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

More documents

Recommendations

Info

lation 6 to 15 years of age were derivedfrom the screening interview. Statisticsfor the population 16 years old andolder come from both the screeningand detailed interviews. Estimates thatcome from the screening sample arepresented in Appendix B.A. Screening SampleEvery interviewed person inthe screening sample receiveda screening weight that was theproduct of the following factors:1. Base Weight. The base weightis the inverse of the household’sprobability of selection.2 Household NoninterviewAdjustment. The noninterviewadjustment inflates the weightassigned to interiewed householdsto account for householdseligible for interview butfor which no interview wasobtained.3. First-Stage Adjustment. The824 areas designated for oursamples were selected from2,025 such areas of the UnitedStates. Some sample areasrepresent only themselves andare referred to as self-representing.The remaining areasrepresent other areas similarin selected characteristics andare thus designated non-selfrepresenting.The first-stagefactor reduces the component ofvariation arising from samplingthe non-self-representing areas.4. Second-Stage Adjustment. Thisadjustment brings the estimatesof the total population intoagreement with census-basedestimates of the civilian noninstitutionalizedand nonbarrackmilitary populations for eachstate.B. Sportspersons SampleEvery interviewed person in thesportspersons detailed samplereceived a weight that was theproduct of the following factors:1. Screening Weight. This is theperson’s final weight from thescreening sample.2. Sportspersons Stratum Adjustment.This factor inflates theweights of persons selected forthe detailed sample to accountfor the subsampling done withineach sportsperson stratum.3. Sportspersons NoninterviewAdjustment. This factor adjuststhe weights of the interviewedsportspersons to account forsportspersons selected for thedetailed sample for whomno interview was obtained. Aperson was considered a noninterviewif he or she was notinterviewed in the third wave ofinterviewing.4. Sportspersons Ratio AdjustmentFactor. This is a ratio adjustmentof the detailed sample tothe screening sample withinthe sportspersons samplingstratum. This adjustment bringsthe population estimates ofpersons aged 16 years old andolder from the detailed sampleinto agreement with the sameestimates from the screeningsample, which was a muchlarger sample.C. Wildlife-Watchers SampleEvery interviewed person in thewildlife-watchers detailed samplereceived a weight that was theproduct of the following factors:1. Screening Weight. This is theperson’s final weight from thescreening sample.2. Wildlife-Watchers StratumAdjustment. This factor inflatesthe weights of persons selectedfor the detailed sample toaccount for the subsamplingdone within each wildlifewatcher stratum.3. Wildlife-Watchers NoninterviewAdjustment. This factor adjuststhe weights of the interviewedwildlife-watching participantsto account for wildlife watchersselected for the detailed samplefor which no interview wasobtained. A person was considereda noninterview if he or shewas not interviewed in the thirdwave of interviewing.4. Wildlife-Watchers Ratio AdjustmentFactor. This is a ratioadjustment of the detailedsample to the screening samplewithin wildlife-watcherssampling strata. This adjustmentbrings the population estimatesof persons aged 16 years oldand older from the detailedsample into agreement withthe same estimates from thescreening sample, which was amuch larger sample.ACCURACY OF THE ESTIMATESA sample survey estimate has two typesof error: sampling and nonsampling.The accuracy of an estimate dependson both types of error. The nature ofthe sampling error is known given thesurvey design; the full extent of thenonsampling error is unknown.NONSAMPLING ERRORFor a given estimator, the differencebetween the estimate that would resultif the sample were to include the entirepopulation and the true populationvalue being estimated is known asnonsampling error. There are severalsources of nonsampling error thatmay occur during the development orexecution of the survey. It can occurbecause of circumstances created by theinterviewer, the respondent, the surveyinstrument, or the way the data arecollected and processed. For example,errors could occur because:• The interviewer records the wronganswer, the respondent providesincorrect information, the respondentestimates the requestedinformation, or an unclear surveyquestion is misunderstood by therespondent (measurement error).• Some individuals who should havebeen included in the survey framewere missed (coverage error).122 2011 National Survey of Fishing, Hunting, and Wildlife-Associated Recreation U.S. Fish and Wildlife Service and U.S. Census Bureau
