@article {6100,
	title = {The Perry Preschoolers at late midlife: A study in design-specific inference},
	year = {2019},
	publisher = {National Bureau of Economic Research},
	address = {Cambridge, MA},
	abstract = {This paper presents the first analysis of the life course outcomes through late midlife (around age 
55)
for  the  participants  of  the  iconic  Perry  Preschool  Project,  an  experimental  high-quality 
preschool  program
for  disadvantaged  African-American  children  in  the  1960s.  We  discuss  the 
design of the experiment,
compromises in and adjustments to the randomization protocol, and the 
extent of knowledge about
departures from the initial random assignment. We account for these 
factors in developing conservative
small-sample hypothesis tests that use approximate worst-case 
(least  favorable)  randomization  null
distributions.  We  examine  how  our  new  methods  compare 
with  standard  inferential  methods,  which
ignore  essential  features  of  the  experimental  setup. 
Widely  used  procedures  produce  misleading  inferences
about  treatment  effects.  Our  design-
specific  inferential  approach  can  be  applied  to  analyze  a  variety
of  compromised  social  and 
economic experiments, including those using re-randomization designs.
Despite the conservative 
nature of our statistical tests, we find long-term treatment effects on crime,
employment, health, 
cognitive  and  non-cognitive  skills,  and  other  outcomes  of  the  Perry  participants.
Treatment 
effects  are  especially  strong  for  males.  Improvements  in  childhood  home  environments
and 
parental attachment appear to be an important source of the long-term benefits of the program.},
	keywords = {preschool, The Perry Preschool Project},
	url = {https://www.nber.org/papers/w25888.pdf},
	author = {Heckman, J. J. and Karapakula, G.}
}
