2.4.3.2 Matching

Matching hanga faaauraa ataahua na roto i te tapahi atu take.

Ka taea e faaauraa ataahua haere mai i rānei randomized whakahaeretia ngā ngā tūturu ranei. Ko, i reira e rave rahi āhuatanga te wahi e kore e taea e koe te whakahaere i te whakamātau pai, me te kore i te natura whakaratohia he whakamātau tūturu. I roto i enei tautuhinga, ki te ara pai te waihanga te ōrite te faaauraa ataahua. I roto i te ōrite, titiro te kairangahau i roto i te raraunga kore-whakamātau ki te waihanga o te iwi e te hunga rite anake kua riro taua tetahi te maimoatanga takirua, a kahore tetahi e. I roto i te tukanga o te ōrite, e mau tapahi hoki kairangahau; e ko, whakareretanga take te wahi i reira he kore noa iho kitea. Ko te kupu, tenei tikanga e kia atu tika huaina ōrite-a-tapahi, engari ka piri ahau ki te wā tuku iho: ōrite.

He tauira ataahua o te kaha o ōrite rautaki ki nui puna raraunga kore-whakamātau haere mai i te rangahau i runga i kiritaki whanonga e Liran Einav me hoa (2015) . Einav me hoa i hiahia i roto i auctions tango wahi i runga i eBay, a i roto i te whakaahua ratou mahi, ka arotahi ahau i runga i tetahi āhuatanga ngā: te pānga o te mākete utu tīmata i runga i ngā putanga mākete, pērā i te utu hoko i te tūponotanga o te hoko ranei.

Te ara tino kuware ki te whakahoki i te pātai e pā ana ki te pānga o te utu tīmatanga i runga i te utu hoko e kia ki te tātai noa te utu whakamutunga mo auctions ki utu tīmatanga rerekē. e kia pai tenei huarahi, ki te hiahia noa koe ki te matapae i te utu hoko o te tūemi i homai e kua maka ki runga ki eBay ki te utu tīmatanga i homai. Otiia, ki te koutou pātai ko te mea ko te pānga o tīmata utu i runga i ngā putanga mākete tenei huarahi e kore e mahi i te mea e kore te mea e hāngai ana i runga i faaauraa ataahua; nga auctions ki utu tīmatanga raro kia rerekē tino i auctions ki utu tīmatanga teitei (hei tauira, kia waiho ratou mo momo rerekē o te taonga ngā momo rerekē o te kaihoko ranei).

Ki te mea ko koe āwangawanga kē e pā ana ki te hanga whakataurite ataahua, ai te tīpoka koe te huarahi kuware, me te whakaaro rere i te whakamātau mara i reira e hoko koe i te tauwhāiti tūemi-mea, he karapu-ki korowha he huinga pūmau o te mākete tawhā mea-, kaipuke free, mākete tuwhera mō te rua wiki, me ētahi atu-engari ki matapōkeretia whakaturia utu tīmata. Na roto i te whakatairite i te putanga mākete hua, e whakahere tenei mara whakamātau te inenga rawa mārama o te pānga o tīmata utu i runga i te utu hoko. Ko, tenei inenga e tono anake ki tetahi hua ngā me whakatu o ngā tawhā mākete. ai kia nga hua rerekē, hei tauira, mō ngā momo rerekē o te hua. Kahore he ariā kaha, he mea uaua ki te hīkaro i tenei whakamātau kotahi te whānuitanga ki tonu i te ngā taea e taea kua rere. I tua atu, he feunga utu e e te mea infeasible ki rere nui o ratou ki runga ki te taupoki ana i te wāhi tawhā katoa o ngā hua, me ngā momo mākete ngā mara.

I roto i te rerekē ki te huarahi kuware me te huarahi whakamātautau, tangohia Einav me hoa he toru huarahi: ōrite. Te taea matua o to ratou rautaki ko ki te ite mea rite ki ngā mara e kua tupu kē i runga i eBay. Hei tauira, Whakaahua 2.6 whakaatu etahi o nga rārangi 31 mo rite te karapu-te korowha taua Taylormade Pūtahu 09 Driver-te hokona e rite te taua seller- "budgetgolfer". Heoi, enei rārangi whai āhuatanga paku rerekē. Kotahi tekau ma tahi o ratou whakahere te kaiarataki mo te utu i whakaritea o $ 124,99, i te tahi atu 20 He auctions ki ngā rā mutunga rerekē. Ano, te rārangi i rerekē utu kaipuke, rānei $ 7.99 ranei $ 9.99. I roto i te mau parau te tahi atu, he mea rite ki te "budgetgolfer" Kei te rere ngā mo nga kairangahau.

