Body Mass Index (BMI) Measurement in Schools – Safeguard 2

Safeguard 2. Ensure that staff members who measure height and weight have the appropriate expertise and training to obtain accurate and reliable results and minimize the potential for stigmatization.

Accurate measurements are those that correspond to the youth’s actual height and weight, while reliable measurements are those that produce consistent results when they are repeated.1 Measurements are more likely to be accurate and reliable when they are conducted by trained professionals, such as school nurses.2,3 Unfortunately, many schools do not have full-time nurses on campus,4 and many school nurses feel that they cannot add another responsibility to their workload.5 Staff members involved in the program need the appropriate technical training from people who are experienced in conducting height and weight measurements and calculating and interpreting BMI results.6 Conducting repetitive tasks, such as measuring height and weight, can be tedious and may lead an individual to become careless and fail to consistently follow measurement protocols. Quality control checks can be implemented through random visits at measurement sites to oversee the performance of the staff measuring students’ height and weight.

Staff members can ensure that each student takes off his or her shoes and jacket or other heavy clothing items and removes all items from his or her pockets before being weighed.7 Similarly, staff members must make sure that hair styles do not interfere with an accurate measurement of height.7 Each measurement can be taken twice and the youth can be repositioned prior to each measurement.1 If the two measurements do not agree within one-fourth of a pound for weight or one-fourth of an inch for height, then two additional measures can be taken until there is agreement.1,6 Height errors, in particular, reduce the validity of BMI substantially.1

Staff can also get appropriate training to learn how to measure height and weight in a sensitive and caring manner. This training can address procedures to maintain student privacy during measurement,8 increase awareness of groups at increased risk of stigmatization (i.e., larger students, shorter boys, and taller girls), provide information about body size acceptance and the dangers of unhealthy weight control practices, and help staff identify indications of student problems related to weight or body image (e.g., eating disorders).

Staff can be prepared to respond to questions or comments by students. For example, if a student makes a negative comment about his or her own weight, staff members can respond with supportive statements such as, “Kids’ bodies come in lots of different sizes and shapes. If other kids are teasing you about your body, let’s talk and see what we can do about it”.9 Staff members can also respond to questions about what the school will do with the measurement results and referrals.

Resources that can assist with training on height and weight measurement include:

Source: Nihiser AJ, Lee SM, Wechsler H, McKenna M, Odom E, Reinold C, Thompson D, Grummer-Strawn L. Body Mass Index Measurement in Schools. Journal of School Health. 2007; 77:651-671.


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  1. U.S. Department of Health and Human Services, Health Research and Services Administration, Maternal and Child Health Bureau. Growth charts training: accurate weighing and measuring. U.S. Department of Health and Human Services; 2006. Available at:
  2. American Academy of Pediatrics, Committee on School Health. The role of the school nurse in providing school health services. Pediatrics. 2001;108(5):1231-1232.
  3. Ikeda JP, Crawford PB, Woodward-Lopez G. BMI screening in schools: helpful or harmful. Health Educ Res. 2006;21(6):761-769.
  4. Brener ND, Wheeler L, Wolfe LC, Vernon-Smiley M, Caldart-Olson L. Health services: results from the School Health Policies and Programs Study 2006. J Sch Health. 2007;77(8):464-485.
  5. University of Arkansas for Medical Sciences, College of Public Health. Year two evaluation: Arkansas Act 1220 of 2003 to combat childhood obesity. University of Arkansas for Medical Sciences; 2006. Available at:
  6. Gance-Cleveland B, Bushmiaer M. Arkansas school nurses’ role in statewide assessment of body mass index to screen for overweight children and adolescents. J Sch Nurs. 2005;21(2):64-69.
  7. Ikeda JP, Crawford PB. Guidelines for collecting heights and weights on children and adolescents in the school setting. University of California Berkeley, Center for Weight and Health; 2005. Available at:
  8. Haller EC, Petersmarck K, Warber JP, editors. The role of Michigan schools in promoting healthy weight. Lansing, MI: Michigan Department of Education; 2001. Available at:
  9. Crawford PB, Woodward-Lopez G, Ikeda JP. Weighing the risks and benefits of BMI reporting in the school setting. Center for Weight and Health; 2006. Available at: