WFC

WFC is an R package for reviewable survey weighting. Version 2.0 makes one rule non-optional: weights may be built only from declared design variables and an independently sourced, verified target. Study outcomes enter only after the weights are locked.

This design serves two kinds of users:

• survey researchers get a guided sequence with plain-language stops and next actions; and
• statistical teams and AI agents get stable objects, identities, condition codes, and complete audit fields.

The same result can be shown as a short decision view or a detailed statistical view. The two views come from one object and must agree.

What WFC 2.0 prevents

Public weighting functions reject raw data frames, ordinary target objects, demo targets, changed identities, self-approval by an agent, and runtime changes to ID or base-weight roles. Manual targets, target shrinkage, inline target moments, manual pipeline modes, and runtime margin injection are not supported.

These controls reduce accidental and ordinary misuse. They cannot prove that a source document is truthful or stop a determined person from editing open source code. Accountable human review remains necessary.

Installation

Install the development version from GitHub:

remotes::install_github("weiandata/WFC")

Files used by the safe workflow

A production run normally starts with four files:

1. a design-only survey table containing IDs, calibration fields, and declared sampling-design fields;
2. a separate analysis table containing study outcomes;
3. a CSV or Excel target table from an external authority; and
4. a companion .source.dcf evidence record for that target table.

Use wf_target_template() if the target-table layout is unfamiliar:

library(WFC)

dims <- wf_dims(
  age_group = c("18-34", "35-54", "55+"),
  region = c("north", "south")
)

wf_target_template(
  "population-margins-template.csv",
  dims = dims
)

The template creates the data file and its companion DCF form. Complete the source fields, update the checksum after the data file is final, and obtain the file before inspecting study outcomes.

WFC also installs synthetic format examples named safe-target-example.csv, safe-target-example.xlsx, and their separate .source.dcf files. They are marked demo-only and cannot enter production planning.

Complete controlled workflow

1. Prepare outcome-free design data

library(WFC)

dims <- wf_dims(
  age_group = c("18-34", "35-54", "55+"),
  region = c("north", "south")
)

design_only <- read.csv("survey-design.csv")
analysis_data <- read.csv("survey-outcomes.csv")

design <- wf_prepare_design(
  design_only,
  id = "person_id",
  calibration = c("age_group", "region"),
  base_weight = "base_weight"
)

Every column in design_only must have a declared design role. Keep outcomes such as satisfaction, vote choice, approval, score, or pass/fail in analysis_data.

2. Import an external target and its evidence

Population-count target:

target <- wf_import_target(
  data_file = "population-margins.csv",
  source_file = "population-margins.csv.source.dcf",
  dims = dims,
  key_map = c(age_group = "age_group", region = "region"),
  count = "population_count",
  production = TRUE
)

Independent reference-sample target:

reference_target <- wf_import_reference(
  data_file = "reference-sample.csv",
  source_file = "reference-sample.csv.source.dcf",
  dims = dims,
  feature = "reference_weight",
  production = TRUE
)

Import verifies source completeness, declared selection timing, demo status, and the SHA-256 checksum. It does not decide whether the source is scientifically appropriate; that remains part of human review.

3. Plan without seeing outcomes

cell_plan <- wf_plan_cells(
  design,
  target,
  dims,
  min_cell = 5,
  max_weight_ratio = 4
)

plan <- wf_plan_weights(
  design,
  target,
  dims,
  method = "raking",
  bounds = c(0.3, 3),
  min_cell = 5,
  cell_plan = cell_plan
)

plan$ready
plan$issues
is.null(plan$weights)

Planning does not calculate weights. It records the exact inputs, checks, method, limits, and any deterministic category merge for review.

4. Obtain separate human approval

approval <- wf_approve_plan(
  plan,
  approver = "Qualified reviewer full name",
  role = "Statistician",
  note = "Reviewed source, support, method, limits, and intended use"
)

An AI agent may prepare the plan but may not create this attestation for itself. The name and role must identify the actual human reviewer.

5. Execute the unchanged plan once

locked <- wf_execute_plan(
  plan,
  approval,
  design,
  target
)

Changing the design, target, plan, or approval breaks the identity chain and stops execution.

6. Attach outcomes after weight locking

analysis_ready <- wf_attach_weights(
  analysis_data,
  locked,
  id = "person_id",
  weight_name = ".weight"
)

impact <- wf_assess_impact(
  locked,
  analysis_data,
  id = "person_id",
  outcomes = c("satisfaction", "approved")
)

Impact assessment describes what the already locked weights change. It cannot re-plan, reapprove, or overwrite the weights.

7. Produce views for different readers

decision_view <- wf_report(
  locked,
  audience = "decision"
)

statistical_view <- wf_report(
  locked,
  audience = "statistician"
)

impact_detail <- wf_report(
  impact,
  audience = "statistician"
)

wf_audit_export(locked, "weighting-audit.json")

The decision view emphasizes status, main risks, and next actions. The statistical view exposes full tables, convergence information, identities, and provenance for further analysis.

Direct functions for statistical users

Advanced users may call wf_calibrate(), wf_rake(), wf_poststrat(), wf_auto_trim(), or wf_autoweigh() directly, but their first inputs must still be the unchanged design and target objects:

raked <- wf_rake(design, target, tol = 1e-8)

bounded <- wf_calibrate(
  design,
  target,
  method = "logit",
  bounds = c(0.3, 3)
)

trim_review <- wf_auto_trim(
  design,
  target,
  caps = c(2, 4, 6, 8)
)

ID and base-weight columns come from wf_prepare_design() and cannot be overridden at this stage.

AI agent integration

An agent should preserve whole WFC objects and their identities. A minimal handoff object can be prepared like this:

handoff <- list(
  plan = plan,
  plan_identity = plan$identity,
  design_identity = design$identity,
  target_identity = target$identity,
  required_human_action = "Review and approve the unchanged plan"
)

If an agent attempts approval, WFC returns wf_error_safety. Agents should read the stable payload and stop:

refusal <- tryCatch(
  wf_approve_plan(
    plan,
    approver = "Automated agent",
    role = "assistant",
    actor_type = "agent"
  ),
  wf_error_safety = function(condition) condition$data
)

refusal[c("code", "severity", "field", "next_actions")]

Do not edit identities, manufacture a human name, widen limits, switch targets, or retry after viewing outcomes.

Migration from WFC 1.x

See Migrating from WFC 1.x to WFC 2.0. Behavior that selected desired results has no compatibility switch and no supported replacement.

License

WFC is licensed under GPL (>= 2). Copyright and contributor information are in inst/COPYRIGHTS and DESCRIPTION.