[en] An evaluation is presented of Licensee Event Reports (LERs) pertaining to control rods and drive mechanisms (CRDMs). The purpose of this study was to extract CRDM data from the LERs, to put the data in a form suitable for future statistical analyses, to summarize and categorize the data, and to estimate failure rates that can be used as a comparison with other failure rates used in nuclear plant risk assessments. These failure rates were estimated for both failures and faults; that is, failures plus command faults