2.4.3 Approximating kuedza
Tinogona kuongorora zvidzidzo zvatisina kana zvisingagoni kuita. Nzira mbiri dzinonyanya kubatsirwa nehurukuro huru yemadhina inowanzoedza nekuenzanisa.
Zvimwe zvinokosha zvezvesayenzi uye zvematongerwo enyika zvinokonzera. Semuenzaniso, chii chinokonzera chirongwa chekudzidzisa basa pamubairo? Mumwe muongorori achiedza kupindura mubvunzo uyu angafananidza nemari yevanhu vakanyora kuti vadzidzise kune avo vasina. Asi zviyero zvakasiyana zvakadini mumubairo pakati pemapoka aya ndezvikonzero zvekudzidziswa uye zvakadini nekuda kwekusiyana kwemaonero evanhu pakati pevanhu vanyoresa uye avo vasingaiti? Uyu mubvunzo wakaoma, uye mumwe chete hausi kuenderera mberi nemamwe deta. Mune mamwe mazwi, kunetseka pamusoro pezvinogona kuitika zvinopesana zvinokonzera pasinei nokuti vangani vashandi vari munharaunda yako.
Mune mamiriro ezvinhu mazhinji, nzira yakasimba yekufungidzira kuti chinokonzerwa nekurapa kwakadai sei, sekudzidzira basa, ndechokuita tsananguro inongorongedzwa zvakarongeka apo muongorori anongoronga kurapa kune vamwe vanhu kwete vamwe. Ndichatsvaga chitsauko chechina chekuedza, saka tarira ndichaenda kune dzimwe nzira mbiri dzinogona kushandiswa nedzimwe dzisiri nyaya yekuedza. Nzira yekutanga inofanirwa nekutsvaga chimwe chinhu chiri kuitika munyika iyo zvese (kana kuti zvishoma nezvishoma) inopa kurapa kune vamwe vanhu uye kwete vamwe. Sangano rechipiri rinoenderana nekuenzanisa nenyaya isiri yekuedza mukuedza kubhadharira kusawirirana kwevaya vakaita uye vasina kugamuchira kurapwa.
Munhu anokakavara angatora kuti maitiro aya ose anofanira kudziviswa nokuti anoda kufunga kwakasimba, mafungiro akaoma kuongorora uye kuti, mukuita, anowanzoputswa. Nepo ini ndinonzwira tsitsi kudai, ndinofunga kuti inopfuurira kure. Icho chokwadi ndechechokwadi kuti zvakaoma kutendeseka nekugadzirisa kuenzanisa kwekuenzanisa kubva kune zvisiri nyaya yekuedza, asi handifungi kuti zvinoreva kuti hatifaniri kumboedza. Kunyanya, nzira dzisiri dzedzidzo dzinogona kubatsira kana kugadziriswa kwezvigadziro kunokudzivirira kubva pakuitisa kuedza kana kana zvipingamupinyi zvetsika zvinoreva kuti haudi kutarisira kuedza. Uyezve, nzira dzisiri dzedzidzo dzinogona kubatsira kana iwe uchida kushandisa zvinyorwa zvatovepo kuti ugadzire kuongororwa kwakaitwa nemaitiro.
Kusati kwaenderera mberi, zvakakoshawo kuziva kuti kugadzira chinokonzera ndechimwe chezvinhu zvakaoma zvikuru mukutsvakurudza kwevanhu, uye imwe inogona kutungamirira mukukakavadzana kukuru uye mupfungwa. Mukutsvaga, ini ndichapa tsanangudzo yezvakanaka zveimwe neimwe nzira kuitira kuti tive nekugadzirisa pamusoro payo, ipapo ini ndicharondedzera zvimwe zvezvinetso zvinomuka kana uchishandisa nzira iyo. Mamwe mashoko pamusoro pega nzira imwe neimwe inowanikwa mune zvigadzirwa pakupera kwechitsauko chino. Kana ukaronga kushandisa imwe yemitoo iyi mukutsvakurudza kwako, ndinokurudzira zvikuru kuverenga imwe yemabhuku akawanda anonyanya kunaka pamusoro pezvinyorwa zvishoma (Imbens and Rubin 2015; Pearl 2009; Morgan and Winship 2014) .
