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EC-IPW method constructor

Source: R/ec_ipw.R
ec_ipw.Rd

Creates a method object for IPW estimation with external control borrowing (Zhou et al., 2024). Pass to setup_analysis_primary and run_analysis.

Usage

ec_ipw(ps_formula, weight = NULL, bootstrap = NULL, bootstrap_ci_type = NULL)

Arguments

ps_formula

Formula string for the propensity score model predicting trial participation. The left-hand side is replaced internally (e.g., "S ~ x1 + x2 + x3").

weight

Borrowing weight. NULL (default) for data-adaptive optimal weight, 0 for RCT-only, or a value in (0, 1].

bootstrap

Number of bootstrap replicates, or NULL (default) for sandwich variance with normal CIs.

bootstrap_ci_type

Bootstrap CI type, or NULL (default) which resolves to "perc" when bootstrap is set. One of "perc", "bca", "norm", "basic", or "stud".

Value

An S4 object of class ec_ipw_method.

References

Zhou et al. (2024). Causal estimators for incorporating external controls in randomized trials with longitudinal outcomes. JRSS-A. doi:10.1093/jrsssa/qnae075

Examples

# optimal weight, sandwich SE
ec_ipw(ps_formula = "S ~ x1 + x2 + x3 + x4 + x5")
#> An object of class "ec_ipw_method"
#> Slot "ps_formula":
#> [1] "S ~ x1 + x2 + x3 + x4 + x5"
#> 
#> Slot "weight":
#> NULL
#> 
#> Slot "bootstrap":
#> NULL
#> 
#> Slot "bootstrap_ci_type":
#> NULL
#> 
#> Slot "optimal_weight_flag":
#> [1] FALSE
#> 
#> Slot "wt":
#> [1] 0
#> 
#> Slot "model_form_piS":
#> [1] ""
#> 
#> Slot "model_form_piA":
#> [1] ""
#> 
#> Slot "model_form_mu0_ext":
#> [1] ""
#> 
#> Slot "model_form_mu0_rct":
#> [1] ""
#> 
#> Slot "model_form_mu1_rct":
#> [1] ""
#> 
#> Slot "method_name":
#> [1] "EC-IPW"
#> 
#> Slot "bootstrap_flag":
#> [1] FALSE
#> 
#> Slot "bootstrap_obj":
#> <bootstrap_obj>
#>   Replicates: 500 
#>   CI type: Percentile 
#> 

# no borrowing
ec_ipw(ps_formula = "S ~ x1 + x2 + x3 + x4 + x5", weight = 0)
#> An object of class "ec_ipw_method"
#> Slot "ps_formula":
#> [1] "S ~ x1 + x2 + x3 + x4 + x5"
#> 
#> Slot "weight":
#> [1] 0
#> 
#> Slot "bootstrap":
#> NULL
#> 
#> Slot "bootstrap_ci_type":
#> NULL
#> 
#> Slot "optimal_weight_flag":
#> [1] FALSE
#> 
#> Slot "wt":
#> [1] 0
#> 
#> Slot "model_form_piS":
#> [1] ""
#> 
#> Slot "model_form_piA":
#> [1] ""
#> 
#> Slot "model_form_mu0_ext":
#> [1] ""
#> 
#> Slot "model_form_mu0_rct":
#> [1] ""
#> 
#> Slot "model_form_mu1_rct":
#> [1] ""
#> 
#> Slot "method_name":
#> [1] "EC-IPW"
#> 
#> Slot "bootstrap_flag":
#> [1] FALSE
#> 
#> Slot "bootstrap_obj":
#> <bootstrap_obj>
#>   Replicates: 500 
#>   CI type: Percentile 
#> 

# optimal weight with bootstrap
ec_ipw(
  ps_formula = "S ~ x1 + x2 + x3 + x4 + x5",
  bootstrap = 500
)
#> An object of class "ec_ipw_method"
#> Slot "ps_formula":
#> [1] "S ~ x1 + x2 + x3 + x4 + x5"
#> 
#> Slot "weight":
#> NULL
#> 
#> Slot "bootstrap":
#> [1] 500
#> 
#> Slot "bootstrap_ci_type":
#> [1] "perc"
#> 
#> Slot "optimal_weight_flag":
#> [1] FALSE
#> 
#> Slot "wt":
#> [1] 0
#> 
#> Slot "model_form_piS":
#> [1] ""
#> 
#> Slot "model_form_piA":
#> [1] ""
#> 
#> Slot "model_form_mu0_ext":
#> [1] ""
#> 
#> Slot "model_form_mu0_rct":
#> [1] ""
#> 
#> Slot "model_form_mu1_rct":
#> [1] ""
#> 
#> Slot "method_name":
#> [1] "EC-IPW"
#> 
#> Slot "bootstrap_flag":
#> [1] TRUE
#> 
#> Slot "bootstrap_obj":
#> <bootstrap_obj>
#>   Replicates: 500 
#>   CI type: Percentile 
#> 

# fixed weight with bootstrap
ec_ipw(
  ps_formula = "S ~ x1 + x2 + x3 + x4 + x5",
  weight = 0.3,
  bootstrap = 500
)
#> An object of class "ec_ipw_method"
#> Slot "ps_formula":
#> [1] "S ~ x1 + x2 + x3 + x4 + x5"
#> 
#> Slot "weight":
#> [1] 0.3
#> 
#> Slot "bootstrap":
#> [1] 500
#> 
#> Slot "bootstrap_ci_type":
#> [1] "perc"
#> 
#> Slot "optimal_weight_flag":
#> [1] FALSE
#> 
#> Slot "wt":
#> [1] 0
#> 
#> Slot "model_form_piS":
#> [1] ""
#> 
#> Slot "model_form_piA":
#> [1] ""
#> 
#> Slot "model_form_mu0_ext":
#> [1] ""
#> 
#> Slot "model_form_mu0_rct":
#> [1] ""
#> 
#> Slot "model_form_mu1_rct":
#> [1] ""
#> 
#> Slot "method_name":
#> [1] "EC-IPW"
#> 
#> Slot "bootstrap_flag":
#> [1] TRUE
#> 
#> Slot "bootstrap_obj":
#> <bootstrap_obj>
#>   Replicates: 500 
#>   CI type: Percentile 
#>