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CTEPP STANDARD OPERATING PROCEDURE FOR SAMPLE SELECTION (SOP-1.10)
WARNING! DATA USE RESTRICTIONS
Read Carefully Before Using
The EPA does all it can to ensure that the identity of survey participants cannot be disclosed. All direct identifiers, as well as any characteristics that might lead to identifications, are omitted from the data. Any intentional identification or disclosure of a person or establishment violates the assurances of confidentiality given to the providers of the information. Therefore, users will (1) use the data in this study for statistical reporting and analysis only; (2) make no use of the identity of any person or establishment discovered inadvertently and will advise the HEDS Administrator of any such discovery; (3) will not link this data with individually identifiable data from other EPA or non-EPA data.
By using the data you signify your agreement to comply with the above-stated statutorily based requirements.
CTEPP STANDARD OPERATING PROCEDURE FOR SAMPLE SELECTION (SOP-1.10).
The CTEPP study is the largest aggregate exposure study of preschool children (ages 2 to 5 years) conducted in the United States. The CTEPP study was designed in part to fill in critical data gaps on young children’s exposures to pesticides in response to the Food Quality Protection Act (FQPA) of 1996.
The procedures for selecting CTEPP study subjects are described in the SOP. The primary, county-level stratification is by region and urbanicity. Six sample counties in each of the two states (North Carolina and Ohio) are selected using stratified random sampling and reflect three distinct geographical areas in each state. Within each of the two states, the samples are further stratified according to urbanicity and family income. The urbanicity stratification is imposed at the first stage of selection by classifying counties as predominantly urban or predominantly rural. Income stratification is performed at subsequent stages of selection for the two sample components, which distinguishes between low-income and mid- to high-income households/daycare centers.
In the daycare sample component, all eligible daycare centers in the six selected counties are identified. During the second-stage sampling frame, these centers are divided into two income strata. From these strata a random sample of targeted centers and a random sample of eligible children within each participating center are selected. In the telephone sample component, a random sample of telephone numbers is selected using list-assisted telephone sampling techniques in the six counties in each state. The anticipated sample size is 128 children in each state, with half (64) from the daycare center sample (children who attend daycare) and the other half (64) from the telephone sample (children who do not attend daycare). This dual frame approach provides maximum coverage for the target population.
In summary, the design simplifies the sampling frame construction and sample selection process. In addition, it allows the project to concentrate recruitment efforts in the selected counties so project resources can be more efficiently used to maximize response rates.
NORTH CAROLINA STUDY DIRECTORY
COMPLETE DOCUMENT (PDF,22 pp, 865 KB, about PDF)
OHIO STUDY DIRECTORY