Ọzọkwa nkọwa

Ngalaba a na-iji ike mee ka a kwuru okwu ya, kama na-agụ dị ka a kọrọ.

• Okwu Mmalite (Nkebi 3.1)

Ọtụtụ n'ime isiokwu n'isiokwu a nakwa na e kwughachiri na-adịbeghị anya Presidential Adresị na American Association of Public Opinion Research (AAPOR), dị ka Dillman (2002) , Newport (2011) , Santos (2014) , na Link (2015) .

N'ihi na ihe mere uyen banyere mmepe nke nnyocha e mere nnyocha, gụọ Smith (1976) na Converse (1987) . Maka ozi on echiche nke atọ eras nke nnyocha e mere nnyocha, gụọ Groves (2011) na Dillman, Smyth, and Christian (2008) (nke etịbede elu atọ eras ubé dị iche iche).

A ọnụ ọgụgụ kasị elu n'ime mgbanwe site na mbụ na nke abụọ oge na nnyocha e mere nnyocha bụ Groves and Kahn (1979) , nke na-eme ihe ọmụma zuru ezu isi na-isi tụnyere n'etiti a ihu na ihu na ekwentị nnyocha e mere. Brick and Tucker (2007) afiakde ese akụkọ ihe mere eme mmepe nke random ọbula Ịpị ụfọdụ ụzọ.

Maka ozi otú nnyocha e mere nnyocha agbanweela n'oge gara aga omume mgbanwe otu,-ahụ Tourangeau (2004) , Mitofsky (1989) , na Couper (2011) .

• -Arịọ vs. edebe (Nkebi 3.2)

-Amụ banyere esịtidem na-ekwu site na-arịọ ajụjụ nwere ike ịbụ mfịna mgbe ụfọdụ n'ihi na ndị zaghachirinụ onwe ha amaghị na ha esịtidem na-ekwu. Dị ka ihe atụ, Nisbett and Wilson (1977) nwere ihe magburu onwe akwụkwọ na evocative aha: "Ịgwa ihe karịrị anyị pụrụ ịmata: Okwu Ọnụ akụkọ na iche echiche Filiks." Na akwụkwọ ndị dere ekwubi: "-achị bụ mgbe ụfọdụ (a) amaghị ihe ihe ịdị adị nke a ihe mkpali na ihe na-enwe mmetụta a nzaghachi, (b)-amaghị nke ịdị adị nke omume, na (c) amaghị na ihe mkpali emetụtawo mmeghachi omume. "

N'ihi na arụmụka na-eme nnyocha ga-ahọrọ hụrụ omume ka kọrọ omume ma ọ bụ àgwà, na-ahụ Baumeister, Vohs, and Funder (2007) (akparamaagwa) na Jerolmack and Khan (2014) na-azaghachi (Maynard 2014; Cerulo 2014; Vaisey 2014; Jerolmack and Khan 2014) (sociology). Ihe dị iche n'etiti arịọ na-edebe ihe na-ebilite na akụnụba, ebe na-eme nnyocha na-ekwu banyere kwuru na kpughere mmasị. Dị ka ihe atụ, a na-eme nchọpụta pụrụ ịjụ ajụjụ ma ha na-ahọrọ na-eri ice ude ma ọ bụ aga mgbatị (kwuru, sị mmasị) ma ọ bụ nnyocha nwere ike na-edebe ihe otú mgbe ndị mmadụ na-eri ice ude ma gaa mgbatị (kpughere mmasị). E nwere miri emi skepticism nke ụdị ụfọdụ nke kwuru mmasị data na akụnụba (Hausman 2012) .

A isiokwu ndị a arụmụka bụ na kọrọ omume bụghị mgbe niile ezi. Ma, na-akpaghị aka dere omume nwere ike ịbụ ezi, wee ghara anakọtara na a sample nke mmasị, ma ike ghara ịdị mfe inweta eme nnyocha. N'ihi ya, na ụfọdụ, m na-eche na kọrọ omume ike bara uru. Ọzọkwa, a abụọ isiokwu ndị a arụmụka bụ na akụkọ banyere mmetụta uche, ihe ọmụma, na-atụ anya, na echiche na-adịghị mgbe niile ezi. Ma, ọ bụrụ na ihe ọmụma banyere ihe esịtidem na-ekwu bụ mkpa na-eme nnyocha-ma ọ bụghị iji nyere aka kọwaa ụfọdụ omume ma ọ bụ dị ka ihe na-kọwara-ahụ na-arịọ ga-adaba.

