Formula: DEFF = Var_complex / Var_SRS
Details
Decomposed the way Kish does it, into the unequal-weighting effect DEFF_w = n sum w_i^2 / (sum w_i)^2 and the clustering effect DEFF_c = 1 + (m0 - 1) rho, where rho is the one-way ANOVA intraclass correlation and m0 the Kish average cluster size. The reported DEFF is their product. Equal weights give DEFF_w = 1 exactly, and singleton clusters give DEFF_c = 1 exactly.
Examples
V <- c(1, 2, 3, 4, 5, 6, 7, 8)
Desigeff(V)
#> $estimate
#> [1] 1
#>
#> $deff_w
#> [1] 1
#>
#> $deff_c
#> [1] 1
#>
#> $rho
#> [1] 0
#>
#> $m0
#> [1] 1
#>
#> $n_eff
#> [1] 8
#>
#> $n
#> [1] 8
#>
#> $method
#> [1] "Kish design effect: unequal weighting x clustering"
#>
#> attr(,"class")
#> [1] "morie_rich_result" "list"
