Gilbert Chin Two of the methodologies used to compare the efficacies of treatments
are randomized placement of participants in experimental studies
and statistical or propensity matching of participants on confounding
variables in observational studies. Both approaches have their
proponents and might plausibly carry comparable weight in evidentiary
assessments. Bastardi
et al. developed a scenario in which a
matching study (in comparison to a randomized one) was described
as favoring home care of children to one group of participants,
whereas a second group of participants received the information
that the matching study favored day care. All of the participants
were soon to become parents, and their preexisting belief was
that home care was superior, although half of them were intending
to use day care. When confronted with these scenarios in a crossed
design, those who intended to use home care for their children
did not judge one methodology to be more reliable than the other
and maintained their stance about the superiority of home care.
On the other hand, the internally conflicted participants (that
is, those who intended to use day care) did regard the matching
protocol as better when it favored day care, and this sufficed
to shift their belief to the point where home care and day care
were viewed as equivalent.
Psychol. Sci. 22, 10.1077/0956797611406447 (2011).