• Total nnyocha e mere njehie (Nkebi 3.3)

N'ihi na akwụkwọ ogologo agwọ ọrịa on ngụkọta e mere na njehie, ahụ Groves et al. (2009) ma ọ bụ Weisberg (2005) . N'ihi na a akụkọ ihe mere eme nke mmepe nke ngụkọta e mere na njehie, ahụ Groves and Lyberg (2010) .

Na okwu nke onodi, a oké iwebata ka okwu nke na-abụghị omume na-abụghị omume echiche ọjọọ bụ National Research Council akụkọ on Nonresponse na Social Science nnyocha ndị e mere: A Research Agenda (2013) . Ọzọ bara uru nnyocha na-nyere site (Groves 2006) . Ọzọkwa, dum pụrụ iche mbipụta nke Journal of Official Statistics, echiche ọha na eze Quarterly, na ndị mere n'ụbọchị ndị American Academy of Political and Social Science e bipụtara na isiokwu nke na-abụghị omume. N'ikpeazụ, e nwere n'ezie ọtụtụ ụzọ dị iche iche nke ịgbakọ nzaghachi ọnụego; ndị a ọ pụrụ na-kọwara n'ụzọ zuru ezu na a akụkọ site American Association of Public Opinion Researchers (AAPOR) (Public Opinion Researchers} 2015) .

The 1936 edemede Digest nghoputa a mụwo n'ụzọ zuru ezu (Bryson 1976; Squire 1988; Cahalan 1989; Lusinchi 2012) . O nwekwara e ji mee ihe dị ilu na aka megide haphazard data collection (Gayo-Avello 2011) . Na 1936, George Gallup eji a ọzọ ọkaibe ụdị ụfọdụ, ma nwee ike na-emepụta ihe ezi atụmatụ e mere na a dị nta sample. Gallup ịga nke ọma n'elu edemede Digest bụ nzọụkwụ dị mkpa na mmepe nke nnyocha e mere nnyocha (Converse 1987, Ch 3; Ohmer 2006, Ch 4; Igo 2008, Ch 3) .

Na okwu nke mmesho, a oké mbụ akụ maka emebe ajụjụ bụ Bradburn, Sudman, and Wansink (2004) . N'ihi na a dị elu ndị ọzọ omume lekwasịrị anya kpọmkwem on àgwà ajụjụ,-ahụ Schuman and Presser (1996) . More on tupu ule ajụjụ bụ dị na Presser and Blair (1994) , Presser et al. (2004) , na Isi nke 8 nke Groves et al. (2009) .

Kpochapụwo, akwụkwọ-ogologo ọgwụgwọ nke ahia-apụ n'etiti nnyocha e mere na-akwụ ụgwọ na e mere na njehie bụ Groves (2004) .

• Onye na-ajụ (Nkebi nke 3.4)

Classic akwụkwọ-ogologo ọgwụgwọ nke ọkọlọtọ nke puru omume ụfọdụ na ọnu bụ Lohr (2009) (ihe mmeghe) na Särndal, Swensson, and Wretman (2003) (elu ndị ọzọ). A kpochapụwo akwụkwọ-ogologo ọgwụgwọ nke post-stratification na yiri ụzọ bụ Särndal and Lundström (2005) . Na ụfọdụ digital afọ ntọala, na-eme nnyocha maara nke a bit banyere ndị na-abụghị ndị zaghachirinụ, nke bụ bụghị mgbe ezi n'oge gara aga. Ụdị dị iche iche nke na-abụghị omume ukpụhọde kwere omume mgbe na-eme nnyocha nwere ihe ọmụma banyere ndị na-abụghị ndị zaghachirinụ (Kalton and Flores-Cervantes 2003; Smith 2011) .

The Xbox amụ Wang et al. (2015) na-eji a Usoro a na-akpọ dọba nlaghachi azụ na post-stratification (MRP, mgbe ụfọdụ, a na-akpọ "Mister P") na-enye ohere na-eme nnyocha na-eme atụmatụ cell pụtara ọbụna mgbe e nwere ọtụtụ, ọtụtụ mkpụrụ ndụ. Ọ bụ ezie na e nwere ụfọdụ arụmụka banyere àgwà nke atụmatụ ndị e mere site na nke a Usoro, o yiri ka a Ná ekwe ebe inyocha. The Usoro mbụ e ji mee ihe na Park, Gelman, and Bafumi (2004) , na e nwere kemgbe ụdi were na arụmụka (Gelman 2007; Lax and Phillips 2009; Pacheco 2011; Buttice and Highton 2013; Toshkov 2015) . N'ihi na ihe mere ka njikọ na onye igwe na cell dabeere igwe na-ahụ Gelman (2007) .

