Imibuzo malunga nocalulo kwiphando loluntu luhlala luyinkimbinkimbi kwaye luyinkimbinkimbi. Ukufumana indlela yokusekela ngokususela kwiigrafu ze-causal, jonga i- Pearl (2009) , kunye nendlela yokwenza isiseko esekelwe kwiziphumo ezinokwenzeka, bona Imbens and Rubin (2015) . Ukuthelekisa phakathi kwezi ndlela zombini, bona Morgan and Winship (2014) . VanderWeele and Shpitser (2013) , jonga VanderWeele and Shpitser (2013) .
Kule sahluko, ndidale into ebonakalayo njengomgca oqaqambileyo phakathi kwamandla ethu okwenza uqikelelo lwama-causal ukusuka kwimizamo yokulinga nokungahlolisanga. Nangona kunjalo, ndicinga ukuba, ngokwenene, ukuhlukana kuphazamiseka. Umzekelo, wonke umntu uyamkela ukuba ukutshaya kubangela umdlavuza, nangona akukho vavanyo olulawulwa ngokungapheliyo olubangela ukuba abantu bashiye umsi. Ukufumana unyango Shadish, Cook, and Campbell (2001) kwi-data engeyiyo yokuhlola ubone Rosenbaum (2002) , ( ??? ) , Shadish, Cook, and Campbell (2001) kunye no- Dunning (2012) .
Izahluko 1 no-2 ze- Freedman, Pisani, and Purves (2007) zinikeza isingeniso esicacileyo kwimibono phakathi kwezilingo, ukuhlolwa okulawulwayo kunye nokuhlolwa okungalawulwa ngandlela-thile.
Manzi (2012) unika isingeniso Manzi (2012) zefilosofi kunye neenkalo zemizamo yokulawulwa ngokungahleliwe. Ikwabonelela ngemimiselo yehlabathi ngokwenene yamandla okuzama ukushishina. Issenberg (2012) unikeza isingeniso esithakazelisayo ekusebenziseni uvavanyo kumaphulo ezopolitiko.
Box, Hunter, and Hunter (2005) , @ casella_statistical_2008, kunye no- Athey and Imbens (2016b) banikezela izethulo ezilungileyo kwimilinganiselo yezinto zokubala kunye nokuhlalutya. Ukongezelela, kukho iindlela ezininzi zokongela iimvavanyo kwiindawo ezininzi ezahlukeneyo: i-economics (Bardsley et al. 2009) , i-sociology (Willer and Walker 2007; Jackson and Cox 2013) , ingqondo (Aronson et al. 1989) , isayensi yezopolitiko (Morton and Williams 2010) , kunye nomgaqo-nkqubo wezeNtlalo (Glennerster and Takavarasha 2013) .
Ukubaluleka kwabathathi-nxaxheba (umz., Isampula) kudlalwa phantsi kophando lovavanyo. Nangona kunjalo, ukuba impembelelo yonyango ihambelana noluntu, isampuli ibaluleke kakhulu. Longford (1999) yenza le ngongoma ngokucacileyo xa ekhuthaza abaphengululi bacinga iimvavanyo njengolu vavanyo lwentlalo kunye nesampula.
Ndiye ndacetyiswa ukuba kukho ukuqhubeka phakathi kweemvavanyo zelabhu kunye nenzululwazi, kwaye abanye abaphandi bacebise iinkcukacha ezininzi, ngokukhethekileyo ezahlula iintlobo ezahlukeneyo zokuhlola kwimihlaba (Harrison and List 2004; Charness, Gneezy, and Kuhn 2013) .
Inani lamaphepha alinganisa iil lab kunye nenzame zenzalo kwi-abstract (Falk and Heckman 2009; Cialdini 2009) kwaye ngokwemiqathango yeziphumo ezithile zenzululwazi yezopolitiko (Coppock and Green 2015) , ezoqoqosho (Levitt and List 2007a, 2007b; Camerer 2011; Al-Ubaydli and List 2013) , kunye neengqondo (Mitchell 2012) . Jerit, Barabas, and Clifford (2013) banikezela uphando Jerit, Barabas, and Clifford (2013) . Parigi, Santana, and Cook (2017) ichaza indlela ukuhlolwa kwimihlaba ye-intanethi kungadibanisa ngayo ezinye iimpawu zobungqina bebhan ne-field.
Ixhala malunga nabafundi abatshintsha indlela abaziphatha ngayo kuba bayazi ukuba bajongwa ngokugqithiseleyo ngamanye amaxesha kuthiwa yimpembelelo yemfuno , kwaye baye bafundiswa kwingqondo (Orne 1962) kunye nezoqoqosho (Zizzo 2010) . Nangona ininzi ihambelana nokuhlolwa kwebhu, le miba efanayo ingabangela iingxaki zemizamo yesimo. Enyanisweni, iimpembelelo zemfuno zibizwa ngezinye ii- Hawthorne , iziphumo ezifumana izilingo ezidumile zokukhanyisa ezaqala ngo-1924 kwi-Hawthorne Works ye-Western Electric Company (Adair 1984; Levitt and List 2011) . Zomibini iziphumo zemfuno kunye neempembelelo ze- Hawthorne zihlobene kakhulu nombono wokulinganiswa okucwangcisiweyo okuthethwa ngazo kwisahluko 2 (bona kwakhona i- Webb et al. (1966) ).
