OFSTED grade schools having once inspected them and grade them under one of four rankings. Grade one, or outstanding, is the highest score that can be achieved. These schools are exempt from routine inspections, unless they re nurseries, special schools or Pupil Referral Units (PRUs). Grade 2, or good, receive a one-day short inspection every three years, or a full inspection if the school’s performance has changed dramatically. Grade 3, or requires improvement, is awarded to schools that will require another full OFSTED inspection within two years in order to monitor their progress. Lastly, schools can be awarded a grade four, which means they re defined as inadequate . Schools graded as inadequate will receive regular OFSTED inspections.