• Responses are not collected fromall those in the sample or therespondent is unwilling to provideinformation (nonresponse error).• Values are estimated impreciselyfor missing data (imputation error).• Forms may be lost; data maybe incorrectly keyed, coded, orrecoded, etc. (processing error).The Census Bureau employs qualitycontrol procedures throughout theproduction process, including theoverall design of surveys, the wordingof questions, the review of the workof interviewers and coders, and thestatistical review of reports to minimizethese errors. Two types of nonsamplingerror that can be examined to a limitedextent are nonresponse and undercoverage.Nonresponse. The effect of nonresponsecannot be measured directly, butone indication of its potential effect isthe nonresponse rate. For the FHWARscreener interview in the United States,the household-level nonresponse ratewas 29 percent. The person-levelnonresponse rate for the detailedsportsperson interview in the UnitedStates was an additional 31 percentand for the wildlife watchers it was33 percent. Since the screener nonresponserate is a household-level rateand the detailed interview nonresponserate is a person-level rate, we cannotcombine these rates to derive an overallnonresponse rate. Since it is unlikelythe nonresponding households to theFHWAR have the same number ofpersons as the households successfullyinterviewed, combining these rateswould result in an overestimate of the“true” person-level overall nonresponserate for the detailed interviews.Coverage. Overall screener undercoverageis estimated to be about 13percent. Ratio estimation to independentpopulation controls, as describedpreviously, partially corrects for thebias due to survey undercoverage.However, biases exist in the estimatesto the extent that missed persons inmissed households or missed persons ininterviewed households have differentcharacteristics from those of interviewedpersons in the same age group.Comparability of Data. Data obtainedfrom the 2011 FHWAR and othersources are not entirely comparable.This results from differences in interviewertraining and experience and indiffering survey processes. This is anexample of nonsampling variabilitynot reflected in the standard errors.Therefore, caution should be usedwhen comparing results from differentsources. (See Appendix C.)A Nonsampling Error Warning. Sincethe full extent of the nonsampling erroris unknown, one should be particularlycareful when interpreting results basedon small differences between estimates.The Census Bureau recommends thatdata users incorporate informationabout nonsampling errors into theiranalyses, as nonsampling error couldimpact the conclusions drawn fromthe results. Caution should also beused when interpreting results basedon a relatively small number of cases.Summary measures (such as mediansand percentage distributions) probablydo not reveal useful information whencomputed on a subpopulation smallerthan 90,000 for screener data, 100,000for the detailed sportsperson data, and235,000 for the wildlife-watchers data.SAMPLING ERRORSince the FHWAR estimates comefrom a sample, they may differ fromfigures from an enumeration of theentire population using the same questionnaires,instructions, and enumerators.For a given estimator, the differencebetween an estimate based on asample and the estimate that wouldresult if the sample were to include theentire population is known as samplingerror. Standard errors, as calculated bymethods described in “Standard Errorsand Their Use,” are primarily measuresof the magnitude of sampling error.However, they may include some nonsamplingerror.Standard Errors and Their Use. Thesample estimate and its standard errorenable one to construct a confidenceinterval. A confidence interval is arange that has a known probabilityof including the average result of allpossible samples. For example, if allpossible samples were surveyed underessentially the same general conditionsand using the same sample design, andif an estimate and its standard errorwere calculated from each sample, thenapproximately 95 percent of the intervalsfrom 1.96 standard errors belowthe estimate to 1.96 standard errorsabove the estimate would include theaverage result of all possible samples.A particular confidence interval may ormay not contain the average estimatederived from all possible samples.However, one can say with specifiedconfidence that the interval includesthe average estimate calculated fromall possible samples. Standard errorsmay also be used to perform hypothesistesting, a procedure for distinguishingbetween population parameters usingsample estimates. The most commontype of hypothesis is that the populationparameters are different. An examplewould be comparing the proportion ofanglers to the proportion of hunters.Tests may be performed at variouslevels of significance. A significancelevel is the probability of concludingthat the characteristics are differentwhen, in fact, they are the same. Forexample, to conclude that two characteristicsare