Uvavanyo (Shadish 2002) omude kwizoqoqosho (Levitt and List 2009) , isayensi yezopolitiko (Green and Gerber 2003; Druckman et al. 2006; Druckman and Lupia 2012) , i-Psychology (Shadish 2002) , kunye nomgaqo-nkqubo (Shadish and Cook 2009) . Enye indawo yenzululwazi yentlalo apho uphando olwenziwe ngokukhawuleza lwaba luphawu oluphuhliso lwamazwe ngamazwe. Ukuhlaziywa okulungileyo kwaloo msebenzi ngaphakathi kwezoqoqosho, khangela Banerjee and Duflo (2009) , kunye novavanyo olubalulekileyo jonga Deaton (2010) . Ukuphononongwa kwalo msebenzi kwizenzululwazi zezopolitiko ubone Humphreys and Weinstein (2009) . Ekugqibeleni, imingeni yokuziphatha eyenziwa kwimizamo yenkalo iye yahlolwa kwimeko yesayensi yezopolitiko (Humphreys 2015; Desposato 2016b) kunye noqoqosho lwezoqoqosho (Baele 2013) .
Kule candelo, ndacetyiswa ukuba ulwazi lwengonyango lungasetyenziselwa ukuphucula ukuchaneka kweziphumo zonyango, kodwa kukho ingxoxo malunga nale ndlela; ubona u- Freedman (2008) , W. Lin (2013) , Berk et al. (2013) , kunye ne- Bloniarz et al. (2016) ngolwazi olungakumbi.
Ekugqibeleni, kukho ezinye iindidi zemizamo eyenziwa yenzululwazi zentlalo engahambelani kakuhle kwi-lab-field dimension: iimvavanyo zophando kunye nokuhlolwa kweentlalo. Uvavanyo lokuphonononga luzama ukusebenzisa izibonelelo zophando olukhoyo kwaye uqhathanise iimpendulo kwezinye iinguqulelo zemibuzo efanayo (uvavanyo oluthile lwenziwa kwiSahluko 3); ukufumana okungaphezulu kwiimvavanyo zophando zibona Mutz (2011) . Uvavanyo lwezentlalo luyilingo apho unyango lolunye umgaqo-nkqubo wezenhlalakahle onokusetyenziswa kuphela nguRhulumente. Iimvavanyo zentlalo zihlobene ngokuvisisana novavanyo lwenkqubo. Ngolunye ulwazi malunga nokuhlolwa kwepolisi, bona Heckman and Smith (1995) , Orr (1998) , kunye ne-glennerster_running_2013.
Ndikhethile ukugxila kwiingcamango ezintathu: ukuqinisekiswa, ukuchithwa kwamathambo kunye nezixhobo. Ezi ngcamango zinamagama ahlukeneyo kwimimandla eyahlukeneyo. Ngokomzekelo, oogqirha beengqondo bavame ukudlulela ngaphaya kwezilingo ezilula ngokugxininisa kubalamli nabaodareyitha (Baron and Kenny 1986) . Iingcamango zabalamli zifunyenwe yizinto endichithayo, kwaye iingcamango zeemodareyitha zifakwe yinto endiyibiza ngokuba yinyaniso yangaphandle (umzekelo, ngaba iziphumo zovavanyo zizahluka uma ziqhutywa kwiimeko ezahlukeneyo) kunye neempembelelo zonyango ( umzekelo, iziphumo ezinkulu kwabanye abantu kunabanye).
Uvavanyo Schultz et al. (2007) ibonisa indlela iingcamango zentlalo ezisetyenziselwa ngayo ukucwangcisa ukungenelela ngempumelelo. Ngengxabano evamile malunga nendima yombono ekuqulunqweni kwamanyathelo angenelelo, bona Walton (2014) .
Iingcamango zangaphakathi kunye nangaphandle ziqaliswe Campbell (1957) . Jonga Shadish, Cook, and Campbell (2001) ukungqinelana kwangaphakathi, ukwakha ukuqinisekiswa, kunye nokusebenza kwangaphandle.
Ukujonga ngokubanzi imicimbi ehambelana nokugqitywa kwezibalo eziqinisekileyo kwiimvavanyo zibone i- Gerber and Green (2012) (ukusuka kwindlela yezesayensi yentlalo) kunye ne- Imbens and Rubin (2015) (ukusuka kumbono wenani). Eminye imiba yesigqibo esiphezulu esichazwe ngokukodwa kwiimvavanyo zentsimi ye-intanethi ziquka imiba efana neendlela ezifanelekileyo zokubamba ukuzithemba kunye neenkcukacha (Bakshy and Eckles 2013) .
Ukusebenza kwangaphakathi kunokuba nzima ukuqinisekisa kwiimvavanyo ezinzima zentsimi. Uyabona, umzekelo, Gerber and Green (2000) , Imai (2005) , kunye Gerber and Green (2005) ngenjongo yokuxubusha malunga nokuphunyezwa kwinkalo eyinkimbinkimbi yenzalo malunga nokuvota. Kohavi et al. (2012) kunye no Kohavi et al. (2013) inikezela isingeniso kwimingeni yokusebenza kwexesha lokuvavanya kwintsimi ye-intanethi.