Imwe nzira yekuita zvinokonzerwa nekufungidzira kubva kune zvisiri nyaya yekuedza ndeyokutsvaga chiitiko chakangoerekana chagovera kurapa kune vamwe vanhu kwete kune vamwe. Aya mamiriro ezvinhu anonzi kuedza kwepanyama . Imwe mienzaniso yakajeka yekuedza kwepanyama inouya kubva pakutsvakurudza kwaJoshua Angrist (1990) kuenzanisa migumisiro yemabasa ehondo pamariro. Munguva yehondo muVietnam, United States yakawedzera hukuru hwemauto ayo ehondo kuburikidza nehurongwa. Kuti asarudze kuti vagari vemo vaizoendeswa kushanda, hurumende yeUnited States yakabata lottery. Zuva roga roga rokuberekwa rakanyorwa pamapepa, uye, sezvinoratidzwa muchitsauko 2.7, zvikamu izvi zvepapepa zvakasarudzwa imwe panguva imwechete kuti vaone kurongeka kwaiitwa nevarume vaduku kuti vashumire (vasikana vechidiki vakanga vasingadi kusvika kumusangano). Kubva pamigumisiro, varume vakaberekwa musi waSeptember 14 vakadanidzwa kutanga, varume vakaberekwa musi waApril 24 vainzi wechipiri, nezvimwe zvakadaro. Pakupedzisira, mune iyi lottery, varume vakazvarwa mumazuva makumi mapfumbamwe nemashanu akasiyana-siyana vakanyorwa, asi varume vakaberekwa mumazuva 171 vakanga vasina.
Mufananidzo 2.7: Congress Congress Alexander Pirnie (R-NY) anotora kapule yekutanga yeSelective Service draft musi waDecember 1, 1969. Joshua Angrist (1990) akabatanidza kukora bhoraji nemari yekuwana mari kubva kune Social Security Administration kuenzanisa kushanda kwebasa rechiuto pamari. Uyu muenzaniso wekutsvakurudza uchishandisa chiitiko chechisikigo. Mhedziso: US Selective Service System (1969) / Wikimedia Commons .
Kunyange zvazvo zvingave zvisingaonekwi nokukurumidza, kukora kotaji kunobatanidza zvakaenzana nekuongororwa kwakaongororwa kwakaongororwa: mumamiriro maviri aya, vatori vechikamu vanongororwa kuti vawane kurapwa. Kuti awane zvinoitwa nemutachiona uyu, Angrist akatora nguva yakawanda-pane huru data system: US Social Security Administration, iyo inounganidza mashoko pamusoro pemari yose yeAmerica kubva kubasa. Nokubatanidza ruzivo pamusoro pevanhu vaisarudzwa musarudzo yekodha nemari yekuwana iyo yakaunganidzwa muhurumende yehutori hwemashoko, Angrist akagumisa kuti mhindu yeveterans yaiva yega 15% iri pasi pemari yevanenge vasiri veterans vakafanana.
