In this issue: Time to replace doctors' judgement with computers.

Informaticians continue to rise to the challenge, set by the English Health Minister, of trying to replace doctors' judgement with computers. This issue describes successes and where there are barriers. However, whilst there is progress this tends to be incremental and there are grand challenges to be overcome before computers can replace clinician. These grand challenges include: (1) improving usability so it is possible to more readily incorporate technology into clinical workflow; (2) rigorous new analytic methods that make use of the mass of available data, 'Big data', to create real-world evidence; (3) faster ways of meeting regulatory and legal requirements including ensuring privacy; (4) provision of reimbursement models to fund innovative technology that can substitute for clinical time and (5) recognition that innovations that improve quality also often increase cost. Informatics more is likely to support and augment clinical decision making rather than replace clinicians.