Esinye isongelo esisisiseko sokusebenza kwangaphakathi kukuba kungenzeka ukuhluleka ukulandelelana. Enye indlela ekhoyo yokufumana iingxaki ngokulandelelanisa kukuqhathanisa unyango kunye namaqela okulawula kwiimpawu ezibonakalayo. Olu hlobo lokuthelekisa lubizwa ngokuba ngumgca wokujonga . Jonga Hansen and Bowers (2008) ngenkqubo yokulinganisa ukulinganisa i-check and Mutz and Pemantle (2015) malunga neengxaki malunga nokuhlola i-balance. Umzekelo, usebenzisa i-check balance, u- Allcott (2011) ufumene ubungqina bokuthi ukungazange kwenziwe ngokuchanekileyo kungakhange kwenziwe ngokufanelekileyo kwiimvavanyo ezintathu zokuSebenza (bona itheyibhile yesi-2; ii-sites 2, 6, no-8). Ngezinye iindlela, funda isahluko 21 se- Imbens and Rubin (2015) .
Ezinye iinkxalabo eziphambili ezinxulumene nokusebenza kwangaphakathi zilandelayo: (1) ukungahambisani nomgangatho omnye, apho kungekhona wonke umntu eklasini yonyango efumanekileyo unyango, (2) ukungahambisani nokubambisana, apho kungenjalo wonke umntu eklasini yonyango ufumana unyango kunye nabanye abantu iqela lokulawula lifumana unyango, (3) ummiselo, apho iziphumo ezingenakulinganiswa kwabanye abathathi-nxaxheba, kunye (4) nokuphazamiseka, apho unyango luchithwa kubantu abahlala kwimeko yokunyanga kubantu abakwiimeko zokulawula. Jonga izahluko 5, 6, 7, kunye ne-8 Gerber and Green (2012) ngezinye zazo kule micimbi.
Ukufumana okungakumbi ukwakhiwa okusemthethweni, khangela Westen and Rosenthal (2003) , kunye nokunye okukwakha ekuqinisekiseni imithombo yemithombo emikhulu, Lazer (2015) kunye nesahluko 2 sale ncwadi.
Enye into yokusebenza kwangaphandle yindlela apho kungenelelwa khona ukungenelela. Allcott (2015) unikezela Allcott (2015) kwendawo yokukhetha indawo. Lo mbandela uphinde Deaton (2010) . Enye into yokusebenza kwangaphandle kukuba ingaba ukusetyenziswa okuthe ngenye indlela kungenelelo elifanayo. Kule meko, umzekelo phakathi Schultz et al. (2007) kunye no- Allcott (2011) ubonisa ukuba iimvavanyo zokuSebenza ziba nefuthe elincinciweyo elingaphantsi kwezonyango zangaphambili zakwaSchultz kunye noogxa (1.7% ngokumalunga ne-5%). Allcott (2011) wacacise ukuba ukulandelwa kokulandelelana kwakunomphumo omncinci ngenxa yeendlela iindlela ezahlukeneyo zonyango ezihluke ngayo: i-emoticon ebhaliweyo ngesandla njengenxalenye yesifundo esixhaswe yiyunivesiti, xa kuthelekiswa ne-emoticon eprintiweyo njengenxalenye yesistim ingxelo evela kwinkampani yamandla.
Ukuze uphononongo oluhle kakhulu lwe-heterogeneity yeempembelelo zonyango kwiimvavanyo zentsimi, funda isahluko 12 Gerber and Green (2012) . Kravitz, Duan, and Braslow (2004) kweempembelelo zonyango kwizilingo zonyango, bona Kent and Hayward (2007) , i- Longford (1999) , kunye Kravitz, Duan, and Braslow (2004) . Ukuqwalaselwa ngokuchaneka kweempembelelo zonyango ngokubanzi kugxininisa kwiimeko ezahlukileyo ngokubhekiselele kwimpawu zonyango. Ukuba unomdla kwi-heterogeneity esekelwe kwiziphumo zonyango emva koko, kukho iindlela eziyinkimbinkimbi ezifunekayo, njenge-stratification (Frangakis and Rubin 2002) ; Bona i- Page et al. (2015) ukuhlaziywa.
Abaphengululi abaninzi bacinga ukuba i-heterogeneity effect effect effects using regression, kodwa iindlela ezintsha zithembela ekufundeni komatshini; ubone, umzekelo, Green and Kern (2012) , Imai and Ratkovic (2013) , Taddy et al. (2016) , kunye no- Athey and Imbens (2016a) .
Kukho ukungazithembi malunga nokufunyaniswa kweengxaki ze-heterogeneity ngenxa yeengxaki zokuqhathanisa ezininzi kunye "nokuloba." Kukho iindlela ezahlukeneyo ezinokubangela ukujongana neengxaki malunga nokuqhathaniswa okubanzi (Fink, McConnell, and Vollmer 2014; List, Shaikh, and Xu 2016) . Enye indlela yokuxhalabisa ngokuphathelele "ukuloba" kubhaliso lwangaphambi kokubhalisa, oluye lwaba luxhaphake kakhulu kwizengqondo (Nosek and Lakens 2014) , isayensi yezopolitiko (Humphreys, Sierra, and Windt 2013; Monogan 2013; Anderson 2013; Gelman 2013; Laitin 2013) , kunye noqoqosho (Olken 2015) .
Kuhlolisiso Costa and Kahn (2013) kuphela malunga nesiqingatha samakhaya ekuhlolweni kunokudibaniswa nolwazi lwabantu. Abafundi abanomdla kule nkcukacha kufuneka babhekise kwiphepha lokuqala.
