The rapid evolution of health information technology (IT) and drive towards a fully digital healthcare system is a laudable and compelling aspiration that has the undoubted potential to improve the effectiveness, efficiency and experience of care. Whilst health IT has the promise to solve many of the challenges facing healthcare there is a paucity of high-quality evidence to thoroughly evaluate its successes and failures, nor fully identify the very real and often unexpected risks and challenges that come hand-in-hand with potential opportunities and benefits. This thesis therefore seeks to systematically investigate the influence of health IT on the three core facets of healthcare quality in secondary care - effectiveness, safety and experience. An introduction to the current landscape and strategies for the evaluation of health IT is presented to provide context. Following this a number of linked studies undertake to evaluate the current impact of health IT on quality in secondary care. Examinations of the impact of organisational digital maturity on clinical outcomes, stakeholder experience and regulatory judgements of quality are presented. These are followed by an evaluation of nationally reported patient safety incidents related to health IT, and finally a chapter that seeks to define an emerging threat to patient safety - cybersecurity and digital resilience - and identify linked research, practice and policy priorities. The final part of the thesis focuses on a single technology - mobile computing - and undertakes a detailed examination of its current impact on communication and teamwork through a systematic review, followed by an exploration of multi-professional perspectives on moving towards a 'mobile-first' culture of work within the hospital setting. The thesis concludes by highlighting outstanding challenges and identifying future implications for research, day-to-day practice and health policy. The next decade will see fundamental change in all aspects of healthcare driven by new digital technologies. This exciting future must however be viewed with cautious scepticism, an acknowledgement that new technology in isolation cannot bridge the quality and cost-effectiveness chasm, and awareness that technology may also be a new source of potential harm which must be understood, measured and mitigated. There is a requirement for all new technology to be unequivocally backed by high-quality robust evidence and regulated and evaluated in a pragmatic yet comprehensive manner.