Assess downstream impact of classified changes — assess

Combines a classified change set with a lineage graph to identify which downstream variables, analyses and outputs could be affected. Impact is graded as "definitely_affected", "potentially_affected" or "unlikely", with an explicit rationale and the triggering change identifiers.

Usage

assess_impact(changes, lineage, policy = impact_policy(), ...)

Arguments

changes: A classified tdiff object (output of classify_changes()) or a change register with a category column.
lineage: A td_lineage object from define_lineage().
policy: An impact_policy() object.
...: Reserved for future extensions.

Value

An object of class td_impact with elements impacts, by_subject, unlinked, summary, policy and meta.

Details

trialdiff never claims statistical impact. Every affected analysis or output is reported as requiring programmer/statistician review and, where appropriate, a rerun.

Examples

old <- data.frame(USUBJID = c("S1", "S2"), TRT01P = c("Placebo", "Drug A"))
new <- data.frame(USUBJID = c("S1", "S2"), TRT01P = c("Drug A", "Drug A"))
diff <- compare_cut(old, new, by = "USUBJID", dataset = "ADSL") |>
  classify_changes()
lineage <- define_lineage(
  lineage_edge("ADSL.TRT01P", "ADLB.TRT01P", relationship = "groups_by"),
  lineage_edge("ADLB.TRT01P", "MMRM", relationship = "models"),
  lineage_edge("MMRM", "Table_14_2_1", relationship = "reports")
)
assess_impact(diff, lineage)
#> 
#> ── trialdiff impact assessment ─────────────────────────────────────────────────
#> Dataset(s): "ADSL"
#> Changes assessed: 1
#> 
#> ── Impact summary ──
#> 
#> # A tibble: 5 × 2
#>   metric                              value
#>   <chr>                               <int>
#> 1 nodes_definitely_affected               1
#> 2 nodes_potentially_affected              2
#> 3 nodes_unlikely                          0
#> 4 analyses_or_outputs_requiring_rerun     2
#> 5 unlinked_changes                        1
#> ── Affected downstream objects ──
#> 
#> # A tibble: 3 × 4
#>   node         node_type level                depth
#>   <chr>        <chr>     <chr>                <int>
#> 1 ADLB.TRT01P  variable  definitely_affected      1
#> 2 MMRM         analysis  potentially_affected     2
#> 3 Table_14_2_1 output    potentially_affected     3
#> ! 1 changed node has no declared lineage.
#> ℹ Impact is a review signal only; statistical impact requires rerunning analyses.