Iinkqubo zibaluleke kakhulu, kodwa ziya kuba nzima kakhulu ukufunda. Uphando malunga neendlela zihambelana VanderWeele (2009) beengqondo (kodwa jonga kwakhona VanderWeele (2009) ngokuthelekiswa okucacileyo phakathi kweembono ezimbini). Izindlela zokwenza isistim zokufumana iinkqubo, ezifana nendlela eya Baron and Kenny (1986) , ziqhelekile. Ngelishwa, kuvela ukuba le nkqubo ixhomekeka kwiingcamango ezinzulu (Bullock, Green, and Ha 2010) kwaye zihlupheke xa kukho iindlela ezininzi, njengoko umntu angalindela kwiimeko ezininzi (Imai and Yamamoto 2013; VanderWeele and Vansteelandt 2014) . Imai et al. (2011) kunye no- Imai and Yamamoto (2013) banikezela iindlela zokuphucula izibalo. Ngokuqhubekayo, VanderWeele (2015) inikeza unyango VanderWeele (2015) ngemiphumo ebalulekileyo, kubandakanya indlela epheleleyo yokuhlalutya ukuqonda.
Indlela eyahlukileyo ijolise kwiimvavanyo ezama ukusetyenziswa ngendlela echanekileyo (umzekelo, ukunika abahamba ngee-vitamin C). Ngelishwa, kwiimeko ezininzi zesayensi zentlalo, kukho iindlela ezininzi kwaye kunzima ukuyila unyango olutshintsha ngaphandle kokuguqula abanye. Ezinye iindlela zokwenza iindlela zokutshintsha ngokuchanekileyo zichazwa ngu- Imai, Tingley, and Yamamoto (2013) , Ludwig, Kling, and Mullainathan (2011) , kunye no- Pirlott and MacKinnon (2016) .
Abaphandi abaqhuba iimvavanyo ezenzelwe ngokupheleleyo baya kufuna ukukhathazeka malunga nokuhlolwa kweengcinga ezininzi; sibone Fink, McConnell, and Vollmer (2014) kunye List, Shaikh, and Xu (2016) ukuze uthole ulwazi olungakumbi.
Ekugqibeleni, iinkqubo zinomlando omdala kwifilosofi yesayensi njengoko kuchazwe Hedström and Ylikoski (2010) .
Ukufumana okungakumbi ukusetyenziswa kweengxelo kunye neengxelo Pager (2007) ubandlululo, khangela Pager (2007) .
Indlela eqhelekileyo yokubambisa abathathi-nxaxheba kwiimvavanyo ozakhayo yi-Amazon Mechanical Turk (MTurk). Ngenxa yokuba i-MTurk ixubusha imiba yolu vavanyo lwebhanki yendabuko-abantu abahlawulayo ukugqiba imisebenzi abangazange bayenze kubaphandi abaninzi abakhululekileyo sele beqalile ukusebenzisa i-Turkers (abasebenzi baseMTurk) njengabathathi-nxaxheba, okubangela ukuqokelela kwedatha okuncinci nangakumbi kunokungagqibekanga. kwi-laboratory ye-laboratory (Paolacci, Chandler, and Ipeirotis 2010; Horton, Rand, and Zeckhauser 2011; Mason and Suri 2012; Rand 2012; Berinsky, Huber, and Lenz 2012) .
Ngokuqhelekileyo, inzuzo enkulu ekusebenziseni abathathi-nxaxheba abaqashiweyo esuka kwi-MTurk banesigxina. Nangona uvavanyo lweebhabhi lunokuthatha iiveki ukuqhuba kunye nokuhlolwa kwimihlaba kungathatha inyanga ukusetha, ukuvavanywa kwabathathi-nxaxheba abaqeshwe kwi-MTurk banokuqhutywa ngeentsuku. Ngokomzekelo, Berinsky, Huber, and Lenz (2012) bakwazi ukufumana izifundo ezingama-400 ngosuku olulodwa ukuba bathathe inxaxheba kwimvavanyo engama-8. Ukuqhubela phambili, abathathi-nxaxheba bangabhalwa malunga naluphi na injongo (kubandakanywa uphando kunye nentsebenziswano eninzi, njengoko kuthethwe kwizahluko 3 no-5). Olu lula lokuqashwa lithetha ukuba abaphandi banokuhamba ngokulandelelana kwezilingo ezihambelanayo ngokulandelelana ngokukhawuleza.
Ngaphambi kokuqesha abathathi-nxaxheba abavela kwi-MTurk kwiimvavanyo zakho, kukho izinto ezine ezibalulekileyo ofuna ukuzazi. Okokuqala, abaninzi abaphandi banokungaboni ngokucacileyo ukuvavanya kweemvavanyo ezibandakanya iTurkers. Ngenxa yokuba le nkcazo ayikho into ecacileyo, kunzima ukuphikisa ubungqina. Nangona kunjalo, emva kweminyaka emininzi yophando usebenzisa i-Turkers, ngoku sinokugqiba ukuba le ngxaki ayifanelekanga. Kukho izifundo ezininzi ezithelekisa iinkcukacha zabantu baseTurkers kunye nabanye abantu kunye nezifundo ezininzi ezithelekisa iziphumo zovavanyo kunye noTurkers kubangelwa ngabanye abantu. Ukunikezelwa kwalo msebenzi wonke, ndicinga ukuba indlela engcono kakhulu yokuba ucinge ngayo kukuba iTurkers iyisampula esilungeleyo, njengabafundi kodwa iindawo ezahlukeneyo (Berinsky, Huber, and Lenz 2012) . Ngaloo ndlela, njengokuba abafundi banabantu abathile, kodwa akusiyo yonke into, uphando, i-Turkers yindawo enengqiqo kwabanye, kodwa akuyiyo yonke, uphando. Ukuba uya kusebenza kunye neTurkers, kuyacaca ukuba ufunde ezininzi zezifundo ezithelekisayo kunye nokuqonda imiba yabo.
