Over on SSRN, Todd Peppers, Mike Giles, and Bridget Tanier-Parkins have posted "The Hiring and Utilization of Federal District Court Law Clerks." From the abstract:
Using original survey data of 311 active and senior federal district court judges, we take the first step in delineating the institutional rules and norms surrounding the selection and use of law clerks in the federal district courts. Our findings reveal that federal district court judges assign their law clerks a number of substantive job duties, findings which raise important new questions about law clerk influence in the lower federal courts.
Among their interesting findings: District court judges place an applicant's personality high on the list of desiderata when selecting clerks. ATSRTWT.