Name-Blind Variable-Role Detection by Data Signature

Deterministic, name-blind detection of variable roles (group, outcome, survival or duration time and event, coupled binary-continuous pairs, calendar time index, paired and agreement measurements, repeated measures and panels, scale and rating items, subject or entity identifier, covariate) in tabular data from any domain -- clinical, financial, social, experimental. Roles are assigned from each column's information-theoretic signature -- Shannon entropy, normalized mutual information, and distributional shape -- rather than from column names, so renaming columns to 'col_1', 'col_2', ... does not change the result ("Data inspice, non nomen"). An optional, capped name-based hint and automatic header-row detection are also provided. No large language models and no external data transmission. Extracted from the 'MDStatR' biostatistics engine; see Boynukara (2026) .

rolescry

Name-blind variable-role detection by data signature. Data inspice, non nomen -- inspect the data, not the name.

rolescry assigns statistical roles to the columns of a tabular dataset from any domain -- a clinical trial, a loan book, a firm-month panel, a survey -- group variable, continuous/binary outcome, survival time and event, paired and agreement measurement pairs, repeated measures, scale items, subject identifier, and covariates -- using only each column's information-theoretic signature (Shannon entropy, normalized mutual information, distributional shape and inter-column structure), never the column names. Renaming every column to col_1, col_2, ... does not change the result. No large language models, no external data transmission; detection is deterministic.

Detection is backed by two structural invariance guarantees -- renaming (RELABEL) and reordering (S_n) columns never change a result -- and a single pre-registered, held-out confirmatory run (OSF osf.io/8ecau) validated the estimator on a synthetic data-generating process. Real-data and external validity are a separate, ongoing question.

Relationship to MDStatR

rolescry began as a variable-role detection component written during development of MDStatR, an unreleased personal research codebase by the same author. It was separated into an independent project and is released on its own terms.

Version 0.2.0 rebuilt part of the detection engine on an information-theoretic basis (measurement-pair and outcome detection on minimum description length scoring over a distance-correlation backbone, an additive-noise-model direction test, a bit-margin abstention rule). Version 0.3.0 moves three more roles onto derived criteria: group_var (normalized Shannon entropy), paired versus agreement pairs (the sign of the MDL shift bits) and ordinal scale_items (a one-factor Gaussian two-part code). Three rules remain on the original ported signature scorers -- survival, wide repeated_measures and binary-item scale_items -- because derived replacements were measured and rejected under a no-regression rule (see Known limitations); the source files record provenance individually.

For anyone evaluating or using rolescry, the practical position is:

• No dependency. rolescry requires only base R (stats, utils). It does not import, link to or call MDStatR, and MDStatR is not needed to install, run, test or understand it.
• No overlapping distributed software. MDStatR is not publicly released and is not installable; it is archived on Zenodo as a record only. No other package duplicates rolescry's functionality.
• Its own contracts and evidence. The relabeling-invariance and permutation- equivariance guarantees, the test suite that enforces them, and the pre-registered evaluation belong to rolescry and have no counterpart in MDStatR.

The MDStatR reference is retained to attribute intellectual origin, nothing more.

Installation

From CRAN:

install.packages("rolescry")

From r-universe (development builds):

install.packages("rolescry", repos = "https://canboynukara.r-universe.dev")

From GitHub:

# install.packages("remotes")
remotes::install_github("canboynukara/rolescry")

The package needs only base R + stats. Optional packages (readxl/openxlsx/haven for file reading; moments/diptest/stringdist for extra refinements) are used only if installed.