N'ihi na ndị ọzọ bịara ibi nwatakịrị weighting web nnyocha ndị e mere, lee Schonlau et al. (2009) , Valliant and Dever (2011) , na Bethlehem (2010) .

Sample kenha e mere atụmatụ site Rivers (2007) . Bethlehem (2015) rụrụ ụka na arụmọrụ nke sample kenha ga-adị ka ihe ndị ọzọ ụfọdụ na-eru nso (eg, stratified ụfọdụ) na ndị ọzọ ukpụhọde eru nso (eg, post-stratification). Maka ozi on online ogwe,-ahụ Callegaro et al. (2014) .

Mgbe ụfọdụ, ndị nchọpụta achọpụtawo na ihe gbasara nke puru samples na-abụghị nke puru omume samples-ekwenyere kwuru nke yiri àgwà (Ansolabehere and Schaffner 2014) , ma ndị ọzọ na-atụnyere ndị achọpụtala na ndị na-abụghị nke puru omume samples, ime ihe ọjọọ (Malhotra and Krosnick 2007; Yeager et al. 2011) . One pụrụ iso mee ka ndịrịta iche ndị a bụ na ndị na-abụghị nke puru omume samples mma karịrị oge. N'ihi na a ọzọ pessimistic echiche nke na-abụghị nke puru omume ụfọdụ ụzọ hụ na AAPOR Task Force on Non-puru omume nlele (Baker et al. 2013) , na M nwere ike ikwu na-agụ nkọwa nke ga-esochi nchịkọta akụkọ a.

N'ihi na a meta-analysis na mmetụta nke weighting iji belata echiche ọjọọ na-abụghị nke puru omume samples, na-ahụ Isiokwu 2.4 na Tourangeau, Conrad, and Couper (2013) , nke na-eduga ndị dere na ya ikwubi "mgbanwe yiri ka ọ bara uru ma ikom na-ezughị degharịa. . . "

• Esi ajụ (Nkebi 3.5)

Conrad and Schober (2008) na-enye ihe dezie olu akpọ Envisioning na Survey Interview nke Future, ọ na-agwa ọtụtụ n'ime isiokwu na nkebi nke a. Couper (2011) na-agwa yiri gburugburu, na Schober et al. (2015) awade a mara mma ihe atụ nke otú data collection ụzọ na-ahaziri iji ntọala ọhụrụ pụrụ ịkpata elu mma data.

N'ihi ọzọ na-akpali ihe atụ nke na-eji Facebook ngwa ọdịnala na-elekọta mmadụ na sayensị nnyocha ndị e mere, lee Bail (2015) .

Maka ozi ndụmọdụ na-eme nnyocha ndị e mere na-atọ ụtọ na ihe ndị bara uru maka sonyere, ịhụ ọrụ na ahaziri Design Method (Dillman, Smyth, and Christian 2014) .

Stone et al. (2007) awade a akwụkwọ ogologo ọgwụgwọ nke ebe obibi nwa oge ntule na metụtara ụzọ.

• Nnyocha ndị e mere jikọrọ ọzọ data (Nkebi 3.6)

Judson (2007) kwuru na usoro nke na ijikọta nnyocha ndị e mere na nhazi data dị ka "ozi mwekota," eneme ụfọdụ uru nke a, na awade ihe atụ ụfọdụ.

Ụzọ ọzọ na-eme nnyocha nwere ike iji dijitalụ metụtara na nhazi data bụ ụfọdụ etiti maka ndị na kpọmkwem e ji mara. Otú ọ dị, nweta ndekọ ahụ na-eji ụfọdụ etiti nwekwara ike ike ajụjụ ndị metụtara nzuzo (Beskow, Sandler, and Weinberger 2006) .

