Stata and R code for computing design effects when only survey weights and average DEFFs are available, following West and McCabe (2012).
The original Stata code is by West and McCabe; the R implementation is a direct translation by Sinozich.
You can verify the results from deft2corr() against Table 1 in West and McCabe (2012). Note that exponentiated values may differ slightly due to varied handling of floating point numbers across software packages.
# Proportion: Nasal administration
deft2corr(0.3627,0.0257,2,1.3528,0)
# AOR: NMPM vs. MPNM
deft2corr(1.7938,0.5310,2,1.4987,1)
# AOR: NMO vs. MPNM
deft2corr(2.0390,0.5172,2,1.5098,1)