School-based survey participation: oral health and BMI survey of Ohio third graders.

During the 2009-2010 school year, the Ohio Department of Health conducted a statewide oral health and body mass index (BMI) screening survey among 3rd grade children. This marked the fifth school-based survey regarding the oral health of Ohio children since 1987. At 50 %, the participation rate of the 2009-2010 oral health and BMI survey was at the lowest level ever experienced. This study aimed to identify the factors associated with participation rates in a school-based survey. A stratified, random sample of 377 schools was drawn from the list of 1,742 Ohio public elementary schools with third grade students. All third grade children in the sampled schools with parent or guardian consent received an oral health screening and height/weight measurement by trained health professionals. Participation rates at the school level were then combined with data on school characteristics and survey implementation. Predictors of school form return, participation, and refusal rates were assessed by generalized linear modeling (GLM). High student mobility and larger school size were associated with lower form return (p = 0.000 and p = 0.001, respectively) and lower participation rates (p = 0.000 and p = 0.005, respectively). Surveying in the fall or spring (as opposed to winter) significantly decreased form return (p = 0.001 and p = 0.016, respectively) and participation rates (p = 0.008 and p = 0.002, respectively), while being surveyed by internal staff (versus external screeners) significantly increased form return (p = 0.003) and participation rates (p = 0.001). Efforts to increase participation should focus more on schools with higher student mobility and larger size. Additionally, participation could be improved by using internal staff and surveying during winter.