Dear all,
I am struggling about the implications of combining two meta-analyses (the
potential shortcomings of conducting a second-order meta-analysis):
Meta-analysis1 was achieved with the ln(RR1)[based on variable x1]
Meta-analysis2 was achieved with the ln(RR2) [based on variable X2]
There is an underlying relation between the units of X1 (u1) and X2 (u2):
u3=u1*3k ; u3=u2*300k
I wonder if it is possible to perform such analysis just including for
instance as a moderator the categorical variable for units (units1,units2)?
Am I missing something in the implications of the units that would affect
the correct comparison of ln(RR1) and ln (RR2)? I have consulted the work
of Schmidt and Oh (2013), Castellanos and Verd? (2012), Tamin (2011), and
other articles related to effects sizes calculations but I am not pretty
sure if I am not considering some kind of previous correction of the effect
sizes of the first order meta-analyses (or if it is not possible at all).
Maybe you can point me out in some direction about it.
Thank you in advance,
Diego
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