Security is a real problem for US schools, which can either sprawl across several acres or sit in the middle of a busy urban area. Keeping children, especially very young children, on site can be as important as preventing intruders entering unnoticed.
A survey by the National Center for Education Statistics in the US, published in 2007, showed that 85 per cent of schools controlled access to their buildings during school hours: by far the most common security measure in use.
Other frequently used security measures, by between 40-50 per cent of schools, included the control of access to school grounds as well as buildings, a requirement for adults to wear ID cards, and the use of CCTV cameras. Interestingly, 14 per cent of schools classified student uniforms as a security measure, but only 6 per cent of schools required badges or picture IDs to be worn by students. One per cent of schools surveyed had daily metal detector checks.
Most of the other measures in the survey were more concerned with spotting drug issues, so just over one in five schools used random dog sniffs to check for drugs, and 5 per cent of schools performed drug testing on their athletes: 3 per cent of schools tested students participating in wider extra-curricular activities.
Overall, the survey results probably aren't very different from measures taken this side of the Atlantic, except that sniffer dogs are probably less used here and student uniforms are a more common sight, although probably not for security reasons.
John Howson is a director of Education Data Surveys, part of TSL Education.