A senior house officer (SHO) is a non-consultant hospital doctor in the Republic of Ireland. SHOs are supervised in their work by consultants and registrars. In training posts these registrars and consultants oversee training and are usually their designated clinical supervisors. The same structure to junior doctor grades also applied previously in the National Health Service in the UK, and informal use of the term persists there. Irish usage NCHD grades in order, from most junior to most senior: Intern — (post-graduate year 1) Senior house officer — (PGY ≥ 2) Registrar — (PGY ≥ 3) Specialist registrar — (PGY ≥ 4) Fellow (PGY variable) In Ireland, physicians typically spend one year as an intern, before becoming a Senior House Officer (SHO). Most doctors spend between 2–4 years working as an SHO. Advancing to registrar level is dependent on experience and aptitude within a specialty; in most cases, becoming a registrar depends primarily on having successfully passed postgraduate examinations such as MRCP/MRCS, although this is not a strict requirement. Most doctors work at registrar level for 1–3 years before being accepted onto a training programme in a particular subspecialty (e.g. Cardiology), after which time, they are known as SpRs (Specialist Registrars). SpR programmes typically last for between 3–6 years. On completion of an SpR programme, doctors are eligible to apply for consultant positions, although the majority opt to undertake 1–2 years of fellowship training – often abroad – prior to appointment at consultant level. Former UK usage Since the introduction of Modernising Medical Careers (MMC), grades in the UK differ from those in the Republic of Ireland. British postgraduate training Before MMC, physicians applied for SHO posts after completing their mandatory pre-registration house officer (PRHO) year after qualifying from medical school. They would typically work as an SHO for 2–3 years, or occasionally longer, before going on to a certain subspeciality where they would take up a specialist registrar post to train as a specialist in that particular field. To qualify for these, SHOs had to be in posts approved by a regional postgraduate dean, as well as passing postgraduate exams (such as the Membership of the Royal College of Physicians, MRCP). SHO jobs typically lasted four or six months in various departments and were often provided in one- or two-year rotations. Modernising medical careers In 2002, the Department of Health announced reforms in the training of newly qualified doctors