different at the 0.05 level ofsignificance, the absolute value of theestimated difference between characteristicsmust be greater than or equalto 1.96 times the standard error of thedifference. This report uses 95-percentconfidence intervals and 0.05 level ofsignificance to determine statisticalvalidity. Consult standard statisticaltextbooks for alternative criteria.Estimating Standard Errors. TheCensus Bureau uses replicationmethods to estimate the standard errorsof FHWAR estimates. These methodsprimarily measure the magnitude ofsampling error. However, they domeasure some effects of nonsamplingerror as well. They do not measuresystematic biases in the data associatedwith nonsampling error. Bias isthe average over all possible samplesof the differences between the sampleestimates and the true value.Generalized Variance Parameters.While it is possible to compute andpresent an estimate of the standarderror based on the survey data for eachestimate in a report, there are a numberof reasons why this is not done. Apresentation of the individual standarderrors would be of limited use, sinceone could not possibly predict all ofthe combinations of results that maybe of interest to data users. Additionally,data users have access to FHWARmicrodata files, and it is impossible toU.S. Fish and Wildlife Service and U.S. Census Bureau 2011 National Survey of Fishing, Hunting, and Wildlife-Associated Recreation 123
Page 1:
U.S. Fish & Wildlife Service2011Nat
Page 4 and 5:
Economics and StatisticsAdministrat
Page 6 and 7:
List of TablesFishing and Hunting1.
Page 8 and 9:
ForewordWhen I was growing up, it w
Page 11 and 12:
Highlights
Page 13 and 14:
watching (observing, photographing,
Page 15 and 16:
Expenditures for Wildlife-Related R
Page 17 and 18:
Fishing
Page 19 and 20:
Fishing ExpendituresAnglers spent $
Page 21 and 22:
Freshwater Fishing ExpendituresAngl
Page 23 and 24:
pike, pickerel, and muskie, as well
Page 25 and 26:
Sex and Age of AnglersAlthough more
Page 27 and 28:
The majority of anglers had househo
Page 29:
2001-2011 Fishing Participants, Day
Page 32 and 33:
Hunting HighlightsIn 2011, 13.7 mil
Page 34 and 35:
Big Game HuntingIn 2011, a majority
Page 36 and 37:
Days per hunterTrips per hunterTrip
Page 38 and 39:
Hunting on Public and PrivateLandsm
Page 40 and 41:
Large MSA25%Medium MSA17%Percent of
Page 42 and 43:
Hispanics, who represent a growingp
Page 45 and 46:
Wildlife WatchingU.S. Fish and Wild
Page 47 and 48:
Wildlife-Watching ExpendituresThirt
Page 49 and 50:
Wildlife Fed, Observed, orPhotograp
Page 51 and 52:
Metropolitan and NonmetropolitanAro
Page 53 and 54:
Education, Race, and Ethnicity ofAr
Page 55 and 56:
Away-From-Home Participantsby Type
Page 57 and 58:
Away-From-Home WildlifeWatchers by
Page 59 and 60:
Metropolitan and NonmetropolitanAwa
Page 61 and 62:
2001-2011 Comparison of Wildlife-Wa
Page 63:
2006-2011 Wildlife-Watching Partici
Page 66 and 67:
Guide to Statistical TablesPurpose
Page 68 and 69:
Table 3. Freshwater Anglers and Day
Page 70 and 71:
Table 7. Hunters and Days of Huntin
Page 72 and 73:
Table 8. Selected Characteristics o
Page 74 and 75:
Table 9. Selected Characteristics o
Page 76 and 77:
Table 10. Selected Characteristics
Page 78 and 79:
Table 12. Expenditures for Fishing:
Page 80 and 81:
Table 14. Trip and Equipment Expend
Page 82 and 83: Table 16. Trip and Equipment Expend
Page 88 and 89: Table 22. Special Equipment Expendi
Page 90 and 91: Table 25. Freshwater Anglers and Da
Page 92 and 93: Table 29. Hunters and Days of Hunti
Page 94 and 95: Table 33. Hunters Preparing for Hun
Page 96 and 97: Table 37. Participation in Wildlife
Page 98 and 99: Table 40. Expenditures for Wildlife
Page 100 and 101: Table 41. Selected Characteristics
Page 102 and 103: Table 42. Selected Characteristics
Page 104 and 105: Table 46. Total Wildlife-Related Pa
Page 106 and 107: Appendix A.DefinitionsAnnual househ
Page 108 and 109: State governments (such as State pa
Page 110 and 111: Appendix B.2010 Participation of 6-
Page 112 and 113: Table B-4. Most Recent Year of Fish
Page 114 and 115: Table B-7. Selected Characteristics
Page 116 and 117: Table B-9. Participation by 6-to-15
Page 118 and 119: Appendix C.Significant Methodologic
Page 120 and 121: Table C-1. Major Characteristics of
Page 122 and 123: Table C-2. Anglers and Hunters by C
Page 124 and 125: household income in the 2001Survey.
Page 126 and 127: Table C-4. Comparison of Major Find
Page 128 and 129: Table C-5. Anglers and Hunters by C
Page 130 and 131: Appendix D.Sample Design and Statis
Page 134 and 135: compute in advance the standard err
Page 136 and 137: Illustration of the Computation of
Page 138 and 139: Table D-2. Approximate Standard Err
Page 140 and 141: Table D-4. Approximate Standard Err
Page 143: U.S. Department of the InteriorU.S.
show all

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

Create successful ePaper yourself

Delete template?

Save as template?