Banyere adịkwu ajụ, ime nke a ọ bụghị dị ka ọhụrụ dị ka ọ pụrụ iyi si otú m na-akọwara ya. Nke a na obibia nke ukwuu njikọ atọ nnukwu ebe ke ọnụ ọgụgụ-nlereanya dabeere na post-stratification (Little 1993) , imputation (Rubin 2004) , na obere ebe ọnu (Rao and Molina 2015) . Ọ na-metụtara na ojiji nke surrogate variables na nchọpụta ọgwụ na (Pepe 1992) .

Na mgbakwunye na usoro ziri ezi ihe iseokwu banyere ịnweta digital Chọpụta data, adịkwu ajụ nwekwara ike-eji na-infer mwute àgwà ndị mmadụ wee ghara ahọrọ na-ekpughe na a nnyocha e mere (Kosinski, Stillwell, and Graepel 2013) .

Ndị na-eri na oge atụmatụ na Blumenstock, Cadamuro, and On (2015) na-ezo ihe na-agbanwe na-eri-eri nke onye ọzọ nnyocha e mere-na anaghị agụnye ofu-akwụ ụgwọ dị ka ndị na-eri ọcha na hazie oku data. Ke ofụri ofụri, adịkwu ajụ ga-enwe nnukwu ofu-akwụ ụgwọ na ala variable akwụ ụgwọ yiri digital nwere (gụọ Isi nke 4). More nkọwa na data eji na Blumenstock, Cadamuro, and On (2015) akwụkwọ na- Blumenstock and Eagle (2010) na Blumenstock and Eagle (2012) . Na-eru Nso si multiple imputuation (Rubin 2004) nwere ike inyere kpọọ ejighị ihe n'aka na atụmatụ e mere si adịkwu ajụ. Ọ bụrụ na nnyocha ime adịkwu arịọ naanị na-eche banyere nchịkọta adabere, kama onye-larịị àgwà, mgbe ahụ na-eru nso na King and Lu (2008) na Hopkins and King (2010) nwere ike ịbụ bara uru. N'ihi na ihe banyere igwe mmụta na-eru nso na Blumenstock, Cadamuro, and On (2015) , na-ahụ James et al. (2013) (ihe mmeghe) ma ọ bụ Hastie, Tibshirani, and Friedman (2009) (elu ndị ọzọ). Ọzọ na-ewu ewu igwe mmụta akwụkwọ ọgụgụ bụ Murphy (2012) .

Banyere enriched ajụ, na ya pụta na Ansolabehere na Hersh (2012) mgbabere uzo on abụọ isi nzọụkwụ: 1) ikike nke Catalist ikpokọta ọtụtụ disparate data isi mmalite na-emepụta ezi-nwe-datafile na 2) ikike nke Catalist ejikọta ihe nnyocha e mere data na- nwe ya datafile. Ya mere, Ansolabehere na Hersh ịlele ọ bụla nke ndị a nke ọma.

Kee nwe-datafile, Catalist agwakọta na-ekwekọ ọmụma si dị iche iche na isi mmalite gụnyere: multiple ịtụ vootu ndia snapshots n'ebe onye ọ bụla ala, data si Post Office si National Change nke Address Registry, na data site na ndị ọzọ unspecified azụmahịa na enye. The Góry nkọwa banyere otú ihe a nile ihicha na merging na-eme ndị nọ n'ofe akporo nke akwụkwọ a, ma nke a usoro, n'agbanyeghị otú ịkpachara anya, ga-mgba na njehie na mbụ data isi mmalite na ga-ewebata njehie. Ọ bụ ezie na Catalist dị njikere iji tụlee ya data nhazi na-enye ụfọdụ n'ime ya ndu data, ọ bụ nanị agaghị ekwe omume n'ihi na-eme nnyocha iji nyochaa dum Catalist data pipeline. Kama nke ahụ, na-eme nnyocha nọ n'ọnọdụ ebe ihe Catalist data file nwere ụfọdụ na-amaghị ama, ma eleghị anya, ịmata amata, ego nke njehie. Nke a bụ a dị mkpa n'ihi na a critic nwere ike ịkọ nkọ na nnukwu ọdịiche dị n'etiti nnyocha e mere akụkọ na CCES na omume na Catalist nwe data file e mere site na njehie na-nwe data file, ọ bụghị site misreporting site zaghachirinụ.