Quick start

library(rolescry)

set.seed(1)
n <- 200
pre <- rnorm(n, 10, 2)
d <- data.frame(
  arm  = rep(c("control", "treatment"), each = n / 2),  # balanced 2-level grouping
  pre  = pre,                                           # a measurement ...
  post = pre + rnorm(n, 1, 1),                          # ... repeated after (paired)
  z1   = rnorm(n),                                      # two standardized predictors
  z2   = rnorm(n)
)
d$resp <- rbinom(n, 1, plogis(1.2 * d$z1 + 1.2 * d$z2)) # binary outcome caused by z1, z2

res <- detect_roles(d)
res$roles$group_var$columns        #> "arm"
res$roles$paired_pairs$columns     #> "pre" "post"
res$roles$outcome_binary$columns   #> "resp"
res$roles$covariate$columns        #> "z1" "z2"   (columns no other role claimed)
summary(res)

The name-blindness guarantee

Detection is purely mathematical by default (name_bonus = NULL):

pos <- function(res, dat) match(res$roles$outcome_binary$columns, names(dat))
d_blind <- setNames(d, paste0("col_", seq_along(d)))
identical(pos(detect_roles(d), d), pos(detect_roles(d_blind), d_blind))
#> TRUE  -- the SAME columns (by position) are detected, named or col_N

Column names can be used only as a small, capped tie-breaker (at most a +10 point nudge, i.e. <= 10%) by passing a keyword dictionary; the mathematical signature still dominates:

detect_roles(d, name_bonus = rolescry_default_name_bonus())

Header-aware loading

df <- read_data("messy_export.xlsx")   # auto-detects the header row

Beyond biostatistics

The detectors are information-theoretic, not domain-bound. The same calls work on financial data:

# a loan book: duration in months, rare default indicator
set.seed(31); n <- 1000
dur <- round(rweibull(n, 1.2, 36)) + 1
def <- rbinom(n, 1, plogis(-1 - 0.08 * dur))
loans <- data.frame(amount = rlnorm(n, 10, 0.6), rate = rnorm(n, 0.08, 0.02),
                    dur = dur, def = def)
detect_roles(loans)$roles$time_variable$columns   #> "dur"   (duration/event pair)

# a daily price series: the Date column is a calendar axis (time_index)
prices <- data.frame(dt = as.Date("2024-01-01") + 0:199,
                     price = cumsum(rnorm(200)) + 100)
detect_roles(prices)$roles$time_index$columns     #> "dt"

# finance keyword dictionary for the optional name hint
detect_roles(loans, name_bonus = rolescry_default_name_bonus("finance"))

Verifying a declared analysis plan

verify_roles(data, claim) turns the detector around: you state which columns play which role, and the data are asked whether they can support it. The check is name-blind (the claim is mapped to column positions once) and returns one verdict per claimed role.

set.seed(21); n <- 300
arm <- rep(c("drug", "placebo"), each = n / 2)
base <- rnorm(n, 150, 15)
rct <- data.frame(id = sample.int(99999, n), arm, age = round(rnorm(n, 60, 10)),
                  sbp_base = base, sbp_end = base - 10 * (arm == "drug") + rnorm(n, 0, 8))
rct$y <- rbinom(n, 1, plogis(-1 + 0.05 * (rct$sbp_end - 140)))
verify_roles(rct, list(subject_id = "id", group_var = "arm", paired_pairs = c("age", "sbp_end"),
                       outcome_binary = "y"))
#> <role_verification> 4 claims: 2 testable, 1 contradicted, 1 consistent, 2 unverifiable
#>            role      columns      verdict      sub_reason   statistic
#>      subject_id           id   consistent            <NA> unique=TRUE
#>       group_var          arm unverifiable identifiability     B=1.000
#>    paired_pairs age, sbp_end contradicted            <NA>  bits=-57.8
#>  outcome_binary            y unverifiable identifiability    unique=2
#>                                                                                  reason
#>            Every observed value is distinct and the column has an identifier signature.
#>  The data cannot say whether a column is the grouping; the entropy balance is reported.
#>  The two columns share no information beyond the independence noise floor (bits=-57.8).
#>                             The data cannot say which two-valued column is the outcome.
#> Structure not in the claim:
#>   paired_pairs       sbp_base, sbp_end (bits=240.1)
#>   coupled_pair       sbp_end, y (pct=69)