Sezvo muenzaniso uyu unoratidza, dzimwe nguva hutano hwevanhu, zvematongerwo enyika, kana masimba hunoita zvirwere nenzira inogona kuenzaniswa nevatsvakurudzi, uye dzimwe nguva migumisiro yezvirapa izvi inotorwa nguva dzose-pane hurukuro yezvinyorwa. Nzira iyi yekutsvakurudza inogona kuiswa muchidimbu sezvinotevera: \[\text{random (or as if random) variation} + \text{always-on data} = \text{natural experiment}\]
Kuenzanisira urongwa uhwu muzera rema digital, regai tiongorore kuongorora naAlexandre Mas uye Enrico Moretti (2009) vakaedza kuenzanisa kuitika kwekushanda pamwe chete nevamwe vanobudirira kune zvibereko zvekushanda. Usati waona zvigumisiro, zvakakosha kuti uone kuti pane zvinotarisana zvinopesana zvaungave nazvo. Kune rumwe rutivi, unogona kutarisira kuti kushanda nevashandi vanobudirira kunotungamirira mushandi kuti awedzere kubereka kwaanoita nekuda kwevezera rako. Kana, kune rumwe rutivi, unogona kutarisira kuti kuva nevezera rakashanda kunogona kutungamirira mushandi kuti ashevedze nokuti basa richaitwa nevezera rake zvakadaro. Nzira yakanyatsojeka yekudzidza maitiro ekuenzanisa pakubudirira kwaizova kuongororwa kusinganzwisisiki kunoitwa nevashandi vanongotarirwa kushanduka nevashandi vehutano hwakasiyana-siyana uye zvino zvibereko zvinogadzirwa zvinowanikwa kune vose. Vanotsvakurudza, zvisinei, havagadziri purogiramu yevashandi mubhizimusi chero ripi zvaro, uye saka Mas uye Moretti vaifanira kutenderera pane kuedza kwechisikigo kune vashandi vari muchitorosi.
Munzvimbo iyi yepamupurisa, nekuda kwenzira iyo kugadzirisa kwaive kuitwa uye nzira iyo shizha yakaputika, umwe neumwe wekashiashi aiva nevashandi vakasiyana-siyana panguva dzakasiyana dzezuva. Uyezve, mune imwe chikafu chechikafu, basa revachengeti rakanga risingapindirani nehuwandu hwevezera ravo kana kuti zvakabatikana nechitoro chacho. Mune mamwe mazwi, kunyange zvazvo kuronga kwevashandi vasati vasarudzwa nejotori, zvakanga zvakaita sokuti vashandi dzimwe nguva vaisarudzwa kuti vashande nepamusoro (kana kuti pasi) kubudisa vezera. Nenzira yakanaka, chiremba ichi chaivawo ne-digital-age checkout system yakaona zvinhu izvo cashier imwe neimwe yakanga ichiongorora nguva dzose. Kubva pane ino yekutora data, Mas uye Moretti vakakwanisa kugadzira zvakananga, munhu, uye nguva dzose-pachiyero chekubudirira: nhamba yezvinhu zvakarongwa pamusi wechipiri. Kubatanidza zvinhu izvi zviviri-kuchinja kwezvakangoita muhutano hwevezera uye nguva dzose-pachiyero chekubudirira-Mas uye Moretti vanofungidzira kuti kana muchengeti akapiwa vashandi vashandi vaive 10% vanobudirira zvikuru kupfuura yevhareji, kubereka kwake kwaizowedzera ne 1.5% . Uyezve, vakashandisa ukuru uye hupfumi hwezvinyorwa zvavo kuti vaongorore zvinhu zviviri zvinokosha: hutano hwakakosha hwechiitiko ichi (Nokuti ndeapi mavashandi ingirozi huru?) Uye nzira dzinoita kuti zvivepo (Sei kuve nehuwandu hwekuita zvezera hunotungamirira kukura kwepamusoro?). Tichadzoka kune izvi zviviri zvakakosha-hutano hwehutano hwekurapa uye nzira-muchitsauko 4 apo patinokurukura kuongororwa zvakadzama.
Kuronga kubva pane izvi zvidzidzo zviviri, tafura 2.3 inopfupisa zvimwe zvidzidzo zvine chimiro chakafanana: kushandisa nguva dzose-pane dhiyabhorosi nzvimbo yekuyera maitiro emamwe maitiro akasiyana-siyana. Mukuita, vatsvakurudzi vanoshandisa nzira mbiri dzakasiyana dzekuwana kuedza kwezvisikwa, zvose zvingabereka zvibereko. Vamwe vanotsvakurudza vanotanga ne-nguva dzose-pane data uye vanoongorora zviitiko zvisina kuitika munyika; vamwe vanotanga chiitiko chisina kuitika munyika uye vachitsvaga zvinyorwa zvemashoko zvinotora zvayo.
