Get access

Reliability of Height and Weight Measurements Collected by Physical Education Teachers for a School-Based Body Mass Index Surveillance and Screening System


  • This research was supported by the Carol M. White Physical Education for Progress grant. We are very thankful and appreciative for the support provided by Cambridge Public Schools, Maryann Capello, all participating PE teachers, students and their parents, Tufts University School of Medicine faculty: Elena Naumova, Mark Woodin, Anthony Schlaff, and the Institute for Community Health: Dr. Karen Hacker, Dr. Suzanne Mitchell, and student internship program.

Stephanie S. Berkson, Lecturer, (, University of Illinois at Chicago, School of Public Health, Community Health Sciences, Institute for Community Health, 70 E. Brookline Street #3, Boston, MA 02118.


BACKGROUND: To address the obesity epidemic among children and youth, school-based body mass index (BMI) screening and surveillance is proposed or mandated in 30 states. In Cambridge, MA, physical education (PE) teachers are responsible for these measurements. This research reports the reliability of height and weight measures collected by these PE teachers.

METHODS: Using Bland-Altman plots, mean absolute differences, and intraclass correlation coefficients (ICC), we estimated intra- and inter-rater reliability among PE teachers in a controlled setting and PE teacher-vs-expert inter-rater reliability in a natural classroom setting. We also qualitatively assessed barriers to reliability.

RESULTS: For the controlled setting, of 150 measurements, 3 height (2.0%) and 2 weight (1.33%) measurement outliers were detected; intra-rater mean absolute differences for height/weight were 0.52 inches (SD 1.61) and 0.8 lbs (SD 3.2); intra- and inter-rater height/weight ICCs were ≥0.96. For the natural setting, of 105 measurements, 1 weight measurement outlier (0.9%) was detected; PE teacher-vs-expert-rater mean absolute differences for height/weight were 0.22 inches (SD 0.21) and 0.7 lbs (SD 0.8), and ICCs were both 0.99. Equipment deficiencies, data recording issues, and lack of students' preparation were identified as challenges to collecting reliable measurements.

CONCLUSION: According to ICC criteria, reliability of PE teachers' measurements was “excellent.” However, the criteria for mean absolute differences were not consistently met. Results highlight the importance of staff training and data cleaning.