English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Tools annual

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Presents the access of premium content as premium feature

Premium Content

Global: Zendy Plus annual

Global: Zendy Free Plan

In this paper, I show that classic two-stage least squares (2SLS) estimatesare highly unstable with weak instruments. I propose a ridge estimator (ridgeIV) and show that it is asymptotically normal even with weak instruments,whereas 2SLS is severely distorted and un-bounded. I motivate the ridge IVestimator as a convex optimization problem with a GMM objective function and anL2 penalty. I show that ridge IV leads to sizable mean squared error reductionstheoretically and validate these results in a simulation study inspired by datadesigns of papers published in the American Economic Review.

Ridge regularization for Mean Squared Error Reduction in Regression with Weak Instruments