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2007 Survey Methodology
 

Introduction

The Oregon Healthy Teens Survey (OHT) is the one state-sponsored survey designed to monitor the health and well being of adolescents. This survey reflects the information needs of state agencies and local groups as well as the National Cancer Institute (NCI) funded statewide tobacco prevention evaluation study. An anonymous and voluntary research-based survey, the OHT is designed and administered through a collaborative group of Oregon state agencies including the Department of Human Services, the Department of Education, the Governor's Commission on Juvenile Justice, the Commission on Children and Families, the Oregon Progress Board and the Oregon Research Institute. State and local agencies depend on OHT to assess youth needs, develop comprehensive plans and prevention programs, solicit funding and measure outcomes. This year's surveys consisted of one version for 8th and one version for 11th graders, containing 178 and 217 separate response items, respectively.

 

Students Surveyed and Response Rates

This year's survey was conducted among over four in ten of all 8th and 11th graders statewide. Surveyed schools were selected through four processes: As part of a statewide random sample, as a Coordinated School Health (CSH) school, as part of the Oregon Research Institute (ORI) Prevention evaluation (there was some overlap between these three groups) or as a volunteer school. The surveys were conducted by a private contractor to DHS, who instructed classroom teachers in proctoring the survey. Surveys were returned from over 30,000 students, representing an overall response rate of 85.8% of those sampled. Of these, 5.2% were excluded based on validity criteria relating to inconsistent or dubious response patterns. 0.3% were excluded based on both inconsistent and dubious responses. Another 2.4% were excluded solely for missing grade or gender information. 0.1% were excluded due to excessive illegal or multiple marks. 0.7% were excluded because of a visually suspicious answer sheet, leaving 28,100 valid surveys (91.4% of the total received), with 15,161 from 8th grade and 11,287 from 11th grade in 33 counties. There was no data collected at all from Josephine, Lake, and Wallowa counties.

 

District and School Reports

Summary and detailed reports were sent to each participating school and district. These reports are available from the school district. Caution should be used when interpreting percentages based on a small number of respondents. Further, the schools were not selected to provide a reliable estimate for an individual district so caution should be used when combining school data within a district. No personally identifiable information is available because the survey was anonymous. To further protect confidentiality, reports were not broken down by gender if there were fewer than 10 males and 10 females in the school's valid sample. School-specific reports used simple unweighted counts and percents.

 

Weighting Adjustment

The surveys from schools that were part of the statewide random sample (9,535 8th graders, 6,189 11th graders) are weighted, based on district size information, to be representative of all 8th or 11th grade students within a particular county or the state. The published reports for counties and states include weighted percentages for accurate prevalence estimates, but often also include unweighted counts so readers know how many surveys make up each response. Because of the weighting, any percentage recalculation based on the unweighted counts will differ slightly from the published percentages. The published percentages accurately represent county and state prevalence with an overall statewide margin of error (at 95% confidence interval) of approximately ±0.9% for the 8th grade and ±1.2% for the 11th grade. The maximum margin of error occurs with prevalence estimates at or near the 50% level. The exact margin of error for each question is smaller and varies, depending on the percentage estimated for that particular question.

 

More Detailed Information

For more detailed information, you can view the long form report (pdf) of the 2005 Oregon Healthy Teens methodology.