4.4.3 Sassan

Gwaje-gwajen gwada abin da ya faru. Sassan bayyana dalilin da ya sa da kuma yadda ya faru.

Na uku key ra'ayin domin motsi bayan sauki gwajen ne sunadaran. Sassan gaya mana dalilin da ya sa ko yadda wani magani ya sa wani sakamako. The tsari na neman sunadaran kuma wani lokacin ake kira neman tsoma bakin canji ko sasantawa canji. Ko da yake gwajen ne mai kyau ga kimantawa causal effects, suna sau da yawa ba tsara don bayyana sunadaran. Digital shekaru gwajen iya taimaka mana gane sunadaran a cikin hanyoyi biyu: 1) su taimaka mana mu tattara more tsari bayanai da kuma 2) suka taimaka mana mu jarraba yawa related jiyya.

Saboda sunadaran ne tricky domin ayyana ƙa'ida (Hedström and Ylikoski 2010) , zan fara da mai sauki misali: limes da scurvy (Gerber and Green 2012) . A cikin 18th karni likitoci da wani kyakkyawan mai kyau ma'ana cewa a lokacin da jirgin ya ci limes ba su samun scurvy. Scurvy ne mai mummunan cuta saboda haka wannan shi ne iko bayani. Amma, wadannan likitoci ba su sani ba me ya sa limes hana scurvy. Ba sai 1932, kusan shekaru 200 baya, cewa masana kimiyya zai iya dogara nuna cewa bitamin C shi ne dalilin da lemun tsami hana scurvy (Carpenter 1988, p 191) . A wannan yanayin, bitamin C ne inji ta hanyar abin da limes hana scurvy (Figure 4.9). Hakika, gano inji yana da muhimmanci sosai kimiyya-kuri'a na kimiyya da ake game da fahimtar dalilin da ya sa abubuwa. Gano hanyoyin da muhimmanci sosai kusan. Da zarar mun gane dalilin da ya sa a lura aiki, za mu iya yiwuwar inganta sabon jiyya cewa aiki ko da mafi alhẽri.

Adadi 4.9: Limes hana scurvy da inji shi ne Vitamin C.

Abin baƙin ciki, isolating sunadaran da matukar wuya. Ba kamar limes da scurvy, a da yawa zamantakewa saituna, jiyya yiwuwa aiki ta hanyoyi da yawa m tafarkin, abin da ya sa kadaici da sunadaran da wuya matuƙa. Duk da haka, a cikin akwati na zamantakewa norms da makamashi amfani, masu bincike sun yi kokarin ware sunadaran da tattara tsari bayanai da kuma gwada shafi jiyya.

Daya hanyar jarraba yiwu sunadaran ne da tattara tsari bayanai game da yadda magani tasiri yiwu sunadaran. Alal misali, tuna cewa Allcott (2011) ya nuna cewa Home Energy Rahotanni sa mutane su runtse daga wutar lantarki mai cutarwa. Amma, ta yaya wadannan rahotanni ƙananan wutar lantarki mai cutarwa? Mene ne sunadaran? A cikin wata follow-up binciken, Allcott and Rogers (2014) ha] a hannu da ikon kamfanin cewa, ta hanyar rago shirin, ya samu bayani a kan abin da masu amfani da kyautata su kayan more makamashi m model. Allcott and Rogers (2014) gano cewa dan kadan more mutane karbar Home Energy Rahotanni kyautata m kayan. Amma, wannan bambanci saboda haka kananan cewa shi ne kawai zai iya asusu na 2% na karu a makamashi amfani a cikin bi da gidaje. A wasu kalmomin, nema kyautayuwa kasance ba da rinjaye inji ta da Home Energy Report rage wutar lantarki amfani.

A karo na biyu hanyar nazarin sunadaran ne gudu gwaje-gwajen da dan kadan daban-daban versions na magani. Alal misali, a cikin gwaji na Schultz et al. (2007) da dukan m Home Energy Report gwaje-gwajen, mahalarta sun bayar da wani magani da cewa yana da biyu main sassa 1) tips game makamashi ajiyar banki da kuma 2) bayanai game da makamashi amfani dangi da takwarorinsu (Figure 4.6). Saboda haka, yana yiwuwa cewa makamashi ceto tips ne abin da ya sa canji, ba tsara bayanai. Don tantance yiwuwar cewa tips kadai zai kasance isa, Ferraro, Miranda, and Price (2011) ha] a hannu da ruwa kamfanin kusa Atlanta, GA, da gudu a related gwaji a kan ruwa kiyayewa shafe game 100,000 gidaje. Akwai hudu yanayi:

• wata ƙungiya cewa karbi tips on ceton ruwa.
• wata ƙungiya cewa karbi tips on ceton ruwa + a halin kirki roko domin ya ceci ruwa.
• wata ƙungiya cewa karbi tips on ceton ruwa + a halin kirki roko domin ya ceci ruwa + bayanai game da ruwa amfani dangi da takwarorinsu.
• a kula da kungiyar.

