Evaluation holdouts review packet: nine metadata documents to assemble before a sealed test set is reviewed

Short answer

An evaluation holdouts review packet is a set of nine metadata-only documents that lets SourceX judge whether a company's archive could supply a sealed test set, without anyone outside the company seeing a case or an answer. In order: a cover sheet, the task statement, a cutoff memo, the outcome mix, a description of the answer key, a custody statement, an access-history summary, the scoring rule and rights notes. Each is written by the person who already holds that fact.

Visual briefFull-size diagram
Nine labelled documents, from cover sheet to rights notes, slide one after another into an open review folder marked metadata only, with the answer key description shown under a seal.
Illustrative packet order for a fictional freight invoice audit holdout. The folder holds descriptions, counts and dates, never cases or answers.

This contents list is part of the evaluation holdouts guide for introducers, which covers the discovery questions to ask first. This page picks up after those answers come back positive: it lists what the company assembles, in what order, and who holds the pen. It is a working document for the owner's team, not a script for the introducer.

Nine documents, in assembly order

The order follows the logic a reviewer uses. First, what is being tested. Then, which cases are in scope and what their answers look like. Then, the proof that nobody has seen those answers. Last, how a test is scored and who may license it.

#DocumentWhat it showsWho prepares it
1Cover sheetHeadcount at peak, case system, years of history, named owner and contactOwner or COO, with the introducer helping only on these metadata fields
2Task statementThe single decision a system under test would be asked to makeHead of the audit or operations team
3Cutoff memoThe date that splits a possible training pool from the reserved window, and whyOperations lead, with IT confirming close dates are locked
4Outcome mixCounts of each final outcome inside the reserved windowReporting analyst
5Answer key descriptionWhich fields make up the answer, where each is stored, how reversals are capturedOperations lead and system administrator
6Custody statementEvery place the archive has been copied: vendors, pilots, outsourcers, prior dealsIT and procurement, reviewed by counsel
7Access-history summaryWhether the system logs who opened case records, and for how longIT or security
8Scoring ruleWhat counts as a correct answer, written before any case is drawnAudit lead, reviewed by SourceX
9Rights and sensitivity notesCustomer contract limits, personal data present, carrier or vendor termsCounsel or CFO

Every entry is a description, a count, a date or a name. None is a record. If a document cannot be completed, the honest move is to write "not known yet" and say who would know.

The test card behind the packet (Illustrative)

Documents 2 to 5 together describe one candidate test set. Here they are for a fictional 280-person freight audit and payment company that checks carrier invoices against contracted rates and shipment records before paying them for shippers. The live overview of freight audit exceptions describes the record family in general; every number below is invented.

Packet itemEntry on the test card
Task statementAudit a carrier invoice against the rate agreement and shipment record; approve as billed, short-pay with a corrected amount, or dispute with a reason code
Reserved windowInvoices closed January 1 to June 30, 2026
Earlier poolInvoices closed 2018 to 2025, which could be discussed separately for training and never mixed with the window
Candidate holdout size300 invoices, drawn to match the real outcome mix
Outcome mix210 approved as billed, 66 short-paid, 24 disputed
Answer key fieldsAuditor's final decision, amount paid, reason code, and whether the carrier accepted or contested
Isolation ruleNothing closed on or after the cutoff enters any training set; key stored apart from case inputs
Assessor access (proposed)Left to the agreement; the company's preference is that an independent assessor runs the test and reports only scores

The test card is the heart of the packet because it turns "we have an archive" into a specific, checkable claim: this window, this many cases, this answer, kept this way. A company that can fill every row in plain language is ready for review. A company that cannot fill the answer key row has found its first gap, which the companion page on evaluation holdout evidence gaps helps describe.

Sealing the answer key: documents 5 to 7

A holdout is only worth anything if the system being tested has never seen the cases or their answers. Research shows why reviewers insist on proof. When researchers built GSM1k, a fresh held-out set mirroring the widely used GSM8k math benchmark, some models scored up to 8% lower on it, with signs of systematic overfitting in several model families, while frontier models showed minimal signs of it. LiveBench takes another route to the same goal, refreshing its questions from recent sources and scoring them automatically against objective answers. Both depend on knowing when material was created and who has had it. Documents 5 to 7 carry that knowledge for a private archive.

Document 5, answer key description. Lists the fields, not their values. For the freight case: decision code, paid amount, reason code, carrier response, and the date of the last change. It must say how a later reversal is stored. If a short-pay was contested and the carrier won, the key has to hold the settled amount, or the test will mark a correct system wrong.