• contradicted: a falsification backed by a value statistic. Here age and sbp_end share no information, so they cannot be a pre/post pair. The exact conditions: subject_id values repeat while a detected long panel has another entity cluster; a paired/agreement pair shares no information, differs more than it agrees, or has a constant member; a coupled_pair whose members are independent; an event column that is not a two-level or 0/1/2 coding, or negative times; repeated_measures that are not a detected panel's measures, or a wide set with no common factor; ordinal scale_items with no common factor, or binary items forming a one-hot partition; a time_index that is not a calendar column; an all-distinct or calendar group_var; a non-numeric outcome_continuous; an outcome_binary without exactly two observed values. A false alarm costs a reviewer one read of the reason; a missed error costs far more.
• consistent: the data support the reading, never "correct". For a pair it means the two columns share information and their difference is smaller than their mean. Binary scale items are never consistent.
• unverifiable (identifiability): design roles (group_var, outcome_*, covariate) are not functions of the joint distribution (Lemma 2), so the data cannot confirm them.
• unverifiable (coverage): the package has no test for the situation, or the evidence is empty (all-NA, fewer than 10 complete cases, non-numeric). No time-event association is also coverage, not a contradiction: constant-hazard censoring makes the event independent of the observed time.
• Each claimed pair is judged on its own. A survival claim (time plus event) is one claim shown as two rows and counted once.
• Structure not in the claim lists what the blind detector found that the claim does not state under the same role (covariates excluded): here the real pair sbp_base/sbp_end.

Aligning roles across sites without a codebook

Pooling data from several centers starts with finding which column plays which role in each file. harmonize_roles(sites) runs the name-blind detector on every site and tabulates, per role, the column each site holds (aligned = found everywhere, partial, absent). Here the two sites share no column names and the order differs, and the event is coded 0/1 at one site and 1/2 at the other.

site <- function(seed, nm, n = 200, code = 0:1) {
  set.seed(seed); b <- rnorm(n, 150, 15); t <- rweibull(n, 1.3, exp(5 - rnorm(n)))
  cens <- runif(n, 0, quantile(t, .9))
  d <- data.frame(sample.int(99999, n), sample(c("a", "b"), n, TRUE), b, b - 5 + rnorm(n, 0, 6),
                  round(pmin(t, cens), 1), code[1 + (t <= cens)])
  setNames(d, nm)
}
north <- site(1, c("id", "arm", "sbp_base", "sbp_end", "time", "dead"))
south <- site(2, c("pid", "group", "bp0", "bp1", "ftime", "status"), code = 1:2)[, c(3, 1, 6, 2, 5, 4)]
harmonize_roles(list(north = north, south = south))
#> <role_harmonization> 2 sites: 5 aligned, 0 partial roles
#> 
#>            role  status             north    south
#>       group_var aligned               arm    group
#>    paired_pairs aligned sbp_base, sbp_end bp0, bp1
#>   time_variable aligned              time    ftime
#>  event_variable aligned              dead   status
#>      subject_id aligned                id      pid
#> 
#> Flagged and overlap checks
#>           role         check north south flag
#>      group_var level_jaccard  1.00  1.00 <NA>
#>  time_variable range_overlap  0.72  0.72 <NA>
#> 
#> Descriptive checks (levels, Jaccard, ranges) are in $checks; flags mark structural mismatches only.

• map is the table above; checks adds descriptive rows per role found in two or more sites (value type, event levels and coding, group-label Jaccard, range and range overlap, battery size); site_only lists roles found at one site only.
• Only categorical facts are flagged: type_mismatch, coding_mismatch (the normalized event coding differs: 0/1, 1/2 and TRUE/FALSE normalize to the same two-level shape, which level is the event is not checked; a 0/1/2 status differs) and size_mismatch (item counts differ). Jaccard and range overlap are reported, never flagged, and no numeric threshold decides a flag.
• Alignment is by role only; names appear in the output cells. The residual covariate role is excluded.
• aligned means the detector found the role at every site; it does not establish that the columns measure the same thing; read checks (levels, Jaccard, ranges) before pooling. Cell order is alphabetical and carries no pairing direction.

