Derive Date Epoch

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: Would a real study need this derivation, specified this way? Does it follow CDISC ADaM: variable names, controlled terms, record structure? Flag any rule that is ambiguous or that a sponsor would handle differently.
Inputs: Do they look like data collected in a real trial, and do they include the situations you would expect to meet in one?
Expected output: Would independent QC programming reproduce every value from these inputs and rules?

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

Summary

EditUnder reviewWhat this benchmark means

README.md

Goal: demonstrate the per-record derive step of an aggregation: convert each record's date to an integer day count with to_epoch_day, then summarize the integers.

Input: exposure records with sequence numbers (EXSEQ) and start dates (EXSTDT). Only the record with sequence number 1 becomes an output row.

Variables:

EXSEQ: the exposure sequence number, carried through.
EXSTDY: the exposure start date as a count of days since 1970-01-01 (zero on that day, negative before it), blank when the start date is missing. It is not a day counted from a reference start.

Note: each matching exposure record's date is turned into its day count first, so the summary works on plain integers and never on dates. The summary then keeps the value of the one record with the row's subject and sequence number (ONLY); a second matching record would stop the run.

YAML specification

1 spec file

spec.yaml

Edit50 lines

1schema_version: "1.0"2domain: ADEX3keys: [STUDYID, USUBJID, EXSEQ]4input:5  EX: {path: input/ex.csv, types: {EXSEQ: int, EXSTDT: date}}67output:8  path: adex.csv9  columns: [STUDYID, USUBJID, EXSEQ, EXSTDY]1011columns:12  - name: STUDYID13    type: str14    label: Study Identifier15    derivation: EX.STUDYID1617  - name: USUBJID18    type: str19    label: Unique Subject Identifier20    derivation: EX.USUBJID2122  - name: EXSEQ23    type: int24    label: Sequence Number25    derivation: EX.EXSEQ2627  # Reads the EX records with this row's STUDYID, USUBJID and EXSEQ. The28  # derive step turns each record's start date into days since 1970-01-0129  # before reduction; ONLY takes that one value and fails on a second match.30  # The value is an epoch day, not a study day.31  - name: EXSTDY32    type: int33    label: Epoch Day of Exposure Start34    derivation:35      aggregate:36        key: [STUDYID, USUBJID, EXSEQ]37        derive:38          - name: EPOCHDAY39            type: int40            derivation:41              to_epoch_day:42                source: EX.EXSTDT43        expr: "ONLY(EPOCHDAY)"4445rows:46  # One output row per EX record with sequence number 1; every column above47  # is derived for it, so the row template sets nothing itself.48  - id: exposure49    filter: "EX.EXSEQ = 1"50    derivations: {}

Inputs

Under review1 source file

input/ex.csv

Edit3 rows

input/ex.csv
STUDYID	EXSEQ	EXSTDT
PILOT7	1	2024-01-15
PILOT7	2	2024-01-16
PILOT7	3	2024-01-17

Expected output

Under review1 expected row

expected/adex.csv

Edit1 row

expected/adex.csv
STUDYID	USUBJID	EXSEQ	EXSTDY
PILOT7		1	19737

Shaded columns are derived— = missing value

Comments and assessment materials

Dataset Name	Variable Name	Variable Label	Type	Computational Method	Origin
ADEX	STUDYID	Study Identifier	character	Copy value from EX.STUDYID.	Predecessor
ADEX	USUBJID	Unique Subject Identifier	character	Copy value from EX.USUBJID.	Predecessor
ADEX	EXSEQ	Sequence Number	numeric	Copy value from EX.EXSEQ.	Predecessor
ADEX	EXSTDY	Epoch Day of Exposure Start	numeric	Aggregate ONLY(EPOCHDAY) over records matching on STUDYID, USUBJID and EXSEQ, with EPOCHDAY as days since 1970-01-01 for EX.EXSTDT.	Derived

Template	Include when
exposure	EX.EXSEQ = 1

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

run.R

Edit4 lines

1library(yamaa)23adex <- yamaa_domain("spec.yaml")$output4adex

run.py

Edit4 lines

1import yamaa23adex = yamaa.yamaa_domain("spec.yaml").output4adex

input/ex.csv

expected/adex.csv

Comments

Mapping spec

yamaa code

run.R

run.py