To explore the impact of using electronic data in performance management to improve nursing compliance with a protocol.Electronic data is increasingly used to monitor protocol compliance but little is known about the impact on nurses' practice in hospital wards.Seventeen acute hospital nursing staff participated in semi-structured interviews about compliance with an early warning score (EWS) protocol delivered by a bedside electronic handheld device.Before electronic EWS data was used to monitor compliance, staff combined protocol-led actions with clinical judgement. However, some observations were missed to reduce noise and disruption at night. After compliance monitoring was introduced, observations were sometimes covertly omitted using a loophole. Interviewees described a loss of autonomy but acknowledged the EWS system sometimes flagged unexpected patient deterioration.Introducing automated electronic systems to support nursing tasks can decrease nursing burden but remove the ability to record legitimate reasons for missing observations. This can result in covert resistance that could reduce patient safety.Providing the ability to log legitimate reasons for missing observations would allow nurses to balance professional judgement with the use of electronic data in performance management of protocol compliance. This article is protected by copyright. All rights reserved.