Do US State Breach Notification Laws Decrease Firm Data Breaches?

From 2003 to 2018, all 50 states and the District of Columbia enacted breach notification laws (BNLs) mandating that firms suffering data breaches provide timely notification to affected persons and others about breach incidents and mitigation responses. BNLs were supposed to decrease data breaches and develop amarket for data privacywhere firms could strike their preferred balance between data security quality and cost. We find no systemic evidence for either supposition. Results from two-way difference-in-difference analyses indicate no decrease in data breach incident counts or magnitudes after BNLs are enacted. Results also indicate no longer-term decrease in data misuse after breaches. These non-effects appear to be precisely estimated nulls that persist for different firms, time-periods, data-breach types, and BNL types. Apparently inconsistent notification standards and inadequate information dissemination to the public may explain BNL ineffectiveness. An alternative federal regime may address these shortcomings and let a national BNL achieve goals state BNLs have apparently failed to meet.