Nga rārangi o te Taylormade Pūtahu 09 Driver e hokona e "budgetgolfer" e tetahi tauira o te huinga āu o rārangi, te wahi kei te hokona i te tūemi taua tangohia e te kaihoko i taua tangohia, engari ia wa ki ngā āhuatanga paku rerekē. I roto i nga rākau nui o eBay reira e mooni rau o nga mano o huinga āu whai wāhi mirioni o rārangi. Ko te kupu, nui atu i te whakatairite i te utu whakamutunga mo auctions katoa i roto i te utu tīmatanga hoatu, meinga Einav me hoa whakataurite i roto i ngā huinga ki āu. Roto i te tikanga ki te whakakotahi i ngā hua i te fakafehoanaki roto enei rau o nga mano o ngā huinga āu, Einav me hoa anō-faaite i te utu tīmata me te utu whakamutunga i roto i ngā o te uara tohutoro o ia tūemi (hei tauira, i ona utu hoko toharite). Hei tauira, ki te mea he uara tohutoro o $ 100 te Taylormade Pūtahu 09 Driver (e hāngai ana i runga i ona hoko), ka e kia faaite te utu tīmatanga o $ 10 rite 0.1 me te utu whakamutunga o $ 120 e kia faaite rite 1.2.

Whakaahua 2.6: He tauira o te huinga āu. Ko te karapu tangohia taua korowha (he Taylormade Pūtahu 09 Driver) i hokona e te taua tangata tangohia ( "budgetgolfer") i tenei, engari etahi o enei hoko whakamana i ngā āhuatanga rerekē (hei tauira, rerekē utu tīmata). Figure tangohia i Einav et al. (2015) .

A haamana'o na i hiahia i roto i te pānga o te utu tīmatanga i runga i ngā putanga mākete Einav me hoa. Tuatahi, mā te whakamahi i regression rārangi tata ratou e teitei utu tīmatanga whakaiti i te tūponotanga o te hoko, a kia whakanui ake teitei utu tīmatanga te utu hoko whakamutunga, here i runga i te hoko e puta ana. E ratou, enei tata-nei e Pine i runga i ngā hua katoa, me te amo i te pānga rārangi i waenganui i te utu tīmatanga me te whakamutunga e kore putanga e-e ngā katoa. Engari, te whakamahi i hoki Einav me hoa te rahi nui o ratou raraunga ki te whakatau tata i te whānuitanga o ngā kitenga mohio ake. Tuatahi, i hanga Einav me hoa enei tata motuhake hoki ngā tūemi o utu rerekē, me te kahore te whakamahi i regression rārangi. kitea e ratou e ia i te hononga i waenganui i te utu tīmatanga me te tūponotanga o te hoko he rārangi, te hononga i waenganui i te utu tīmatanga me te utu hoko ko mārama rārangi-kore (Figure 2.7). I roto i ngā, no te tīmata utu i waenganui i te 0.05 me te 0.85, he iti rawa pānga i runga i te utu hoko, he kitenga i ngaro i roto i te tātari i riro he hononga rārangi oti te utu tīmata.

Feruri 2.7: Te hononga i waenganui i mākete utu tīmatanga me te tūponotanga o te hoko (mahue rōpū) me te utu hoko (rōpū matau). He pakeke te hononga rārangi i waenganui i te utu tīmatanga me te tūponotanga o te hoko, engari i reira he he hononga kore-rārangi i waenganui i te utu tīmatanga me te utu hoko; hoki tīmata utu i waenganui i te 0.05 me te 0.85, he iti rawa pānga i runga i te utu hoko i te utu tīmata. I roto i te wā e rua, he waiwai motuhake o uara tūemi nga hononga. Ēnei kauwhata uri piki 4a me 4b Einav et al. (2015) .

Tuarua, nui atu i te wawaenga mo tūemi katoa, te whakamahi i hoki Einav me hoa te tauine nui o ratou raraunga ki te whakatau tata i te pānga o te utu tīmata hoki 23 kāwai rerekē o ngā tūemi (hei tauira, mōkai kai, hikohiko, me Etahi hākinakina) (Figure 2.8). whakaatu ēnei whakatau tata e mo ake motuhake tūemi-pērā i Etahi-tīmatanga utu he pānga iti i runga i te tūponotanga o te hoko, me te pānga nui i runga i te utu hoko whakamutunga. I tua atu, no te tūemi-pērā atu commodified rite DVD me ataata-te utu tīmatanga e tata kahore pānga i runga i te utu whakamutunga. I roto i te mau parau te tahi atu, he toharite e fakatahai hua i 23 kāwai rerekē o ngā tūemi huna mōhiohio nui e pā ana ki te rerekētanga i waenganui i enei tūemi.

