Topics
A to Z
Data &
 Statistics
Forms &
Publications
News &
Advisories
Licensing &
Certification
Rules &
Regulations
Public Health
Directory
Print this Article   Bookmark and Share
OHT 2004 Survey Methodology
Introduction
Sampling and Response Rates
District and School Reports
Weighting Adjustment
State and County Reports
More Detailed Information

Introduction

The Oregon Healthy Teens Survey (OHT) is the one state-sponsored survey designed to monitor the health and well being of adolescents. 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 and the Oregon Progress Board. The survey instruments have been revised annually since 1991 and this year consisted of one version for 11th grade students, containing 299 separate response items, and two versions for 8th grade students, containing either 243 or 266 response items with 64% of the items common to both forms.
Back to the Top

Sampling and Response Rates

This year’s survey was conducted among approximately one third of all 8th and 11th graders statewide. Surveyed schools were selected through three processes: As part of a statewide random sample, as part of the Oregon Research Institute (ORI) Tobacco Prevention evaluation (there was some overlap between these first two groups) or as a volunteer school. The surveys were conducted by either ORI, for schools under their funding, or by a private contractor to DHS, who instructed classroom teachers in proctoring the survey. Surveys were returned from 24,425 students, representing an overall response rate of 79.5% of those sampled. Of these, 597 (2.5%) were excluded based on validity criteria relating to inconsistent and/or dubious response patterns among related items. An additional 1,078 (4.4%) were excluded for missing grade or gender information, leaving 22,750 valid surveys, 93.1% of all received. This left the number of valid surveys at 9,247 from 11th grade and 13,503 from 8th grade students, representing 99 high schools and 119 feeder middle schools in 35 counties.
Back to the Top

District and School Reports

Summary and detailed reports were sent to each participating school and district and 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.
Back to the Top

Weighting Adjustment

The surveys from schools that were part of the statewide random sample (11,829 8th graders, 8,386 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) at ± 0.7% for the 8th grade and ± 0.9% for the 11th grade. The exact margin of error for each question is smaller and varies, depending on the percentage estimated for that particular question. The margins of error for county estimates are slightly larger, depending on the numbers of surveys collected in the county, but are generally smaller than ± 5%.
Back to the Top

State and County Reports

OHT county-level and statewide results are available on this website. In order to ensure a representative sample, if a particular county had less than 50 students at a grade level, their results are only reported as a composite measure with neighboring counties. Data collected from volunteer classrooms or volunteer schools were not included in the statewide or county-level reporting.
Back to the Top

More Detailed Information

For more detailed information, you can view the long form report of the 2004 Oregon Healthy Teens methodology.
Back to the Top