Overview  •  Sample Design  •  Data Collection Methodology  •  Questionnaire Development  •  Interviewing  & Data Collection  •  Database Management  •  Statistical Analysis  & Reports  •  Research Registry

Sample Design

SRP staff provide advice on sampling methodology and sample size to meet study objectives and budget.  Services include in-house development of specialized sample frames and consultation with commercial sampling firms to obtain an appropriate sample.  Examples of the types of samples provided include the following:

• Random digit dialing (RDD) samples
  
  Particularly suited for telephone surveys of the general population, computer-generated telephone numbers are used to target specific geographic areas, including both listed and unlisted phone numbers. RDD sampling for any region of the United States is available.

• Targeted/listed samples
  
  These samples are used to reach specific subgroups or rare populations. These are useful for telephone recruitment of participants for larger studies. They also are used for supplementing RDD samples with oversamples of rare populations.