When I see social scientists using statistical … Continue reading Policy-changing results or artifacts of big data?

SAS On Demand: Enterprise Miner — Update

Following up on my previous posting about using SAS Enterprise Minder via the On Demand platform: From continued communication with experts at SAS, it turns out that with the EM version 5.3, which is the one available through On Demand, there is no way to work (or even access) non-SAS files. Their suggestion solution is to use some other SAS product like SAS BASE, or even SAS JMP (which is available through the On Demand platform) in order to convert your CSV files to SAS data files… From both a pedagogical and practical point of view, I am reluctant to … Continue reading SAS On Demand: Enterprise Miner — Update

Start the Revolution

Variability is a key concept in statistics. The Greek letter Sigma has such importance, that it is probably associated more closely with statistics than with Greek. Yet, if you have a chance to examine the bookshelf of introductory statistics textbooks in a bookstore or the library you will notice that the variability between the zillions of textbooks, whether in engineering, business, or the social sciences, is nearly zero. And I am not only referring to price. I can close my eyes and place a bet on the topics that will show up in the table of contents of any textbook … Continue reading Start the Revolution