| Kutsvaga kwakanyanya | Chinhu chekuedza kwepanyama | Nguva dzose-pane dhiyabhorosi | Dheuteronomio |
|---|---|---|---|
| Kuve nevezera rako pane zvinobudirira | Kuronga hurongwa | Checkout data | Mas and Moretti (2009) |
| Shamwari yekuumba | Hurricanes | Phan and Airoldi (2015) | |
| Kupararira kwemanzwiro | Rain | Lorenzo Coviello et al. (2014) | |
| Peer-to-peer inoshandiswa mune zvemari | Kudengenyeka kwenyika | Mobile money data | Blumenstock, Fafchamps, and Eagle (2011) |
| Kuzvidzivirira kwehutano hwako | 2013 hurumende yeU.S. kuvhara | Mari yehupfumi data | Baker and Yannelis (2015) |
| Hurongwa hwezvehupfumi hwehutungamiri hurumende | Various | Browsing data ku Amazon | Sharma, Hofman, and Watts (2015) |
| Migumisiro yekushungurudzika pavana vasina kuberekwa | 2006 Israel-Hezbollah hondo | Nhoroondo dzekuzvarwa | Torche and Shwed (2015) |
| Kuverenga maitiro pa Wikipedia | Zvakazarurirwa Snowden | Wikipedia logs | Penney (2016) |
| Kuve nevezera rako pamusangano | Weather | Fitness track trackers | Aral and Nicolaides (2017) |
Mukukurukurirana zvakanyanya pamusoro pekuedza kwezvisikwa, ndakasiya imwe pfungwa inokosha: kubva kune zvakasikwa izvo zvaunopa pane zvaunoda dzimwe nguva zvinganyengera. Ngatidzokerei muenzaniso wekuVietnam muenzaniso. Muchiitiko ichi, Angrist aifarira kuenzanisa kushanda kwebasa rechiuto pamubhadharo. Zvinosuruvarisa, basa remauto rakanga risina kupiwa; pane iyo yakanga iri kunyorwa iyo yaive yakarongedzwa. Zvisinei, havasi vose vakanyorerwa vakashanda (pakanga pane zvakasiyana-siyana zvekuregererwa), uye kwete avo vose vakashanda vakanga vakanyorwa (vanhu vanogona kuzvipira kushanda). Nokuti kunyorwa kwaive kwakarongedzwa, mumwe mutsvakurudzi anogona kufungidzira kuitika kwekunyorwa kwevanhu vose mubhuku. Asi Angrist aisadi kuziva ruzivo rwekunyorwa; iye aida kuziva kuguma kwekushumira muuto. Kuti tive nekufungidzira uku, zvisinei, mamwe mafungiro uye matambudziko anodiwa. Kutanga, vatsvakurudzi vanofanira kufungidzira kuti nzira chete iyo kunyorwa yakagadziriswa inobhadharwa ndeyekuita basa remauto, kubvuma kunonzi kubviswa kwekuregererwa . Izvi zvinogona kunge zvisina kururama kana, somuenzaniso, varume vakanyorwa vakagara muchikoro kwenguva yakareba kuitira kuti vasazoshanda kana kana vashandi vakanga vasingakwanisi kubhadhara varume vakanyorwa. Nenzira yakawanda, kuregererwa kwekuregererwa kunonyanya kukoshesa, uye kazhinji kunonetsa kuongorora. Kunyange kana kuregererwa kwekuregererwa kwakarurama, hazvisakwanisi kuenzanisa kushanda kwebasa kuvanhu vose. Pane kudaro, zvinowanzoitika kuti vatsvakurudzi vanogona kungoyera kuitika kune chimwe chikamu chevarume vanonzi compliers (varume vanozoshanda kana vakanyorwa, asi (Angrist, Imbens, and Rubin 1996) kana vasinganyorwa) (Angrist, Imbens, and Rubin 1996) . Makambani, zvisinei, akanga asiri vanhu vokutanga vanofarira. Cherechedza kuti zvinetso izvi zvinomuka kunyange mumamiriro ezvinhu asina kuchena ehurongwa wehotera. Rimwe dambudziko rezvinetso rinomuka apo kurapwa hakusi kugoverwa nejaji yenyama. Somuenzaniso, muMas uye Moretti kudzidza kwevatengesi, mibvunzo yakawedzera inomuka pamusoro pekufungidzira kuti basa revezera rinonyanya kusarudzwa. Kana izvi zvingangove zvakaputsika zvakasimba, zvinogona kukanganisa maonero avo. Kuti apedzisire, kuedza kwepanyama kunogona kuva sarudzo yakasimba yekugadzirisa zviyero kubva kune zvisiri nyaya yekuedza, uye makuru makuru ezvinyorwa anowedzera kukwanisa kwatinoita pakuita zvidzidzo zvepanyama pazvinoitika. Zvisinei, zvinenge zvichitoda kutarisira kukuru-uye dzimwe nguva kufunga kwakasimba-kubva kune zvakasikwa zvakagadzirirwa kuwandisa kwaunoda.
