All participants included in AI-SUPERPFP lived on or within 20 miles of their reservations at time of sampling (1997). Stratified random sampling procedures were used, with strata defined by tribe, gender, and age. Official enumerations of tribal members known as tribal rolls were used to define the target population. Records were selected randomly from these rolls for inclusion in replicates, which were then released as needed to allow approximately 1,500 completed interviews per tribe. In the SW and NP respectively, 46.6% and 39.2% of persons on tribal rolls lived on or near their reservations; of those located and found eligible, 76.8% in the NP (N=1,638) and 73.7% in the SW (N=1,446) participated. Sample weights accounted for differential selection probabilities across strata and for varying rates of non-response by strata. AI-SUPERPFP methods are described in greater detail elsewhere [10].