Okwesibini, abaphandi baye baqulunqa iindlela ezifanelekileyo zokunyusa ukuqinisekiswa kwangaphakathi kweemvavanyo ze-MTurk, kwaye kufuneka ufunde ngokulandelelanisa le ndlela (Horton, Rand, and Zeckhauser 2011; Mason and Suri 2012) . Ngokomzekelo, abaphandi abasebenzisa iTurkers bakhuthazwa ukuba basebenzise iifowuni ukususa abachaphazelekayo abathathi-nxaxheba (Berinsky, Margolis, and Sances 2014, 2016) (kodwa bonani no- DJ Hauser and Schwarz (2015b) kunye no- DJ Hauser and Schwarz (2015a) ). Ukuba awususeli abathathi-nxaxheba abangenamdla, ngoko nayiphi na impembelelo yonyango inokuhlanjululwa ngxolo abayifakayo, kwaye ngokwenza inxaxheba inani labangenayo inxaxheba linokuba lukhulu. Kuvavanyo lukaHuber kunye noogxa (2012) , malunga ne-30% yabathathi-nxaxheba abahluleki ngqalelo kwiinkcazo zesikhokelo. Ezinye iingxaki ezivame ukuvela xa iTurkers zisetyenziselwa ukuba bathathi-nxaxheba (Chandler et al. 2015) kunye ne-attrition (Zhou and Fishbach 2016) .
Okwesithathu, ngokumalunga nezinye iindidi zophando zedijithali, iimvavanyo ze-MTurk azikwazi ukukhula; Stewart et al. (2015) liqikelele ukuba nangaliphi na ixesha elithile kukho abantu abangama-7,000 kuphela kwi-MTurk.
Ekugqibeleni, kufuneka ukwazi ukuba uMaturk uluntu kunye nemithetho yakhe kunye nemigangatho (Mason and Suri 2012) . Ngendlela efanayo ukuba uzama ukufumana malunga nenkcubeko yelizwe apho uya kuqhuba khona iimvavanyo zakho, kufuneka uzame ukufumana okungakumbi malunga nenkcubeko kunye nemigangatho yeTurkers (Salehi et al. 2015) . Kwaye kufuneka ukwazi ukuba abaTurkers baya kuthetha ngokuzama kwakho ukuba wenza into engafanelekanga okanye engekho (Gray et al. 2016) .
I-MTurk yindlela elula kakhulu yokubamba iqhaza kwiimvavanyo zakho, ingaba zifana neebra, ezifana Huber, Hill, and Lenz (2012) , okanye ezinye izinto ezifana Mason and Watts (2009) , Goldstein, McAfee, and Suri (2013) , Goldstein et al. (2014) , Horton and Zeckhauser (2016) , kunye Mao et al. (2016) .
Ukuba ucinga ukuzama ukwenza umkhiqizo wakho, ndincoma ukuba ufunde isiluleko esinikezwa iqela le-MovieLens Harper and Konstan (2015) . Ingqiqo ebalulekileyo evela kumava abo kukuba kwiprojekthi nganye ephumeleleyo kukho ezininzi, ukuhluleka kwamaninzi. Ngokomzekelo, iqela le-MovieLens liqalise ezinye iimveliso, ezifana ne-GopherAnswers, ezazingaphumeleli ngokupheleleyo (Harper and Konstan 2015) . Omnye umzekelo womphandi ohlulekayo xa ezama ukwenza umveliso ngu-Edward Castronova umzamo wokwakha umdlalo we-intanethi obizwa ngeArden. Ngaphandle kwe-$ 250,000 ngenkxaso-mali, le projekthi yayiyi-flop (Baker 2008) . Iiprojekthi ezifana neGopherAnswers kunye neArden ngelishwa kuninzi kakhulu kuneeprojekthi ezifana ne-MovieLens.
Ndive ingcamango yePetteur's Quadrant exubusha rhoqo kwiinkampani zobuchwepheshe, kwaye inceda ukuququzelela imizamo yophando kwiGoogle (Spector, Norvig, and Petrov 2012) .
I-Bond kunye noogxa bafunda nabo (2012) bazama ukufumanisa impembelelo yalezi zonyango kubahlobo balabo bawamkeleyo. Ngenxa yoyilo lovavanyo, ezi zinto zilukhuni ukubona ukucoceka; Abafundi abanomdla kufuneka babone Bond et al. (2012) kwingxoxo epheleleyo. UJohn kunye nabo basebenzisana naye (2017) nabo baqhuba uvavanyo olufanayo ngexesha lokhetho luka-2012. Ezi zilingo ziyinxalenye yenkcubeko ende yezovavanyo kwisayensi yezopolitiko kwimigudu yokukhuthaza ukuvota (Green and Gerber 2015) . Ezi ziphumo zokuvavanya zivakala, ziyinxalenye kuba zikhona kwi-Quadrant yePasteur. Okokuthi, baninzi abantu abakhuthazwayo ukwandisa ukuvota nokuvota kungenza ukuziphatha okuthakazelisayo ukuvavanya iingcamango eziqhelekileyo malunga nokuguquka kokuziphatha kunye nempembelelo yentlalo.
