Selecting the adjustment set and estimating on the same rows makes the target parameter itself a function of the data, and the usual influence-curve SE then prices the estimator but not the selection. The data-adaptive target-parameter framework fixes it by splitting: the subset is chosen on the ODD indices, the parameter is defined and estimated on the EVEN indices, and given the split the target is a fixed (if random) parameter whose influence curve needs no selection correction.
Details
Selection ranks covariates by the absolute correlation with the
treatment-residualised outcome on the selection half and keeps the top
ceiling(p/2). The reported se is a HALF-sample standard
error; it does not shrink by using the selection rows, and that is the
price of an honest interval.
References
Hubbard, A. E., Kherad-Pajouh, S. & van der Laan, M. J. (2016). International Journal of Biostatistics 12(1):3-19.
Examples
Tmlsbs(y = c(1, 2, 3, 4, 5, 6, 7, 8), D = c(1, 2, 3, 4, 5, 6, 7, 8), X = c(1, 2, 3, 4, 5, 6, 7, 8))
#> $estimate
#> [1] 6.755609e+15
#>
#> $se
#> [1] 2.161287e+15
#>
#> $eps
#> [1] 8.211339e+13
#>
#> $selected
#> [1] 1
#>
#> $n_selected
#> [1] 1
#>
#> $n_est
#> [1] 4
#>
#> $n
#> [1] 8
#>
#> $method
#> [1] "Sample-split TMLE on a data-adaptively selected covariate subset"
#>
#> attr(,"class")
#> [1] "morie_rich_result" "list"
