{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,15]],"date-time":"2026-10-15T19:39:55Z","timestamp":1792093195411,"version":"4.4.0"},"reference-count":37,"publisher":"Oxford University Press (OUP)","issue":"5","license":[{"start":{"date-parts":[[2025,12,30]],"date-time":"2025-12-30T00:00:00Z","timestamp":1767052800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by-nc\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"published-print":{"date-parts":[[2026,9,8]]},"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:p>We develop a test for instrument strength based on the bias of two-stage least squares (2SLS) that (1) generalizes Stock and Yogo\u2019s and Sanderson and Windmeijer\u2019s tests to be robust to heteroskedasticity and autocorrelation, and (2) extends Montiel Olea and Pflueger\u2019s robust test for models with a single endogenous regressor to multiple endogenous regressors. Our test can be based either on an absolute bias criterion or on the 2SLS bias relative to a worst-case benchmark. We also develop extensions to test whether weak instruments cause bias in individual 2SLS coefficients. In simulations, our test controls size and is powerful, and we provide efficient code packages for its practical implementation. We demonstrate our testing procedures in the context of the estimation of state-dependent fiscal multipliers, following recent leading estimates.<\/jats:p>","DOI":"10.1093\/restud\/rdaf103","type":"journal-article","created":{"date-parts":[[2025,12,20]],"date-time":"2025-12-20T12:55:51Z","timestamp":1766235351000},"page":"3303-3336","source":"Crossref","is-referenced-by-count":7,"title":["A Robust Test for Weak Instruments for 2SLS with Multiple Endogenous Regressors"],"prefix":"10.1093","volume":"93","author":[{"given":"Daniel J","family":"Lewis","sequence":"first","affiliation":[{"name":"University College London , ; CEPR, UK","place":["UK"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Karel","family":"Mertens","sequence":"additional","affiliation":[{"name":"Federal Reserve Bank of Dallas, USA ; CEPR, 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