Nzira yechipiri yandinoda kukuudza pamusoro pekugadzirisa zviyero kubva kune zvisiri nyaya yekuedza inobva pane kuwandisa kuchinja nenyaya dzisiri yekuedza mukuedza kubhadharira kukanganisa kwepakati pakati pevaya vakaita uye vasina kugamuchira kurapwa. Pane zvakawanda zvigadziriro zvakadaro zvinosvika, asi ini ndichaisa pfungwa pane imwe inonzi inofananidzwa . Mukufananidza, muongorori anotarisa kuburikidza nedzimwe nyaya dzisiri yekuedza kuti aumbe mapaundi evanhu akafanana kunze kwekuti iye akagamuchira kurapwa uye mumwe asina. Mukugadzira kufanana, vatsvakurudzi vari kunyanya kuchekerera ; ndiko kuti, kurasikirwa nenyaya apo pasina mutsara wakajeka. Nokudaro, iyi nzira yaizove yakanyatsodanwa kunyorerana-uye-kutema, asi ini ndichanamatirana nemutauro wechihedheni: kufanana.
Mumwe muenzaniso wesimba rekugadzirisa maitiro nemashoko makuru asingasviki epa data anobva pakutsvakurudza pamitemo yevatengi naLiran Einav uye vashandi pamwe navo (2015) . Vaive nehanya mune zvekutengeswa zviri kuitika paBay, uye mukutsanangura basa ravo, ndichafunga nezvekuita kwekutengeswa kwekutengeswa kwemutengo pamigumisiro yevekutsvaga, zvakadai semutengo wekutengesa kana mukana wekutengesa.
Nzira yakanakisisa yekufungidzira kuitika kwekutangira mutengo pamutengo wekutengesa kwaizove kungoverengera mutengo wekupedzisira wevashandisi neyekutanga kutengesa mutengo. Iyi nzira yaizova yakanaka kana iwe uchida kufanotaura mutengo wekutengesa wakapa mutengo wokutanga. Asi kana mubvunzo wako uchitaura nezvekuita kwemutengo wokutanga, ipapo nzira iyi haigoni kushanda nokuti haina kubva pakuenzanisa kwakanaka; iyo inotengeswa nemitengo yakadzika yokutanga inogona kunge yakasiyana zvikuru nevaya vane yepamusoro yemitengo (semuenzaniso, vanogona kunge vari marudzi akasiyana ezvimwe zvinhu kana kusanganisira mhando dzakasiyana dzevatengesi).
Kana iwe uchitoziva nezvezvinetso zvinogona kuitika paunenge uchitarisa matanho kubva pane zvisiri zvekuongorora, iwe unogona kudarika nzira yekusvibisa uye funga kutarisa mamiriro ekutsvaga kwaunogona kutengesa chimwe chinhu-chiti, girafu-gorofu-ine sekutsvaga mitemo-inoti, kutumira pasina uye auctiontion yakazarurirwa kwemavhiki maviri-asi nematambudziko anotanga kutangira. Nokuenzanisa migumisiro yemigumisiro inoguma, iyi shanduro yeruzivo yaizopa chiyero chakajeka chekuita kwekutangira mutengo pamutengo wekutengesa. Asi chiyero ichi chinongoshanda kune chimwe chigadzirwa uye sarudzo yemitengo. Migumisiro inogona kunge yakasiyana, somuenzaniso, kune marudzi akasiyana ezvigadzirwa. Pasina nharo yakasimba, zvakaoma kuwedzera kubva pane imwe yeruzivo kusvika kuhuwandu hwakazara hwezviitiko zvinogona kuitika. Uyezve, kuongorora kwenyika kunodhura zvakakwana kuti zvingave zvisingakwanisi kuita zvese zvaungada kuedza.
