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Evaluation vs Decision Assurance

An evaluation grades the run against what the run says. Decision Assurance grades the run against what happened.

In one sentence

Evaluation reads the record the system produced and judges it; Decision Assurance compares that judgement against the outcome the world later returned. They answer different questions, and a serious system runs both.

The objection worth answering

The common response to all of this is reasonable: if my evaluations check the right things, why do I need anything else?

The answer is that "if my evaluations check the right things" is the assumption in question. There is only one way to find out whether they do, which is to compare what they said against what actually happened. You cannot validate an evaluation suite with more evaluations. Every suite running in production today is uncalibrated to some unknown degree, because nothing ever checks it against reality. That is not a criticism of anyone's evaluations. It is a description of what evaluations are.

Three things an evaluation cannot do, however good it is

1. The answer does not exist yet. An evaluation is a function of the record in front of it. At the moment it runs, whether the refund settled, whether the claim was reopened on appeal, whether the shipment arrived, none of that has happened. That information arrives later, from a different system. This is not a gap in coverage that better rules would close. Perfect rules cannot read facts that do not exist yet.

2. There is no independent witness. The agent produces the record. The evaluation reads the record. Both sides of that check come from the same source. Decision Assurance introduces a second one, the operator's own system of record, and that is what makes the claim falsifiable. An evaluation score cannot be wrong in any way that shows up. A prediction about an outcome can.

3. A rule can only catch a failure someone already imagined. Every check encodes a failure mode a person thought of and wrote down. Comparing against the settled outcome catches the ones nobody thought of, without anyone having to anticipate them first. This is the limit that survives the assumption of perfect rules, because the rule you did not write is not a rule you wrote badly.

What this looks like in practice

A support agent processes a refund. It reads the account, applies the policy correctly, and replies that forty dollars is on its way back to the card. The tool it called to move the money answers normally: no error, no timeout, a well-formed response. Every check passes, because everything the checks can see is genuinely fine.

Inside that normal-looking response, the payment did not go through. The bank returned it. The customer does not have their money, and the only record that says so arrives days later in the operator's own books.

An evaluation catches this only if somebody had already written a check for that exact field on that exact tool. And if they had known to do that, they would have fixed the underlying problem instead of writing a check for it. Nothing about the agent's behaviour was wrong. The tool call was healthy. The outcome was not.

This is why a tool can show a perfect record on every call it makes and still be the reason a result was wrong. Those are two different measurements, and an evaluation only ever sees the first.

Business context

The confusion has budget consequences. Teams invest heavily in an evaluation suite, watch the scores stay high, and conclude the system is safe to scale. The score was never measuring that. For a leader, treating a strong evaluation number as proof of production results is how an automation programme looks healthy right up to the incident that reveals nothing was ever checking the outcome.

The practical question to ask of any agent programme is not "what do the evaluations say". It is "by how much are the evaluations wrong, and how would we know". A programme that cannot answer the second question does not really have an answer to the first.

Side by side

DimensionEvaluationDecision Assurance
What it reads The record the system produced That record, and the outcome the world returned
When it can run Immediately, before the outcome exists Only once the outcome has settled
Source of truth A rule or reference answer someone wrote The operator's own system of record
Can it be proven wrong? No. Nothing later contradicts a score Yes. The outcome either matched the prediction or it did not
What it misses Failures nobody anticipated, and anything that only settles later Failures on cases that have not reached production yet
Can it block an action? Yes, before the action happens No. It is inherently after the fact

Why you need both

Neither replaces the other, and the case for Decision Assurance does not depend on evaluations being weak. Evaluation is how you catch a regression before it ships, and how you probe cases too rare or too dangerous to wait for in production. It is immediate, cheap, and it can stop an action in flight. Decision Assurance cannot do any of that, because it needs an outcome that has not happened yet.

What Decision Assurance adds is the only external check in the system. Ship on evaluation alone and you are trusting that your rules represent reality, with nothing to tell you when they stop. Run outcome checking alone and you have no way to test a change before it reaches customers. One guards the release. The other guards the result.

The short version: evaluations tell you the agent behaved correctly. Decision Assurance tells you it was actually right. Most programmes today have the first and none of the second.

Common misunderstandings

It is not that your evaluations are bad. This is the most frequent misreading. The argument holds even if every rule is well written and covers exactly the right policy. The limits described above are properties of what an evaluation is, not of how carefully it was authored.

It is not that one replaces the other. A strong evaluation suite does not remove the need to check production outcomes, and outcome checking does not remove the need to test before release.

It is not that a high score means production is safe. The score reflects what the rules looked for, not what the world sent.

It is not the same as monitoring. Monitoring confirms the run happened and stayed healthy. Neither monitoring nor evaluation grades whether the settled outcome was right.

It is not solved by adding more evaluations. More rules extend the set of failures you anticipated. They do not create a second source of truth, and they do not tell you how far the existing rules are from reality.

Where it fits

Decision Assurance is built on reconciliation of the real business outcome, which is exactly what evaluation, reading only the record the system produced, cannot reach. It is the discipline that catches a silent failure an eval-only pipeline scores as a pass, and the gap it measures is Estimated vs Reconciled.

Related concepts

In the product

Where this shows up in Provy. Provy sits after the eval, reconciling live decisions against their outcomes, so it complements an evaluation suite rather than replacing it. How the two signals combine is an implementation detail this library does not cover. See the product →

Related insights

Further reading

  1. Provy Research. Why observability isn't enough.
  2. Provy Research. Decision Assurance.
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