45 CFR § 1356.84 - Sampling.
(a) The State agency may collect and report the information required in section 1356.83(e) of this part on a sample of the baseline population consistent with the sampling requirements described in paragraphs (b) and (c) of this section.
(b) The State agency must select the follow-up sample using simple random sampling procedures based on random numbers generated by a computer program, unless ACF approves another sampling procedure. The sampling universe consists of youth in the baseline population consistent with 45 CFR 1356.81(b) who participated in the State agency's data collection at age 17.
(c) The sample size is based on the number of youth in the baseline population who participated in the State agency's data collection at age 17.
(1) If the number of youth in the baseline population who participated in the outcome data collection at age 17 is 5,000 or less, the State agency must calculate the sample size using the formula in appendix C of this part, with the Finite Population Correction (FPC). The State agency must increase the resulting number by 30 percent to allow for attrition, but the sample size may not be larger than the number of youth who participated in data collection at age 17.
(2) If the number of youth in the baseline population who participated in the outcome data collection at age 17 is greater than 5,000, the State agency must calculate the sample size using the formula in appendix C of this part, without the FPC. The State agency must increase the resulting number by 30 percent to allow for attrition, but the sample size must not be larger than the number of youth who participated in data collection at age 17.