Kusiyana nemafungiro asina zivo uye anoedza, Einav nevanoshanda navo vakatora nzira yechitatu: kufanana. Kunyengedza kukuru muurongwa hwavo ndeyekuwana zvinhu zvakafanana neminda yekuedza izvo zvatoitika paBay. Somuenzaniso, chiitiko 2.8 chinoratidza zvimwe zvemashoko makumi matatu nematatu ekutsvaga gwaro regorofu-Taylormade Burner 09 Mutyairi-ari kutengeswa nemutengesi mumwechete- "bhaggolfer." Zvisinei, izvi zvinyorwa 31 zvine maitiro akasiyana zvakasiyana, zvakadai sokutanga mutengo, mazuva ekupedzisira, uye kutumira mari. Mune mamwe mazwi, zvakaita sokuti "bhaggolfer" iri kuedza kuongororwa kwevanotsvakurudza.
Aya mazita a Taylormade Burner 09 Mutyairi anotengeswa ne "budgetgolfer" ndeye muenzaniso wekufananidzwa kwezvinyorwa, apo izvo chaizvoizvo chinhu chiri kutengeswa nemutengesi chaiye, asi nguva imwe neimwe nezvimwe zvisizvo zvakasiyana. Mumatanda makuru eBay pane chaizvo zvemazana ezviuru zvakaenzaniswa zvinosanganisira mamiriyoni ezvinyorwa. Nokudaro, pane kuenzanisa mutengo wokupedzisira wezvinhu zvose zvakasarudzwa nemutengo wekutanga wakatanga, Einav nevanoshanda navo vanofananidza mukati mekuenzaniswa. Kuti uwirirane nemigumisiro kubva kuzvienzanisi mukati memazana ezviuru zvekuenzanisa, Einav nevanoshanda navo vakadzokorora zvakare mutengo wokutanga uye mutengo wokupedzisira maererano nehuwandu hwekutaridzirwa kwezvinhu zvose (semuenzaniso, mutengo waro wekutsvaga). Semuenzaniso, kana Taylormade Burner 09 Mutyairi aiva nekutaridzirwa kwe $ 100 (zvichienderana nekutengeserana kwayo), ipapo mutengo wokutanga we $ 10 ungaratidzwa se1 0.1 uye mutengo wokupedzisira we $ 120 se 1.2.
Mufananidzo 2.8: Muenzaniso wekuenzaniswa. Iyi ndiyo chaiyo iyo gorofu yemutambo (a Taylormade Burner 09 Driver) inotengeswa nomunhu chaiye ("budgetgolfer"), asi zvimwe zvekutengesa zvakaitwa pasi pemamiriro akasiyana-siyana (semuenzaniso, kusiyana kwekutanga kutengesa). Yakadzorerwa nemvumo kubva kuna Einav et al. (2015) , chiito 1b.
