National Survey of Fishing, Hunting, and Wildlife ... - All About Birds

Appendix D.Sample Design and Statistical AccuracyThis appendix is presented in two parts.The first part is the U.S. Census BureauSource and Accuracy Statement. Thisstatement describes the samplingdesign for the 2011 Survey andhighlights the steps taken to produceestimates from the completed questionnaires.The statement explains theuse of standard errors and confidenceintervals. It also provides comprehensiveinformation about errors characteristicof surveys and formulas andparameters to calculate an approximatestandard error or confidence interval foreach number published in this report.The second part, Tables D-1 to D-5,reports approximate standard errorsand 95-percent confidence intervalsfor selected measures of participationand expenditures for wildlife-relatedrecreation.Source and Accuracy Statement forthe 2011 National Survey of Fishing,Hunting, and Wildlife-AssociatedRecreationSOURCE OF DATAThe estimates in this report are basedon data collected in the 2011 NationalSurvey of Fishing, Hunting, and Wildlife-AssociatedRecreation (FHWAR)conducted by the Census Bureau andsponsored by the U.S. Fish and WildlifeService.The eligible universe for the FHWARis the civilian noninstitutionalized andnonbarrack military population livingin the United States. The institutionalizedpopulation, which is excludedfrom the population universe, iscomposed primarily of the populationin correctional institutions and nursinghomes (98 percent of the 4 millioninstitutionalized people in Census2010).The 2011 Survey was designed toprovide state-level estimates of thenumber of participants in recreationalhunting and fishing and in wildlifewatching activities (e.g., wildlife observation).Information was collected onthe number of participants, where andhow often they participated, the type ofwildlife encountered, and the amountsof money spent on wildlife-relatedrecreation.The survey was conducted in twostages: an initial screening of householdsto identify likely sportspersonsand wildlife-watching participants anda series of follow-up interviews ofselected persons to collect detailed dataabout their wildlife-related recreationduring 2011.SAMPLE DESIGNThe 2011 FHWAR sample was selectedfrom the Census Bureau’s masteraddress file (MAF).The FHWAR is a multistage probabilitysample, with coverage in all 50states and the District of Columbia. Inthe first stage of the sampling process,primary sampling units (PSUs) areselected for sample. The PSUs aredefined to correspond to the Office ofManagement and Budget definitionsof Core Based Statistical Area definitionsand to improve efficiency infield operations. The United States isdivided into 2,025 PSUs. These PSUsare grouped into 824 strata. Withineach stratum, a single PSU is chosenfor the sample, with its probability ofselection proportional to its populationas of the 2000 decennial census. ThisPSU represents the entire stratum fromwhich it was selected. In the case ofstrata consisting of only one PSU, thePSU is chosen with certainty.Within the selected PSUs, the FHWARsample was selected from the MAF.FHWAR Screening SampleThe total screening sample in theUnited States consisted of 48,600households. Interviewing for the screenwas conducted during April, May,and June 2011. Due to a high noncontactrate, an additional personal visitscreening interview, for a subsampleof noncontact cases, occurred again inFebruary, March, April, or May 2012.Of all housing units in sample, about42,800 were determined to be eligiblefor interview. Interviewers obtainedinterviews at 30,400 of these units fora national response rate of 71 percent. 1The national weighted response ratewas 77 percent. The interviewers askedscreening questions for all householdmembers 6 years old and older. Noninterviewsoccur when the occupantsare not found at home after repeatedcalls or are unavailable for some otherreason.Data for the FHWAR sportspersonssample and wildlife-watchers samplewere collected in three waves. 2 Thefirst wave started in April 2011, thesecond in September 2011, and thethird in January 2012. In the sportspersonssample, all persons who huntedor fished in 2011 by the time of thescreening interview were interviewed inthe first wave. The remaining sportspersonsin sample were interviewed in thesecond wave. The reference period wasthe preceding 4 months for waves 1 and2. In wave 3, the reference period waseither 4, 8, or 12 months dependingon when the sample person was firstinterviewed.1Response rates are calculated by using APPOR’s RR2formula.2The sample cases selected due to high noncontact rateswere only interviewed once. They received a screenerand, if they had some form of participation, a detailedquestionnaire. These participants did not get three wavesof interviewing. The reference period for these sampledcases was between 13 and 16 months.120 2011 National Survey of Fishing, Hunting, and Wildlife-Associated Recreation U.S. Fish and Wildlife Service and U.S. Census Bureau