Ansolabehere na Hersh were abụọ dị iche iche bịara ibi nwatakịrị agwa okwu bụ data àgwà nchegbu. Akpa, na mgbakwunye na-atụnyere onwe kọrọ ịtụ vootu na ịtụ vootu na Catalist nwe faịlụ, na-eme nnyocha na-tụnyere onwe kọrọ party, agbụrụ, Voter registration ọnọdụ (eg, aha ma ọ bụ adịghị aha) na ịtụ vootu usoro (eg, na onye, ​​gbahapụrụ vootu, wdg) ndị ụkpụrụ ndị dị na Catalist ọdụ data. N'ihi na anọ ndị a omume igwe mmadụ variables, ndị na-eme nnyocha na ole ọkwa dị elu nke nkwekọrịta n'etiti nnyocha e mere akụkọ na data na Catalist nwe-file karịa maka ịtụ vootu. N'ihi ya, Catalist nwe data file yiri ka elu àgwà ozi maka àgwà ndị ọzọ karịa ịtụ vootu,-atụ aro na ọ bụghị nke ogbenye n'ozuzu àgwà. Nke abụọ, na akụkụ site na iji data site Catalist, Ansolabehere na Hersh mepụtara atọ dị iche iche ihe nke àgwà nke Okeechobee ịtụ vootu ndia, ha chọpụtara na-eme atụmatụ ọnụego nke n'elu-akuko nke ịtụ vootu bụ nnoo nweghị mmekọ ọ bụla n'ime ndị a data àgwà jikoro, a Inweta na -atụ aro na elu ọnụego nke n'elu-akuko na-adịghị chụpụrụ site ógbè na unusually ala data mma.

Nyere ihe e kere eke nke a ọkà ịtụ vootu faịlụ, nke abụọ isi iyi nke nwere njehie na-ejikọ ndị nnyocha e mere na ndekọ na ya. Dị ka ihe atụ, ọ bụrụ na a linkage a na-eme ọhụma na ọ pụrụ iduga na-n'elu-atụmatụ nke dị iche n'etiti kọrọ na irè ịtụ vootu omume (Neter, Maynes, and Ramanathan 1965) . Ọ bụrụ na ọ bụla onye na nwere a ufọk ufene, ihe nchọpụta pụrụ iche nke di na abụọ data isi mmalite, mgbe ahụ, linkage ga-adịchaghị mkpa. Dị na US na ọtụtụ mba ndị ọzọ, Otú ọ dị, ọ dịghị eluigwe na ala nchọpụta. Ọzọkwa, ọ bụrụgodị na e nwere ndị dị otú ahụ nchọpụta ndị nwerela ike esiri nye ya ka ọ na-elegharị na-eme nnyocha! N'ihi ya, Catalist nwere ime linkage iji na-ezughị okè nchọpụta, na nke a anọ iberibe ọmụma banyere onye ọ bụla respondent: aha, okike, nwa afọ, na adreesị ụlọ. Dị ka ihe atụ, Catalist nwere na-ekpebi ma ọ bụrụ na Homie J simpson na CCES ka bụ otu onye dị ka Homer Jay simpson na nna ha ukwu data faịlụ. Na omume, kenha bụ a siri ike ma na-eru unyi usoro, na, na-eme ka ihe ka ndị na-eme nnyocha, Catalist atụle ya kenha Usoro na-proprietary.

Iji emere ebere ka kenha algọridim, ha dabeere n'ebe nsogbu abụọ. Akpa, Catalist abuana ke a kenha mpi na-agba ọsọ site otu nọọrọ onwe ha,-atọ ndị ọzọ: na MITRE Corporation. MITRE nyere ndị niile sonyere abụọ ụzụ data faịlụ-adịkwa, na dị iche iche na ìgwè mpi iji laghachi MITRE kasị mma kenha. N'ihi na MITRE onwe ya maara ihe ziri ezi kenha ha na-enwe ike Akara na ìgwè. Nke 40 na ụlọ ọrụ ndị na mpi, Catalist nọ n'ọnọdụ nke abụọ ebe. Nke a na ụdị onwe ha,-atọ ndị ọzọ nwale nke proprietary technology bụ nnọọ obere na-incredibly bara uru; ọ ga-enye anyị obi ike na Catalist si kenha usoro bukwa nnoo na ala-nke na-art. Ma bụ ala-nke na-art mma? Tụkwasị na nke a kenha mpi, Ansolabehere na Hersh kere ha kenha esiri Catalist. Site na mbụ oru ngo, Ansolabehere na Hersh nwetara Voter ndia si Florida. Ha nyere ụfọdụ n'ime ndị a ndia na ụfọdụ n'ime ubi ha redacted ka Catalist wee tụnyere Catalist si akụkọ banyere ndị a n'ubi iji ha hà n'ezie ụkpụrụ. Ọ dabara nke ọma, Catalist si akụkọ ndị fọrọ obere ka e jichie ụkpụrụ, na-egosi na Catalist nke pụrụ ịdị ele mmadụ anya n'ihu Voter ndia jidesie nna ha ukwu data faịlụ. Ndị a nsogbu abụọ, otu a-atọ ndị ọzọ na otu site Ansolabehere na Hersh, na-enye anyị ihe obi ike na Catalist kenha algọridim, ọ bụ ezie na anyị enweghị ike inyocha ha kpọmkwem, mmejuputa iwu onwe anyị.