Yeuka kuti Einav nevamwe vaishanda navo vaifarira nezvekugadzirisa kwekutanga mutengo pamigumisiro yekutengeswa. Chokutanga, vakashandisa kugadziriswa kwemazuva ekufungidzira kuti kutsika kwepamusoro kwekutengesa kunoderedza mikana yekutengesa, uye iyo yakatanga kutengesa mitengo inowedzera mutengo wokupedzisira wekutengesa (maererano nekutengesa kunoitika). Nevamwe, izvi zvinofungidzirwa-izvo zvinorondedzera ukama hwakanaka uye zvinongororwa pamusoro pezvinhu zvose-hazvisi zvose zvinofadza. Zvadaro, Einav nevakashanda navo vakashandisa ukuru hwemashoko avo kuti vateerere maitiro akasiyana-siyana akaoma. Semuenzaniso, nekuenzanisa kuitika zvakasiyana kune zvakasiyana siyana zvakatanga kutengesa, vakawana kuti ukama pakati pekutangira mutengo uye mutengo wekutengesa hauna mutsara (chifananidzo 2.9). Kunyanya, pakutanga mutengo pakati pe 0.05 ne 0.85, mutengo wokutanga une zvishoma zvishoma pamutengo wekutengesa, kuwanikwa kwakange kusisipo zvachose nekuongorora kwavo kwekutanga. Uyezve, pane kuisa zvinhu pamusoro pezvinhu zvose, Einav nevanoshanda navo vanofungidzirwa kuti zvinokonzerwa nekutangira mutengo wezvikamu makumi maviri nemaviri zvezvinhu (semuenzaniso, zvigadzirwa zvemhuka, magetsi, uye zvemitambo memorabilia) (Mufananidzo 2.10). Izvi zvinongoratidzira zvinoratidza kuti zvimwe zvinhu zvakasiyana-zvakadai sekuyeuka-mutengo wekutanga zvine zvishoma zvingaita mukana wekutengesa uye nemigumisiro yakakura pamutengo wokupedzisira wekutengesa. Uyezve, kune zvimwe zvinhu zvakagadziriswa-zvakadai seDVD-mutengo wokutanga hauve wakakosha pamutengo wokupedzisira. Mune mamwe mazwi, muvhareji unobatanidza migumisiro kubva kumapoka 23 akasiyana ezvinhu anovanza kusiyana kukuru pakati pezvinhu izvi.
Mufananidzo 2.9: Ukama huri pakati pekutengeswa kwekutengeswa uye kutengesa kwekutengeswa (a) uye mutengo wekutengesa (b). Pano pane ukama huri pakati pekutangira mutengo uye mukana wokutengesa, asi ukama hwenheyo pakati pekutangira mutengo uye mutengo wekutengesa; nokuda kwekutangira mutengo pakati pe 0.05 ne 0.85, mutengo wokutanga une zvishoma zvishoma pamutengo wekutengesa. Muzviitiko zvose izvi, ukama huri hwekuzvimiririra pane chinhu chinokosha. Yakashandiswa kubva kuna Einav et al. (2015) , zvikamu 4a uye 4b.
Mufananidzo 2.10: Inofanirwa kubva kune imwe neimwe yezvinhu; dhidhiyo yakasimba ndiyo kuongororwa kwemarudzi ose akabatanidzwa pamwechete (Einav et al. 2015) . Izvi zvinongoratidzira zvinoratidza kuti pane zvimwe zvinhu zvakasiyana-zvakadai sezviyeuchidzo-mutengo unotanga une zvishoma zvingaita mukana wekutengesa ( \(x\) -axis) uye zvakanyanya kuitika pamutengo wokupedzisira wekutengesa ( \(y\) -axis). Yakashandiswa kubva kuna Einav et al. (2015) , chidzidzo 8.
Kunyange kana iwe usina kunyanya kufarira kuendesa kune e-eBay, unofanirwa kunakidza nzira iyo chiitiko 2.9 uye chikamu chechipiri 2.10 inopa kunzwisisa kwakapfuma kweBay pane kuongororwa kusinganzwisisi kunotsanangura ukama huri pakati uye kubatana nemhando dzakasiyana siyana dzezvinhu. Uyezve, kunyange zvazvo zvingave zvesayenzi kuti zvive nemafungiro aya asinganyatsozivikanwi neminda yekuongorora, mari yaizoita kuti zviitiko zvakadaro zvisingakwanisike.
