Abstract Administrative records are increasingly used to identify registered voters who may have moved, with potential movers then sent postcards asking them to confirm their address of registration. It is important to understand how often these registrants did not move, and how often such an error is not corrected by the postcard confirmation process, because uncorrected errors make it more difficult for a registrant to subsequently vote. While federal privacy protections generally prevent researchers from observing the data necessary to estimate these quantities, we are able to study this p...