Resolve the survey's paths, flow and display logic

Combines resolve_flow() (block-level routing) with a within-block display-logic reachability analysis. For each flow path it partitions the questions into those always shown, those that may be shown (a display-logic condition we cannot evaluate before fieldwork), and those whose display logic is shown to be false on that path because of the questions the path does not show (see classify_reachability() for the rule).

Usage

resolve_paths(qsf, max_paths = 10000L, catalogue = NULL, blocks = NULL)

Arguments

qsf

A qsf_raw object from read_qsf().

max_paths

Passed to resolve_flow().

catalogue, blocks

Optional precomputed parse_qsf() and resolve_live_blocks() results for this qsf. Internal: lets burden_report() parse and resolve the survey once and reuse it. When NULL (default) they are computed here, so the public behaviour is unchanged.

Value

A tibble, one row per flow path, with the resolve_flow() columns plus:

q_always

List column: question ids shown on every visit to this path.

q_maybe

List column: question ids gated by an unresolved condition.

n_gates

Distinct root trigger questions active on this path.

Details

Interior enumeration of the display-logic state space is not performed: a large survey can carry dozens of root display-logic gates with choice-level mutual exclusivity, which needs a constraint solver. The honest output is the structural band per path (floor = always, ceiling = always + maybe); see path_burden().

Examples

qsf_path <- system.file("extdata", "demo_travel_survey.qsf",
                         package = "surveyBurden")
paths <- resolve_paths(read_qsf(qsf_path))
paths[, c("path_id", "terminates_early", "n_gates")]
#> # A tibble: 4 × 3
#>   path_id terminates_early n_gates
#>     <int> <lgl>              <int>
#> 1       1 TRUE                   0
#> 2       2 TRUE                   0
#> 3       3 FALSE                  4
#> 4       4 FALSE                  3