Data Integrity by Design is the concept that data integrity must be incorporated from the initial planning of a business process through to the implementation, operation, and retirement of computerized systems supporting that business process. It promotes the application of critical thinking to identify how data flows through the business process and to proactively assess and mitigate risks across both the system and data lifecycles. It emphasizes data integrity as foundational to protecting patient safety and product quality. ThisISPE GAMP®RDI Good Practice Guide: Data Integrity by Design supports organizations as they embrace and implement a holistic approach by leveraging data governance and knowledge management activities to drive continual improvement in data integrity. The Guide promotes a patient-centric mindset, focusing resources and management attention on quality best practices that inherently facilitate meeting regulatory compliance requirements. This Guide provides a bridge between the system lifecycle approach defined in ISPE GAMP® 5: A Risk-Based Approach to Compliant GxP Computerized Systems, and the data lifecycle approach in the ISPE GAMP®Guide: Records and Data Integrity. Data integrity can only be achieved when both lifecycle approaches are adopted, understood, and actively managed. Several new areas are covered in this Guide. One such topic is Knowledge Management (KM), which can be considered the link between data governance and quality risk management. KM enables organizations to make decisions more efficiently and encourages an organizational culture of learning. Many instrument devices such as filter integrity testers and pH meters have moved from a simple display of the measured value to temporarily storing electronic records. This evolution has resulted in increasing regulatory awareness of the data integrity risk posed by such devices lacking the sophisticated technical controls inherent in larger computerized systems. The ISPE GAMP®RDI Good Practice Guide: Data Integrity by Design offers a pragmatic, practical approach to the identification and remediation of the risks, and endorses the adoption of working practices to protect and review the electronic records. In an industry first, members of the Computer Software Assurance (CSA) team (responsible for working with the FDA to develop the draft guidance on this topic) have collaborated closely with ISPE GAMP® subject matter experts to create an appendix to the ISPE GAMP®RDI Good Practice Guide: Data Integrity by Design. This appendix details the key concepts of CSA and provides illustrative case studies of its application. This Guide is positioned under the ISPE GAMP®Guide: Records and Data Integrity and replaces and significantly expands upon the ISPE GAMP® Good Practice Guide: Electronic Data Archiving from 2007.