Score contribution per author:
α: calibrated so average coauthorship-adjusted count equals average raw count
In models with many instruments, the asymptotic variance of the LIML estimator contains four components. Apart from the traditional variance, one term is due to instrument numerosity, and the last two appear if the model errors are non-normal. For a stylized instrumental variables model, we compute numerical values of these components to uncover how the four components are related to each other in magnitude.