Known limitations

• A numeric-coded treatment (0/1) is not distinguishable from a numeric covariate from the data alone; group_var is detected for character/factor groupings.
• A binary outcome with a strictly positive continuous cause can carry the same value signature as a survival time/event pair; the package may then report a survival pair.
• When a positive, right-skewed column is strongly associated with a two-valued column that is not the documented event (e.g. survival::veteran, diagtime/prior), that pair is reported instead of the documented one. Name-blind, the two cannot be told apart.
• The binary-outcome evidence is a two-part MDL code (0.3.0): each admitted cause must pay its parameter bits plus the bits naming it among the m candidates, which keeps phantom outcomes on pure noise to roughly 6% of tables -- at the price that a weak, borderline true cause may stay honestly silent.
• When the paired-measurement scorer latches onto a (cause, outcome) column pair, the continuous outcome can be claimed by paired_pairs and stay silent; lifting that exclusion was measured to misassign more outcomes than it recovered.
• Paired versus agreement is the sign of the MDL shift bits of the single best pair, a BIC-type test of a mean difference between the two columns. agreement_pairs therefore means "no detectable systematic shift": biased method-comparison (Bland-Altman) data with a real calibration bias is labeled paired_pairs, and the label is n-dependent (a 0.5-unit bias at SD 15 flips from agreement to paired between n of about 200 and 1000). About 3% of unbiased pairs at n = 100 read as paired under the null. Exactly one pair is reported across the two roles.
• name_bonus adds 10 points on the 100 * B group scale, where candidates usually differ by 1-5 points, so a group keyword hint is decisive in practice (a no-op under NULL).
• Unequal allocation: a 2:1 arm can lose the group ranking to a more balanced binary covariate (a documented ceiling of the entropy ranking).
• Survival, wide repeated_measures and binary-item scale_items still use the ported point scorers (pct >= 30). Survival: ranking pairs by association bits picks the strongest dependence (on survival::pbc, bilirubin/status), and every variant that repaired this added false positives to the survival roles. Wide repeated measures: a one-factor code on standardized columns measures shared variance only and discards the same-units structure (equal means and spreads across repeats) that the scorer uses; four block-growth variants raised false positives from 15 to 163-207 tables (dev-band measurement, pass 5). Binary items: an all-pairs dependence test rejected every simulated binary battery.
• For ordinal batteries of k <= 3 items the one-factor model is saturated (k = 2) or just-identified (k = 3), so the test there is only whether the items co-vary; unidimensionality is enforced for k >= 4.
• The ordinal scale_items candidate set is not pruned: a stray ordinal covariate can ride along with a real battery.
• A categorical column in which any level is observed fewer than 3 times is excluded from group_var candidacy.
• Accuracy has been confirmed on a synthetic data-generating process only; a pre-registered evaluation on held-out real data is planned.

How it works

detect_roles() types each column from its values (.build_var_info), scores candidate roles with information-theoretic and distributional signatures (compute_nmi() exposes the normalized mutual information directly), and returns a structured role_detection object with per-role confidence and a component breakdown. See vignette("rolescry") for the method and the name-blind guarantee.

Citation & attribution

rolescry has its own archival DOI: 10.5281/zenodo.21003941 (Zenodo). It is derived from the MDStatR engine: Boynukara, C. (2026). MDStatR (v2.1.0 Veritas). Zenodo. https://doi.org/10.5281/zenodo.20707791

Run citation("rolescry") to cite the package (with its archival DOI) and its parent engine.

License

Apache License 2.0.