Ukuze ufumane iingcebiso malunga nokuhlolwa kwimihlaba kunye nemibutho yabalingani, njengamaqela ezopolitiko, ii-NGOs kunye namashishini, bona Loewen, Rubenson, and Wantchekon (2010) , JA List (2011) , no- Gueron (2002) . Ukucinga malunga nendlela intsebenziswano kunye nemibutho inokuchaphazela ngayo iiplani zophando, bona King et al. (2007) kunye Green, Calfano, and Aronow (2014) . Intsebenziswano inokukhokelela kwimibandela yokuziphatha, njengoko kuthethwa yi- Humphreys (2015) kunye no- Nickerson and Hyde (2016) .
Ukuba uya kudala isicwangciso sokuhlalutya ngaphambi kokuba usebenzise ukuhlolwa kwakho, ndincoma ukuba uqale ngokufunda izikhokelo zokunika ingxelo. I-CONSORT (I-Consolidated Standard Reporting of Trials) izikhokelo zenziwe ngamayeza (Schulz et al. 2010) kwaye zatshintshelwe uphando loluntu (Mayo-Wilson et al. 2013) . Isiqulatho esihambelana nesiqulunqo senziwe ngabahleli be- Journal of Scientific Experimental Science (Gerber et al. 2014) (bona Mutz and Pemantle (2015) kunye Gerber et al. (2015) ). Ekugqibeleni, izikhokelo zengxelo ziye zaphuhliswa kwingqondo (APA Working Group 2008) , kwaye ubone Simmons, Nelson, and Simonsohn (2011) .
Ukuba udala isicwangciso sokuhlalutya, kufuneka uqikelele ukubhalisa kwangaphambi kokuba ubhaliso lwangaphambili luya kwandisa ithemba lokuba abanye baneziphumo zakho. Ukongeza, ukuba usebenza kunye neqabane, kuya kunciphisa ikhono lomlingani wakho wokutshintsha uhlalutyo emva kokubona iziphumo. Ukubhalisa kwangaphambili kubonakala ngokuqhelekileyo kwingqondo (Nosek and Lakens 2014) , isayensi yezopolitiko (Humphreys, Sierra, and Windt 2013; Monogan 2013; Anderson 2013; Gelman 2013; Laitin 2013) , kunye nezoqoqosho (Olken 2015) .
Ukucebisa iingcebiso ngokukhethekileyo kwimizamo ye-intanethi ye-intanethi iphinda ihanjiswe kwi- Konstan and Chen (2007) no- Chen and Konstan (2015) .
Into endiyibizile isicwangciso se-armada ngamanye amaxesha sibizwa ngokuba nguphando lwenkqubo ; ubona Wilson, Aronson, and Carlsmith (2010) .
Ngolunye ulwazi kwiimvavanyo zeMusicLab, jonga i- Salganik, Dodds, and Watts (2006) , i- Salganik and Watts (2008) , i- Salganik and Watts (2009b) , i- Salganik and Watts (2009a) kunye ne- Salganik (2007) . Ngolunye ulwazi kwiimarike ezithatha inqununu, bona Frank and Cook (1996) . Ukufumana okungakumbi ukukhupha inhlanhla kunye nobuchule ngokubanzi, yibona Mauboussin (2012) , Watts (2012) , Frank (2016) .
Kukho enye indlela yokuphelisa iintlawulo ezithatha inxaxheba apho abaphandi bafanele basebenzise ngokuqaphela: ukubhalisa. Kwiinkalo ezininzi ze-intanethi zenzelwa ukuba abathathi-nxaxheba baqulunqwe kwiimvavanyo kwaye abazange bahlawulwe. Imizekelo yale ndlela iquka i-Restivo kunye ne-van de Rijt (2012) ukuzama ukufumana imivuzo kwi-Wikipedia kunye neBond kunye ne-colleague (2012) ukuzama ukukhuthaza abantu ukuba bavote. Ezi amalinge musa ngokwenene zero variable cost-kunoko, baye zero iindleko eziguquguqukayo bophando. Kwizilingo ezinjalo, nangona iindleko kumntu ngamnye athatha incinci kakhulu, iindleko ezipheleleyo zinokuba zikhulu kakhulu. Abaphandi abaqhuba iimvavanyo ezinkulu kwi-intanethi bavame ukubonisa ukubaluleka kweempembelelo ezincinci zonyango ngokuthi le miphumo emincinci ingabaluleka xa isetyenziswa kubantu abaninzi. Ukucinga okufanayo kusebenza kwiindleko abaphandi abazenzayo kubathathi-nxaxheba. Ukuba ukuzama kwakho kubangela abantu abayizigidi ezigidi ukuba bachithe ngomzuzu omnye, ukuzama akuyona inobungozi kumntu othile, kodwa ngokubanzi kuye kwachitha phantse iminyaka emibini.
Enye indlela yokudala inkokhelo yentlawulo eyahlukeneyo kubathathi-nxaxheba kukusebenzisa i-lottery, indlela esetyenzisiweyo kuphando lophando (Halpern et al. 2011) . Ukufumana okungakumbi malunga nokuyila amava omsebenzisi Toomim et al. (2011) , bona Toomim et al. (2011) . Ukufumana okungakumbi malunga nokusebenzisa i-bots ukudala iimvavanyo zendleko eziguquguqukayo zibona ( ??? ) .
