2.4.3 Approximating gwajen

Muna iya m gwaje-gwajen da cewa ba za mu iya yi. Biyu, na fuskantar da musamman amfana daga digital shekaru suna matching da na halitta gwaje-gwajen.

Mutane da yawa da muhimmanci kimiyya da siyasa tambayoyi ne causal. Bari mu duba, misali, da wadannan tambaya: abin da ke cikin sakamako na aiki da horo shirin a kan Hakkin? Daya hanyar amsa wannan tambaya zai zama tare da yi da ka sarrafawa gwaji inda ma'aikata da aka da ka sanya wa ko dai sama horo ko ba sama horo. Sa'an nan kuma, masu bincike zai iya kimanta sakamakon horo ga wadannan mahalarta da kawai gwada sakamakon mutanen da suka karbi horo ga waɗanda cewa bai sami shi.

The m kwatanta shi ne m saboda wani abu da ya faru a gaban data aka ma tattara: da randomization. Ba tare da randomization, matsalar da yawa trickier. A bincike zai iya kwatanta Hakkin mutanen da suka aikin sanya hannu up for horo ga waɗanda suka ba su shiga-up. Wannan gwadawa zai yiwuwa ya nuna cewa mutanen da suka karbi horo sanã'anta more, amma nawa wannan ne saboda horo da kuma yadda wannan shi ne domin mutanen da hannu-up for horo ne daban-daban daga wadanda da ba su sa hannu-up for horo? A takaice, shi ne shi gaskiya kwatanta sakamakon wadannan kungiyoyin biyu na mutane?

Wannan damuwa game da m kwatancen kaiwa wasu masu bincike yi imani da cewa ba shi yiwuwa a yi causal kimomi ba tare da guje wani gwaji. Wannan da'awar ke da nisan. Duk da yake shi ne gaskiya cewa gwaje-gwajen da samar da karfi shaida ga causal effects, akwai wasu dabarun da za su iya samar da muhimmanci causal kimomi. Maimakon tunanin cewa causal kimomi ne ko dai m (a cikin akwati na gwaje-gwajen) ko ba zai yiwu ba (a cikin akwati na passively lura data), shi ne mafi alhẽri a yi tunani na dabarun domin yin causal kimomi kwance tare a maras iyaka daga karfi zuwa mafi raunin (Figure 2.4). A karfi karshen maras iyaka da ake yi da ka sarrafawa gwaje-gwajen. Amma, wadannan su ne sau da yawa wuya a yi a social bincike domin da yawa jiyya na bukatar unrealistic yawa na hadin gwiwa daga gwamnatoci ko kamfanoni. quite kawai akwai mutane da yawa gwaje-gwajen da cewa ba za mu iya yi. Zan sadaukar da dukan Chapter 4 to biyu da karfi da kuma kasawan na yi da ka sarrafawa gwaje-gwajen, kuma zan yi jayayya cewa a wasu lokuta, akwai karfi da da'a dalilai su yi gudu observational to gwaji hanyoyin.

Figure 2.4: maras iyaka da bincike dabarun kiyasta causal effects.

Motsi tare da maras iyaka, akwai yanayi inda masu bincike ba su baro-baro yi da ka. Wannan ne, masu bincike suna yunkurin koyi gwaji-kamar ilmi, ba tare da a zahiri yin wani gwaji. da sauƙi, wannan da yake faruwa a tricky, amma babban data ƙwarai inganta mu ikon yi causal kimomi a cikin wadannan yanayi.

Wani lokaci akwai saituna inda randomness a duniya ya faru ya halicci wani abu kamar wani gwaji ga masu bincike. Wadannan kayayyaki da ake kira halitta gwaje-gwajen, kuma za su yi la'akari, daki-daki a Sashe 2.4.3.1. Biyu fasali na babban data kafofin-m ko da yaushe-on yanayi da size-ƙwarai kara habaka mu ikon koya daga halitta gwaje-gwajen a lõkacin da suka auku.

Motsi kara daga yi da ka sarrafawa gwaje-gwajen, wani lokacin babu ko da wani taron a cikin yanayi, za mu iya amfani da su domin m wata halitta gwaji. A cikin wadannan saituna, za mu iya a hankali yi kwatancen cikin wadanda ba gwaji bayanai a wani ƙoƙari na kimanin wani gwaji. Wadannan kayayyaki da ake kira matching, kuma za su yi la'akari, daki-daki a Sashe 2.4.3.2. Kamar halitta gwaje-gwajen, matching ne mai zane da kuma amfana daga babban data kafofin. Musamman, da m size-biyu cikin sharuddan yawan lokuta kuma irin bayanai da yanayin-ƙwarai facilitates matching. Makullin bambanci tsakanin halitta gwaje-gwajen da matching shi ne cewa a cikin halitta gwaje-gwajen da bincike ya san tsari ta hanyar da magani aka sanya da kuma ya yi ĩmãni da shi ya zama bazuwar.

A ra'ayi na gaskiya kwatancen wanda ya motsa sha'awa da ya yi gwaje-gwajen kuma underlies biyu madadin hanyoyin: halitta gwaje-gwajen da matching. Wadannan hanyoyin zai taimaka maka ka kimanta causal effects daga passively lura data by ganowa gaskiya kwatancen zaune ciki na bayanai da ka riga da.