AKM: new variance/covariance options (i.e. new Q matrices)

[adamoppenheimer]

Add option to estimate within and between firm variance for AKM and its bias corrections.

[adamoppenheimer]

Another set of options to add for Q matrices:

• cov(alpha_i, alpha_j) for coworkers, to estimate sorting of workers within firms
• cov(psi_j1, psi_j2) for firms that are directly linked by workers, to estimate some sort of network effect of whether firms with similar firm effects are connected

[adamoppenheimer]

Add option to break down Q by each group of a particular category.

E.g. you could specify compute var(psi) but separately by firm quantile, where you don’t include firm quantile as a control variable, but just use it for separating the Q matrix.

[santiagohermo]

These look like useful features. I think it'd also be nice to compute variance components within clusters, such as regions.

[adamoppenheimer]

@santiagohermo what is the difference between your suggestion and the last suggestion I wrote?

Also, the last suggestion I wrote is available in the dev version. If you check here, you can see how to use the updated Q code so that you can get the variance components within a particular category/cluster.

[santiagohermo]

Nice @adamoppenheimer, thanks! The package keeps getting better. I'll take a look at the dev version.