1010 Journal of Economic Literature,Vol.XLII (December 2004 terminology in instructions.3 We argue that Our second point is that many of the char there is something methodologically funda- acteristics of field experiments can be found mental behind this trend.Field experiments in varying,correlated degrees in lab experi differ from laboratory experiments in ma ments.Thus,many of the characteristics that imply mpting to view field people identify with field experiments are not only found in field experiments,and nts.w argu should not be used to differentiate them e them from lab experiments. "in lab tory exper Our third point,following from the first two is that th ere is much to learn from field t be precisely the oppo if it is arti icial to the subject or context of the returning to the lab.The task.In the en we se e field experiments as methodologically comple entary to rol in the field are traditional laboratory experiments. f the Our primary point is that dissecting the en e lab.T characteristics of field experiments help field experimen s can nelp one c gn bett define what might be better called an ideal and have a methodological exneriment in the sense that one is able to role quite apart from their complementarity observe a subject in a controlled setting but at a substantive level where the subiect does not n ceive In section 2 we offer a typology of field the ontrols as being un dth is n experiments in the literature,identifying the de otion bei key characteristics defining the species.We idea tha At first blush sub ects in setting et have eriments or more se contr ctory,t ague thgh accurately to identify different characteris. We explain this jargon n from experimental economic a bright line to define ne field and other Murphy (1973 set of hat expe egrees in a field sub ents in a e propos d to de ermine the ield context of an h the cl brea experiment:t nature of thes ect poo the nature of the information that the sub group a fr jects bring to the task,the nature of the com modity,the nature of the task or trading rules applied,the nature of the stakes,and the environment in which the subjects operate. ud not seem unnatural to th Having identified what defines a field exper oing what come iment.in section 3 we put experiments in Along s omists can identify see Ed es to in ch a the ing-Re (1) d auctions in tute field ments.I through an of rev and we four mor single-unit auction format the des broad types of field eaknesse