Reject Case Collision

Review ask

As a clinical trial statistician or programmer, challenge anything in this benchmark: describe a problem in Comments, or propose a fix with the Edit button on any source file.

Task: Is this a specification error a study team could realistically make, and should the build stop on it rather than continue?
Inputs: Do they trigger the failure for the reason the summary gives?
Expected failure: Is this the right error, raised at the right point, and would it tell the programmer what to fix?

The other tabs beside Comments are background for assessment, not under review.

Summary

EditUnder reviewWhat this benchmark means

README.md

Goal: build SMOKEFL from collected smoking status, matching without regard to case.

Input: collected demographics carrying reported smoking status (SMOKSTAT).

Variables:

SMOKEFL would be the smoking flag taken from SMOKSTAT without regard to case: Y gives Y, y gives Y, and N gives N. The entries for Y and y collide on the key Y once case is ignored, so the run is rejected before any data is read and no artifact is accepted.

How to fix

For case-insensitive matching, retain only one dictionary entry for each folded key. Both Y and y then resolve through Y:

mapping:
  source: DM.SMOKSTAT
  case_sensitive: false
  dict:
    Y: "Y"
    N: "N"

Alternatively, set case sensitivity on when differently cased values are intentionally distinct and give each one an explicit meaning.

Expected failure

Editthe run is rejected; no artifact is accepted

expected/error.yaml

phase: validation
condition: ambiguous_dictionary
requirement: REQ-0714

expected/error.yaml

phase: validation
condition: ambiguous_dictionary
spec_paths:
  - columns.SMOKEFL.derivation.mapping.dict
requirement: REQ-0714
context:
  folded_key: "Y"
  entries: ["Y", "y"]

YAML specification

1 spec file

spec.yaml

Edit34 lines

1schema_version: "1.0"2domain: ADSL3keys: [STUDYID, USUBJID]4input:5  DM: input/dm.csv67output:8  path: adsl.csv9  columns: [STUDYID, USUBJID, SMOKEFL]1011columns:12  - name: STUDYID13    type: str14    label: Study Identifier15    derivation: DM.STUDYID1617  - name: USUBJID18    type: str19    label: Unique Subject Identifier20    derivation: DM.USUBJID2122  # Case is ignored, so the keys Y and y both fold to Y: the dictionary23  # has two entries for one key.24  - name: SMOKEFL25    type: str26    label: Smoker Flag27    derivation:28      mapping:29        source: DM.SMOKSTAT30        case_sensitive: false31        dict:32          Y: "Y"33          y: "Y"34          N: "N"

Inputs

Under review1 source file

input/dm.csv

Edit2 rows

input/dm.csv
STUDYID	USUBJID	SMOKSTAT
PILOT7		Y
PILOT7		y

Unexpected Output

Under reviewNo artifact is produced

No fixture files in this directory.

Shaded columns are derived— = missing value

Comments and assessment materials

Dataset Name	Variable Name	Variable Label	Type	Computational Method	Origin
ADSL	STUDYID	Study Identifier	character	Copy value from DM.STUDYID.	Predecessor
ADSL	USUBJID	Unique Subject Identifier	character	Copy value from DM.USUBJID.	Predecessor
ADSL	SMOKEFL	Smoker Flag	character	Recode DM.SMOKSTAT: "Y" → "Y", "y" → "Y", "N" → "N"; missing or unlisted values are errors; matching ignores letter case.	Derived

Version	Date	Author	Description
1.3	2026-09-29	yamaa docs build	Show study codelist names, external dictionaries, and ISO 8601 formats in variable rows; list the document's codelist values and metadata
1.2	2026-09-29	yamaa docs build	Classify ADaM copies from a declared input as Predecessor and recodes as Derived, and SDTM recodes of locally derived columns as Derived
1.1	2026-09-29	yamaa docs build	Resolve lookups into the donor record they select, and give every derivation shape a plain-language rule instead of its raw YAML
1.0		yamaa docs build	Initial generation from spec.yaml

How to fix

input/dm.csv

Comments

Mapping spec