Sezvo nekuedza kwepanyama, pane nzira dzakawanda dzinofanana dzinogona kutungamirira kuhuwandu hwakaipa. Ndinofunga kuti chinonyanya kukoshesa nekuenzanisa kuenzanisa ndechokuti vanogona kufarirwa nezvinhu zvisingashandisi muhutano. Semuenzaniso, mumigumisiro yavo mikuru, Einav nevamwe vaaishanda vakaita zvakafananidza pazvikamu zvina: nhamba yeDhizi yekutengesa, chikamu chezvinhu, chinyorwa chebhuku, uye subtitle. Kana zvinhu zvacho zvakasiyana nenzira dzisina kushandiswa pakufananidza, zvino izvi zvinogona kusimbisa kusaenzanisa. Somuenzaniso, kana "bhaggolfer" yakaderedza mitengo yeCharmmade Burner 09 Mutyairi munguva yechando (apo gorofu mapoka madzimai haasati azivikanwa), zvino zvinogona kuonekwa kuti kutsika kwekutanga kwekutengesa kunotungamirira kuzasi kwekutengesa, kana zvichange zviri nguva dzakasiyana-siyana mukudiwa. Imwe nzira yekugadzirisa nyaya iyi iri kuedza marudzi akawanda akasiyana. Semuenzaniso, Einav nevanoshanda navo vakadzokorora kuongororwa kwavo asi kusiyanisa nguva yewindo rinoshandiswa pakufananidza (kufanana zvakasarudzwa zvinosanganisira zvinhu zvakatengeswa mukati megore rimwe, mumwedzi umwe, uye nekufungisisa). Nenzira yakanaka, vakawana mhinduro yakafanana kune windows nguva dzose. Chimwe chinetseka nekuenzanisa kunobuda kubva kududziro. Inofanirwa kuenzanirana inoshandiswa chete kunowirirana nedheta; hazvirevi kumatambudziko asingagoni kuenzaniswa. Somuenzaniso, kuburikidza nekudzikisa kutsvakurudza kwavo kune zvinhu zvaive nezvinyorwa zvakawanda, Einav nevanoshanda navo vari kutarisa kune vatengesi vezvidzidzo uye vese. Nokudaro, patinenge tichidudzira zvienzanidzo izvi tinofanira kuyeuka kuti zvinongoshanda kune iyi subset yeBay.
Kufananidza inzira yakasimba yekuwana kufananidza kwakanaka mune zvisiri nyaya yekuedza. Kune vakawanda masayendisiti ezvesuzhinji, kufanana kunonzwa kachipiri-kwakanakisisa kuedza, asi iyo ndiyo kutenda kunogona kugadziridzwa, zvishoma. Kufananidza nehuwandu hwemashoko kunogona kunge kuri nani kudarika nhamba shomanana yemasaini ekuedza apo (1) heterogeneity mumigumisiro inokosha uye (2) zvinoshandiswa zvakakosha zvinoda kuenzaniswa zvakaenzana. Tafura 2.4 inopa mamwe mimwe mienzaniso yekufananidza kunogona kushandiswa nehukuru hwemashoko.
| Kutsvaga kwakanyanya | Big data source | Dheuteronomio |
|---|---|---|
| Migumisiro yokuputika pamhirizhonga yemapurisa | Stop-and-frisk rekodhi | Legewie (2016) |
| Migumisiro yaSeptember 11, 2001 pamusoro pemhuri nevavakidzani | Kuvhota zvinyorwa uye zvipo zvekupa | Hersh (2013) |
| Kusangana nemagariro evanhu | Kukurukurirana uye kugadzirwa kwezvinhu zvakagadzirwa | Aral, Muchnik, and Sundararajan (2009) |
Mukupedzisa, kuongororwa kwemigumisiro inokonzera kubva kune zvisiri nyaya yekuedza kwakaoma, asi nzira dzakadai sedzidzo dzepanyama uye kugadziriswa kwenhamba (semuenzaniso, kufanana) zvinogona kushandiswa. Mune mamwe mamiriro ezvinhu, nzira idzi dzinogona kuipa zvakanyanya, asi kana dzichinyatsocherechedzwa, nzira idzi dzinogona kubatsira dzinobatsira nzira yekuedza iyo ndinorondedzera muchitsauko 4. Uyezve, nzira idzi mbiri dzinoratidzika kuti dzinogona kubatsirwa nekukura kwegara nguva dzose- pane, guru dhidhiyo maitiro.