Ezi zintathu zikaR njengoko zacetywayo Russell and Burch (1959) zilandelayo:
"Ukutshintshwa ithetha endaweni izilwanyana abazi abahlala aphezulu eziphathekayo insentient. Ukunciphisa kuthetha ukuncipha kwamanani ezilwanyana ezisetyenziselwa ukufumana ingcaciso kwisixa elinikiweyo kwaye ngocwangco. Ukuphuculwa ithetha nayiphi ekuncipheni kwezenzo nobuzaza iinkqubo nabuntu isicelo kwabo izilwanyana nangoku ukuba kusetyenziswa. "
Izinto ezintathu ezi-R endizicebisayo azithethi ngaphezulu kwemigaqo yokuziphatha echazwe kwisahluko 6. Kunoko, iinguqu echazwe ngakumbi enye yale migaqo-inzuzo-ngokukodwa ekusetyenzisweni kwabantu.
Ngokwe-R yokuqala ("ukutshintshwa"), ngokuthelekisa (Kramer, Guillory, and Hancock 2014) ngokomzimba (Kramer, Guillory, and Hancock 2014) kunye nokuvavanya kwimeko yemvelo (Lorenzo Coviello et al. 2014) unikeza izifundo ezithile ngokuphathelele ukurhweba okubandakanyekayo ukuhamba ukusuka kumalinge ukuya kwizilingo zendalo (kunye nezinye iindlela ezifana nokufanisa ezama ukuzama ukulinganisa kwi-data engeyiyo yokuhlola; funda isahluko 2). Ukongeza kwiinzuzo zokuziphatha, ukutshintsha ukusuka kwisilingo ukuya kwizifundo ezingezizo zovavanyo kwenza abaphandi bafunde unyango abangenakukwazi ukuyisebenzisa. Lezi zibonelelo eziphathekayo kunye nezokungena ziza ngeendleko, nangona kunjalo. Ngovavanyo olusemgangathweni abaphandi banakho ukulawula okungaphantsi kwezinto ezifana nokuqashwa kwabathathi-nxaxheba, ukuchithwa kwamanani, kunye nobume bonyango. Ngokomzekelo, umlinganiselo omnye wemvula njengonyango kukuba kokubili ukwandisa ubuchule kwaye kunciphise ukungabikho komthetho. Kwimeko yophando, nangona kunjalo, uKramer kunye noogxa babenakho ukulungisa utshintsho kunye nokungahambisani nokuzimela ngokuzimeleyo. Indlela ethile esetyenziswa Lorenzo Coviello et al. (2014) wachazwa ngakumbi L. Coviello, Fowler, and Franceschetti (2014) . Ukwenza isingeniso kwiintlobo eziguqukayo, yindlela ekusetyenziswa ngayo Lorenzo Coviello et al. (2014) , bona i- Angrist and Pischke (2009) (engekho mthethweni) okanye i- Angrist, Imbens, and Rubin (1996) (ngaphezulu ngokusemthethweni). Ukuhlola okungaqinisekiyo kweempawu ezibonakalayo, jonga Deaton (2010) , kunye nesingeniso kwiintlobo ezinokusetyenziswa kwezixhobo ezinobuthakathaka (imvula iyisisithakathakathaka), bona u- Murray (2006) . Ngokuqhelekileyo, isingeniso esilungileyo kwimvavanyo yendalo yenziwa Dunning (2012) , ngoxa Rosenbaum (2002) , ( ??? ) , kunye Shadish, Cook, and Campbell (2001) inikeza iingcamango ezintle malunga nokuqikelela iziphumo ezibangelwa ngaphandle kwezilingo.
Ngokwesibini R ("ukulungiswa"), kukho i-trade-offs xa kuthethwa ngokutshintsha i-Design of Contemporary Heart emotionally blocking posts to increase posts. Ngokomzekelo, kungenjalo ukuba ukuphunyezwa kobugcisa beendaba zeendaba kuyenza kube lula ukwenza uvavanyo apho izithuba zivaliwe khona kunokuba ziphakanyisiwe (phawula ukuba ukuzama ukukhusela izithuba kungaqaliswa njengoluhlu oluphezulu kwenkqubo ye-News Feed ngaphandle kwesidingo sokutshintshwa kwenkqubo ephantsi). Ngokwenzululwazi, nangona kunjalo, ingcamango ebhekiswe yile mvavanyo ayizange icacise ngokucacileyo ukuyila komnye. Ngelishwa, andiyazi ukuba uphando olungaphambili malunga neempawu ezinxulumene nokukhusela nokukhuphula umxholo kwi-News Feed. Kwakhona, andizange ndibonwe uphando oluninzi malunga nokucocwa kweyeza ukwenzela ukuba bangabi nengozi; Ngaphandle kwe- B. Jones and Feamster (2015) , B. Jones and Feamster (2015) imeko yokulinganiswa kwe-Intanethi (isihloko esixoxisana ngayo kwisahluko 6 ngokumalunga (Burnett and Feamster 2015; Narayanan and Zevenbergen 2015) ).
