Independent AI verification means the check is not the vendor's own model.

Two models trained on similar material share blind spots, and a review prompt invites agreement. The output looks approving, lists a few cosmetic suggestions, and misses the invented statistic sitting in the second paragraph because the same distribution that produced it would also produce the review.

The failure is quiet. There is no error, no warning and no disagreement to investigate. A team that asked a model to check a model's work gets a document that says it was checked.

Replacing the second model with a deterministic rule engine changes the failure mode entirely: the rules were written before the output existed, and they do not know what the output was trying to say.

Independence is a set of testable properties rather than a stance. If a verification process has them, its agreement means something; if it lacks them, the agreement is decoration.

A deterministic check can be argued with. Each finding names a rule and the line that triggered it, so a disagreement has a location: the rule is too strict, the pattern is in a test fixture, the severity is wrong for this codebase.

That argument is impossible against a model score, where the number is produced by a process nobody can inspect and may change when the vendor updates a weight. You cannot appeal to a judgement that has no reasons.

Determinism also makes external audit cheap. An auditor can take the text, run the same version, and see the same page, which turns a claim about quality into a reproducible experiment.

A named reviewer is independent when you can see who they are, what they review, what they charge and when they are available, and when they are accountable for the verdict they sign.

That rules out the anonymous pool, the reviewer who exists only as a first name and an avatar, and the marketplace that assigns work behind a curtain. It also rules out a reviewer whose incentive is to approve quickly, which is why the scope and rate are agreed before the file is opened.

The record keeps the reviewer's discipline and the changes they requested, so months later the question who signed this has an answer with a person and a date.

The automated report proves the absence of specific known defects, with coverage listed. The human sign-off proves that someone competent in the discipline read the work in context and accepted it.

Alone, each is weak. A green report with no reviewer is a machine saying it found nothing in the places it looked. A review with no automated pass is a specialist spending their hour reading for credentials that a regex finds in a second.

Together they are what a delivery or an audit actually needs: a mechanical baseline and an attributed judgement on top of it.

Independence does not mean detached from your context. A reviewer who does not know your product, your regulator or your audience will produce a general opinion, and general opinions are cheap.

It also does not mean infallible. A named specialist can miss something, which is why the report keeps the findings, the scope and the version rather than a single badge that says approved.

The realistic goal is a process where every claim has an owner, every finding has a rule, and the places nobody checked are written down rather than assumed away.

Claims of independence are cheap, so test the properties rather than reading the paragraph. Four checks take an afternoon and tell you more than a sales call.

Run the same input twice. A deterministic checker returns the same findings, the same severities and the same score. A model-judged one drifts, and the drift is the tell: if a re-run can disagree with the report you filed, the report was never evidence.

Read one rule end to end. You should be able to see what it matches, why the severity is what it is, and what it will miss. A vendor who cannot show you a rule is asking you to accept a verdict on the strength of their branding.

Ask who signs, and look for a name. A review that resolves to a pool, an avatar and a first name is not an attributed judgement, and it will not survive the first time somebody asks who approved the work. The same question applies to the record: does it keep the reviewer, the scope and the findings, or only a green badge?

Then compare the coverage against your own risk. Independence from the generator is necessary and not sufficient; a rule set that checks nothing you care about is independent and useless.