Friday, March 25, 2016

When You Don't Have A Good Control Group, Just Make One Up!

OK, maybe I'm exaggerating a little bit. Synthetic controls methods are actually really similar to the typical differences in differences approach except that more weight is given to "untreated" observations that are more similar to the "treated" observations in the pre-treatment period. You can read more about this intuition here, but even cooler--you can download a STATA program that automates the process of running multiple synthetic control estimations. It even generates visualizations of the results!

And now you're ready. All you need to do now is find interesting policy changes enacted in different states at different times. Stop reading this blog and go read the newspaper!

PS
UConn people: David Simon is our resident expert on synthetic control methods.

Saturday, March 19, 2016

An Oldie But Goodie: What Are We Weighting For?

I have recently been struggling with deciding how to use weights in a new project. Sometimes this is straightforward (when using IPUMS data for the 1% sample, use the variable perwt). Sometimes, however, data sets come with multiple weights or you might have to create your own. Weights usually matter for when creating tables of descriptive statistics, but often they do not matter when running regressions. Of course, whether we should use weights should depend on how those weights were created. But before spending too much time reading your data's codebook, it is useful to think about why anyone would want to use weights--ever. For insights, have a look at this summary of the paper, "What are we weighting for?" written by Gary Salon, Steven Haider, and Jeffrey Wooldridge.



Sunday, March 6, 2016

From Student to Scholar

This week, students in my labor class are writing proposals for papers due at the end of the semester. This is kind of a big deal since, hopefully, these papers will turn into "third year papers" which (if they're good) will become chapters of their dissertations. It's been quite something to see students go from a broad interest in a topic to a specific question to a specific answerable question to a specific answerable question that hasn't already been answered. I'm reminded that this stuff is hard! But it's so much fun to see them zero in on a topic that they're excited about! Especially when it comes after a long struggle.

In honor of these students, I thought I'd share some of my favorite pieces of advice on how to go from student to scholar. One piece of advice: Don't be boring. Another: Look for ideas in the world, not in journals. But I actually found my favorite piece of advice in a CSWEP newsletter interview of Anna Mikusheva. She writes,

"The main advice is trivial: always work on something. If you have not found a big, exciting project to work on, work on something smaller—a big project will eventually come your way. If you don’t have even a small project, work out some missing details of a paper you’ve recently read or seen presented, and/or try to answer questions that have arisen during the last seminar you attended. Your big idea will come once you have realized enough small projects." 

She also recommends ambition and patience. I would also add that talking about your ideas to people, especially smart people but really anybody who will listen, can be so helpful!