E nwere ọtụtụ Ngbali iji emere ebere ịtụ vootu. N'ihi na ihe nnyocha nke na akwụkwọ, na-ahụ Belli et al. (1999) , Berent, Krosnick, and Lupia (2011) , Ansolabehere and Hersh (2012) , na Hanmer, Banks, and White (2014) .

Ọ dị mkpa iburu n'obi na ọ bụ ezie na nke a na-eme nnyocha agbamume bụ àgwà nke data site Catalist, ndị ọzọ nwete nke azụmahịa mgbere ndidi na-erughị ịnụ ọkụ n'obi. -Eme nnyocha achọpụtala ogbenye mma mgbe data site na a nnyocha e mere ka a n'ji-faịlụ site Marketing Systems Group (nke onwe ya mechakwara gbakwụnyeghachi akwụkwọ ụfọdụ ọnụ data site na atọ na enye: Acxiom, Experian, na InfoUSA) (Pasek et al. 2014) . Ya bụ, data file ekwekọghị na nnyocha e mere na-azaghachi na-eme nnyocha atụ anya na-ezi, na datafile ama efu data maka a ukwuu nke ajụjụ, na-efu data ụkpụrụ e mekọrịtara ka kọrọ nnyocha e mere uru (ndị ọzọ okwu efu data bu usoro , ọ bụghị random).

Maka ozi on ndekọ linkage n'etiti nnyocha ndị e mere na nhazi data, ịhụ Sakshaug and Kreuter (2012) na Schnell (2013) . Maka ozi on ndekọ linkage n'ozuzu,-ahụ Dunn (1946) na Fellegi and Sunter (1969) (akụkọ ihe mere eme) na Larsen and Winkler (2014) (oge a). Yiri na-eru nso nakwa na e mepụtara na kọmputa sayensị n'okpuru aha dị ka data deduplication, atụ njirimara, aha kenha, oyiri nchọpụta, na oyiri ndekọ nchọpụta (Elmagarmid, Ipeirotis, and Verykios 2007) . E nwekwara nzuzo echebekwa-eru nso ka ịdekọ linkage nke-anaghị achọ nnyefe nke onwe-akọwapụta ọmụma (Schnell 2013) . -Eme nchọpụta na Facebook mepụtara a usoro na-probabilisticsly ejikọta ha na ndekọ na-ịtụ vootu omume (Jones et al. 2013) ; a linkage ka e mere iji inwale nnwale na m agwa gị banyere n'Isi nke 4 (Bond et al. 2012) .

Ihe atụ ọzọ nke na-ejikọ a nnukwu-ọnụ ọgụgụ na-elekọta mmadụ nnyocha e mere na ọchịchị administrative ndia abịa site Health na Retirement Survey na Social Security Administration. Maka ozi on na-amụ, gụnyere ozi banyere nkwenye usoro, ịhụ Olson (1996) na Olson (1999) .

The usoro nke na ijikọta ọtụtụ na isi mmalite nke administrative ndia n'ime a-nwe-datafile-usoro na Catalist ọrụ-na-ahukari n'ime mgbakọ na mwepụ ụlọ ọrụ ụfọdụ mba ọchịchị. Ndị nnyocha abụọ si Statistics Sweden dere a zuru ezu akwụkwọ n'isiokwu (Wallgren and Wallgren 2007) . N'ihi na ihe atụ nke a obibia na otu asị na United States (Olmstead County, Minnesota; n'ụlọ nke Mayo Clinic),-ahụ Sauver et al. (2011) . Maka ozi on njehie nke nwere ike ịpụta na administrative ndekọ, ịhụ Groen (2012) .