Ngokomgangatho wesithathu R ("ukunciphisa"), iintetho ezintle zokuhlalutya amandla emveli zinikezwa Cohen (1988) (incwadi) kunye Cohen (1992) (inqaku), ngoxa Gelman and Carlin (2014) banikela ngombono ohlukileyo. Ii-covariate zangaphambili zonyango zingabandakanywa kwi-design kunye nokuhlalutya kwinqanaba lezilingo; Isahluko 4 Gerber and Green (2012) sinika isingeniso esihle kwiindlela zombini, kunye Casella (2008) inikeza unyango olunzulu. Iinkqubo ezisetyenziselwa le ngcaciso engaphambi kokunyanga kwi-randomization zibizwa ngokuba zivaliwe okanye ziyi-designed experimental designs (igama lesiqhelo lisetyenziswanga ngokubanzi kulo lonke uluntu); ezi ndlela zihlobene ngokuthe ngqo Higgins, Sävje, and Sekhon (2016) kwisahluko 3. Bona Higgins, Sävje, and Sekhon (2016) malunga nokusetyenziswa kwezi mveliso kwizilingo ezinkulu. Ii-covariate zangaphambili zonyango zingabandakanywa kwisigaba sokuhlalutya. McKenzie (2012) uhlola indlela eyahlukileyo-eyahluke ngayo ukuhlalutya ukuhlolwa kwimihlaba ngokubanzi. Bona Carneiro, Lee, and Wilhelm (2016) ngokubanzi malunga nokurhweba phakathi kweendlela ezahlukeneyo zokunyusa ngokuchanekileyo kwiingqikelelo zempatho zonyango. Ekugqibeleni, xa usenza isigqibo sokuba uzame ukuquka ii-covariates zangaphambili kunyango okanye uhlalutyo (okanye zombini), kukho izinto ezimbalwa zokuqwalasela. Kwimeko apho abaphandi bafuna ukubonisa ukuba "abadobi" (Humphreys, Sierra, and Windt 2013) , ukusebenzisa ii-covariates zangaphambili kwindlela yokuyilwa kunokuba luncedo (Higgins, Sävje, and Sekhon 2016) . Kwiimeko apho abathathi-nxaxheba befika ngokulandelelana, ngokukodwa ukuhlolwa kwimihlaba ye-intanethi, ukusebenzisa ulwazi lwephambi kwonyango kwinqanaba lokuyilwa kunokuba nzima kunemeko; ubone, umzekelo, Xie and Aurisset (2016) .
Kufanelekile ukukongeza i-intuition malunga nokuba kutheni indlela eyahlukileyo-eyahlukileyo inokusebenza ngokugqithiseleyo kunokubahluko phakathi kweyodwa. Iziphumo ezininzi ze-intanethi zihluke kakhulu (jonga umzekelo, RA Lewis and Rao (2015) kunye Lamb et al. (2015) ) kwaye zizinzile ngokuhamba kwesikhathi. Kule meko, amanqaku okutshintsha aya kuba neentlobo ezincinci, ukwandisa amandla ovavanyo lokubala. Esinye isizathu sokuba le ndlela ingasetyenziswanga ngokuphindaphindiweyo kukuba ngaphambi kwexesha ledijithali, kwakungaqhelekanga ukuba neziphumo zonyango lwangaphambili. Indlela engakumbi yokucinga ngale ndlela kukucinga ukuzama ukulinganisa ukuba isenzo esithile sokwenza umzimba silahlekelwa ngumzimba. Ukuba ufumana indlela eyahlukileyo-in-means, uqikelelo lwakho luya kuba nokuhlukahluka okubangelwa ukuhluka kwizinto eziphakamileyo kubemi. Ukuba wenza indlela eyahlukileyo-eyahlukileyo, nangona kunjalo, ukuhlukahluka ngokwemvelo kwiisisindo kususwe, kwaye unokukwazi ukubona ngokulula ukumahluko obangelwa unyango.
Ekugqibeleni, ndandicinga ukongeza i-R yesine: "ukuphindaphinda". Okokuthi, ukuba abaphandi bazifumanisa ngolwazi olungakumbi kunokuba badinga ukulungisa umbuzo wabo wophando wangaphambili, kufuneka bavuselele kwakhona idatha ukuze babuze imibuzo emitsha. Ngokomzekelo, cinga ukuba iKramer kunye noogxa basebenzise umqikelelo-hlukene-hlukene kwaye bazifumanisa ngokwedatha engaphezulu kunokuba befuna ukujongana nombuzo wabo wophando. Esikhundleni sokungasisebenzisi idatha ngokubanzi, banokufunda ubuninzi befuthe njengomsebenzi wentsholongwane yengqondo yangaphambili. Kanye Schultz et al. (2007) yabona ukuba impembelelo yonyango yayahlukileyo kubasebenzisi abasebenzisa ukukhanya kunye nabanzima, mhlawumbi imiphumo yeendaba zeendaba ihluke kubantu ababeselindele ukuthumela imiyalezo evuyayo (okanye edabukisayo). Ukuphindaphinda kungaholela "ekulobeni" (Humphreys, Sierra, and Windt 2013) kunye ne-"p-hacking" (Simmons, Nelson, and Simonsohn 2011) , kodwa ezi (Simmons, Nelson, and Simonsohn 2011) nokudibanisa ingxelo (Simmons, Nelson, and Simonsohn 2011) , ukubhalisa kwangaphambili (Humphreys, Sierra, and Windt 2013) , kunye nezindlela zokufunda ngomatshini ezizama ukuphepha ukugqitha.