Document 6, custody statement. A plain list of every copy that ever left the company, with dates. "A 2022 pilot with an invoice-scanning vendor received 2021 to 2022 invoices" is a useful sentence. "Probably nothing" is not. A past share usually narrows the window rather than ending the discussion.

Document 7, access-history summary. Says whether the case system records who opened records and how long those logs are kept. It does not attach the logs. The point is to show that "unseen" could be demonstrated later, under an agreement, not merely asserted.

Scoring rule and the exact outcome check

Document 8 states what a correct answer is, written before anyone draws a case. A rule drafted after looking at outcomes tends to fit whatever the archive happens to contain.

For the freight test card, the rule reads:

  • The decision (approve, short-pay, dispute) matches the auditor's final decision.
  • For short-pays, the corrected amount is within one dollar of the amount finally paid.
  • For disputes, the reason code matches the key.
  • Where the carrier contested and the outcome changed, the settled result is the answer, not the first decision.

The last line is why carrier responses belong in document 5. Scoring is easy here because answers are close to binary; where answers are judgment calls, the guide to rubric-based evaluation shows how scoring criteria are written instead. The live explainer on what model evaluation is covers why developers pay attention to tests like this.

A holdout is often licensed for evaluation only, a narrower use than training. The comparison of an evaluation-only data license with a training license sets out the usual differences, which document 9 should anticipate.

Who signs off, and what the packet leaves open

Ownership usually splits three ways: the audit or operations team owns cases and decisions, IT owns the system and its logs, and finance or counsel owns customer and carrier contracts. Authority to discuss a license, for evaluation-only or training use, sits with the CEO (in an owner-run company, the owner); the CFO or COO can sponsor the introduction. Document 1 names the CEO as the authorized contact.

The company itself must qualify: 50 or more full-time employees at peak (contractors excluded), documented operating history, rights to license, and an authorized contact. Companies in the U.S., Canada and the EU qualify, as do companies in the UK, Australia, New Zealand, India, Singapore, South Africa, Latin America, the UAE and Saudi Arabia when at least 90% of the data is in English.

Partners never assemble the packet, and never receive cases, exports, logs or screenshots. Their part ends at the metadata on the cover sheet: what exists, how much, how long, which system, who owns it. What the packet cannot settle: whether the custody statement holds up, how many cases survive de-identification, whether customer contracts permit the use, whether a buyer wants this task, and therefore any offer or reward. Those are decided in SourceX's review. For a sense of how one archive is split in practice, see the evaluation holdouts workflow example.

Next step

Refer a company. Earn up to $100,000. Default reward: 25% of Actual Supplier Payout, capped at $100,000 cumulatively per referred company. Eligibility and payment conditions apply, and a signed Schedule A or addendum can differ. A lead, meeting or signature alone does not trigger payment.

If the owner's team could complete the test card and custody statement above from what they already know, register as a partner, confirm the company against who qualifies, and read the terms before introducing the CEO, who can approve evaluation-only use.

  1. Step 1Share your linkSend your personal link to a company you know.
  2. Step 2Company appliesThe company applies itself at /apply.
  3. Step 3Company signs and is paidThe company signs, delivers its data and is paid by SourceX under its agreement.
  4. Step 4You get your rewardYour 25% of the actual supplier payout. A reward becomes payable after SourceX has paid the referred company under its signed agreement and the payout conditions in the program terms are met, including finance approval and your tax and payment details.

Common questions

Does the packet include the holdout cases themselves?

No. It describes the cases: the date window, the count, the outcome mix and the fields in the answer key. The cases and their answers stay inside the company until an agreement is signed, and then move only under that agreement.

Who writes the cutoff memo?

Usually the operations lead who owns the case system, with IT confirming that close dates cannot be edited. The memo is short: the cutoff date, why it was chosen, and which earlier years could be offered separately for training.

What if the archive was shared with a vendor once?

List it in the custody statement with the years affected. A past share does not end the discussion; it usually means those years are excluded from the holdout window and the remaining period is assessed on its own.

Sources

  1. proceedings.neurips.cc/paper_files/paper/2024/hash/53384f2090c6a5ca…
  2. proceedings.iclr.cc/paper_files/paper/2025/hash/e4a46394ba5378b3…
  3. refer.sourcex.si/terms

Free resources

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