Feruri 2.8: whakakitea Hua tata i ia kāwai takitahi; te ira mārō i roto i te tata mō ngā kāwai katoa nga repo tahi (Einav et al. 2015, Table 11) . whakaatu ēnei whakatau tata e mo ake motuhake tūemi-pērā i Etahi-te utu tīmatanga he pānga iti i runga i te tūponotanga o te hoko (x-tuaka) me te pānga nui i runga i te utu hoko whakamutunga (y-tuaka).

Ahakoa, ki te kahore e koe tino hiahia i roto i auctions runga i eBay, whai koe ki te faahiahia i te ara e whakaatu 2.7 me Figure 2.8 tuku te taonga māramatanga o eBay atu tata inenga rārangi ohie e amo hononga rārangi, me te whakakotahi maha ngā kāwai rerekē o ngā tūemi. Ēnei whakatau tata olopoto atu whakaatu te mana o te ōrite i roto i te raraunga nui; e kua enei whakatau tata i taea, kahore he maha nui o ngā parae, e pai i prohibitively utu kua.

O te akoranga, kia whai tatou iti maia i roto i nga hua o tetahi ako ngā ōrite atu i pai matou i roto i nga hua o te whakamātau rite. A, no te aromatawai i te hua i tetahi ako mo, reira e rua āwangawanga nui. Tuatahi, tatou ki te mahara e nehenehe ia tatou ia te whakarite faaauraa tika i runga i nga mea i whakamahia mō te ōrite anake. I roto i to ratou hua matua, Einav me hoa i tangohia ōrite i runga e wha āhuatanga: tau kaihoko ID, kāwai tūemi, taitara tūemi, me te taitararoto. Ki te he rerekē i roto i ara kihai i i whakamahia mo te ōrite, e taea te hanga i tētahi whakarite taurite nga tūemi. Hei tauira, ki te "budgetgolfer" tuku iho utu mō te Taylormade Pūtahu 09 Driver i roto i te hotoke (ina e iti rongonui karapu korowha), ka taea e kitea i te reira e arahi raro utu tīmata ki te raro utu whakamutunga, ina i roto i te meka e riro te artifact o tau tenei rerekētanga i roto i te tono. Roto i te whānui, i te huarahi pai ki tenei raruraru te mea ki te kia tamata maha momo rerekē o te ōrite. Hei tauira, Einav me hoa faahiti ratou tātaritanga wahi huinga ki āu ngā tūemi runga i te hoko i roto i te tau kotahi, i roto i te marama kotahi, a contemporaneously. Te hanga i te matapihi wa kita heke te maha o ngā huinga āu, engari whakaiti āwangawanga e pā ana ki te rerekētanga kaupeka. Aua'e, kitea ratou e he tonu e enei huringa i roto i te paearu ōrite hua. I roto i te tuhinga ōrite, i te nuinga o faaite tenei momo o te āwangawanga i roto i ngā o observables me unobservables, engari te whakaaro matua ko te tino e te hanga kairangahau faaauraa ataahua i runga i te āhuatanga e whakamahia ana i roto i te ōrite anake.

te rua o te āwangawanga nui, no te whakamārama i ngā hua ōrite ko e tono anake ratou ki raraunga āu; e kore ratou e tono ki te take e kore e taea te ki āu. Hei tauira, mā te whāiti ratou rangahau ki ngā tūemi e i rārangi maha Einav me hoa e arotahi i runga i kaihoko ngaio, me te āhua-ngaio. Ko te kupu, ka whakamārama i enei fakafehoanaki tatou me mahara e tono anake ratou ki tenei huinga o eBay.

Matching Ko te rautaki kaha mō te te kimi whakataurite ataahua i roto i huinga nui. Ki maha kaipūtaiao pāpori, mana'o ōrite rite rua-pai ki ngā, engari e ko te whakapono e kia whakahoungia, paku. Matching i roto i te raraunga nui ai kia pai atu i te maha iti o ngā mara ina: he nui 1) heterogeneity i roto i ngā pānga me 2) i reira he observables pai mō te ōrite. Ripanga 2.4 whakarato etahi atu mau hi'oraa o te pehea ōrite taea te whakamahi ki te puna raraunga nui.

I roto i te mutunga, he kino huarahi kuware ki tata pānga causal i raraunga kore-whakamātau. Heoi, ngā rautaki mō te hanga tata causal e takoto haere te auroa i kaha ki ngoikore, me kairangahau taea ite faaauraa ataahua i roto i raraunga kore-whakamātau. Te tupu o nga wa katoa-i runga i, ngā pūnaha raraunga nui faarahi to tatou kaha ki te whakamahi i tōtika rua tikanga ngā: ngā māori, me te ōrite.