The masu bincike gano cewa tips kawai magani da wani sakamako a kan ruwa mai cutarwa a takaice (daya shekara), matsakaici (biyu shekara), da kuma dogon (shekaru uku) kalma. The tips + roko magani ya sa mahalarta su rage ruwa mai cutarwa, amma kawai a cikin gajere. A karshe, cikin tips + roko + tsara bayanai magani sa rage amfani a takaice, matsakaici, da kuma dogon lokaci (Figure 4.10). Wadannan irin gwaje-gwajen da unbundled jiyya ne mai kyau hanyar Figure fitar da wani ɓangare na lura-ko wane sassa game-ne waɗanda suke haifar da sakamako (Gerber and Green 2012, Sec. 10.6) . Alal misali, gwaji na Ferraro da kuma abokan aiki ya nuna mana cewa ruwa saving tips kaɗai ne bai isa ya rage ruwa mai cutarwa.

Figure 4.10: Results daga Ferraro, Miranda, and Price (2011) . Jiyya da aka aiko May 21, 2007, da kuma effects aka auna a lokacin bazaar na 2007, 2008, da kuma 2009. By unbundling lura da masu bincike fatan samar da mafi alhẽri ji na sunadaran. The tips kawai magani da gaske babu sakamako a takaice (daya shekara), matsakaici (shekaru biyu), da kuma dogon (shekaru uku) kalma. The tips + roko magani ya sa mahalarta su rage ruwa mai cutarwa, amma kawai a cikin gajere. The shawara + roko + tsara bayanai magani ya sa mahalarta su rage ruwa mai cutarwa a takaice, matsakaici, da kuma dogon lokaci. Tsaye sanduna suna kiyasta amincewa jinkiri. Dubi Bernedo, Ferraro, and Price (2014) ga ainihin binciken kayan.

Fi dacewa, wanda zai motsa hayin layering aka gyara (tips, tips + roko. Tips + roko + tsara bayanai) zuwa cikakken factorial zane-ma wani lokaci da ake kira \ (2 ^ k \) factorial zane-inda kowane yiwu hade da uku abubuwa ne gwada (Table 4.1). By gwada kowane yiwu hade da aka gyara, da masu bincike za su iya cika tantance sakamako kowane bangaren a warewa da kuma a hade. Alal misali, gwaji na Ferraro da kuma abokan aiki ba bayyana ko tsara kwatanta shi kadai zai yi isa ya haifar da dogon lokaci canje-canje a hali. A baya, wadannan full factorial kayayyaki sun yi wuya a gudanar da su, domin ya bukatar wani babban yawan mahalarta da kuma su na bukatar bincike don su iya daidai iko da kuma isar da wani babban yawan jiyya. Amma, da digital shekaru kawar da wadannan tafarkin constraints a wasu yanayi.

A takaice, sunadaran-da tafarkin ta hanyar abin da wani magani yana da wani sakamako-ne wuce yarda da muhimmanci. Digital shekaru gwaje-gwajen da masu bincike za su iya taimaka koyi game da sunadaran by 1) tattara bayanai da kuma tsari 2) kunna full factorial kayayyaki. The sunadaran shawara da wadannan hanyoyin iya sa'an nan da gwada kai tsaye daga gwaje-gwajen da musamman tsara don gwada sunadaran (Ludwig, Kling, and Mullainathan 2011; Imai, Tingley, and Yamamoto 2013; Pirlott and MacKinnon 2016) .

A cikin duka, waɗannan uku Concepts-tushe. heterogeneity magani effects. kuma sunadaran-samar da wani iko kafa ra'ayoyi domin zayyana da fassara gwaje-gwajen. Wadannan Concepts taimako bincike motsa bayan sauki gwajen game da abin da "ayyuka" to aukaka gwaje-gwajen da cewa suna da tighter links to ka'idar, cewa bayyana inda kuma me ya sa jiyya aiki, kuma zai ma taimaka masu bincike tsara more m jiyya. Aka ba da wannan na ra'ayi baya game gwaje-gwajen, zan yanzu juya zuwa yadda za ka iya zahiri sa ka gwajen faru.