In instrumental variables (IV) estimation with many instruments, such as judge fixed effects designs, the precision of the jackknife-estimated first stage can vary widely across observations. When such variability exists, we show that the precision of JIVE second-stage estimates is meaningfully improved by shrinking judge propensities towards their conditional means, where the shrinkage factor depends on the precision of the first-stage fitted value. Doing so requires no further assumptions and identifies the same local average treatment effect as the usual (unshrunken) JIVE estimator. We illustrate the precision gains from using a Shrunken JIVE estimator (SJIVE) in an application from the literature studying pre-trial detention of defendants in criminal cases.