Writing Rubrics That a Judge Can Apply Consistently
LLM-judge calibration checks a judge's grades against a set of handlabeled contracts so that trust is based on measured agreement rather than assumption.
When Human Grading Stops Scaling
Imagine a legal team that must grade a large number of contracts against a set of criteria. The source describes exactly this situation. The grading effort would have stalled at the original forty-two cases without help. The deputy general counsel could grade five contracts an hour at most, while the team needed grading capacity in the hundreds per week, and that need grew as the prompt was iterated.
A human reviewer cannot keep up with that volume, so the team considered an LLM-judge: a model used to grade the contracts in place of a person. The obvious question is whether the judge can be trusted. Calibration is the process of answering that question with evidence rather than with hope. This article follows how the source team did it, and why the answer turned out to be different for different criteria.
Tracing the Inputs to a Calibration Run
Before looking at any numbers, it helps to follow what goes into a calibration run and what comes out. There are two sources of grades. The first is the handlabeled set, the contracts that the deputy general counsel had graded by hand. In the source, this set contained fifty contracts. The second is the judge's grades, produced by the LLM-judge for those same contracts. Calibration brings these two sets together so they can be compared one criterion at a time.
Notice that the judge is never asked to justify itself in isolation. Every judge grade is measured against a human grade on the same contract. The human-labeled set is the reference point, and the output is an agreement percentage for each criterion rather than a single overall score.
Agreement as the Measure of Trust
LLM-judge calibration checks a judge's grades against a set of handlabeled contracts so that trust is based on measured agreement rather than assumption.
Agreement here means the degree to which the judge's grade matches the human grade for the same contract on the same criterion. Because the source reports agreement as a percentage, the team could compare criteria directly. A high agreement percentage on one criterion says nothing about another criterion, which is why the source keeps the results separate.
Trust is decided criterion by criterion. The source trusted the judge on C1 at ninety-four percent agreement, but kept C2 manual at seventy-one percent. A judge can be reliable on one criterion and unreliable on another in the same run.
Calibration as a Loop, Not a Final Test
Calibration was not a single test at the end of the project. The source states that the judge took six iterations to get into useful range before it was useful at all. Each pass followed the same loop: check the judge's behavior against the handlabeled set, revise the grading instructions, and check again.
The loop has a clear structure. A criterion is measured. If agreement is not high enough, the criterion stays with the human reviewer, the rubric is revised, and the agreement is measured again. The same criterion can therefore pass through several rounds before a decision is made about it.
- 1Grade the handlabeled contracts with the judge on one criterion
- 2Compare the judge grades with the human grades and compute agreement
- 3If agreement is not high enough, keep that criterion manual
- 4Revise the rubric instructions for that criterion
- 5Measure agreement again and repeat until the criterion stabilizes or is trusted
Routing Each Criterion to Automatic or Manual Grading
Once agreement is measured for a criterion, the team must decide where that criterion is graded. The flowchart below shows the decision the source describes. If agreement is high enough, the criterion can be graded by the judge. If not, the criterion stays manual while the rubric is revised and re-measured.
Reading the Results for C1 Through C4
The source reports four criteria, and their results differ in a useful way. C1 is the hard-fail criterion, meaning that failing it fails the contract outright. Because of that role, the team needed the judge to agree with the human labels on C1 before trusting it there. Agreement reached ninety-four percent after two rubric revisions, which was high enough for the team to trust the judge on C1.
C2 shows what happens when agreement does not reach the bar. Agreement stalled at seventy-one percent, which the source describes as not high enough. The team kept C2 grading manual until the rubric stabilized, so the human reviewer continued grading that criterion while the judge was not yet trusted on it. A third pass, made once the rubric stabilized, brought agreement on C2 to eighty-six percent. The source does not describe the exact changes made to the C2 rubric.
C3 and C4 were different. Both calibrated cleanly from the first attempt because their instructions were crisp and mechanical. The judge matched the human labels without any rubric revisions. The source attributes this to the nature of the criteria themselves, not to any special tuning.
Reading the table this way shows the lesson of the source. A criterion can stall below the bar, the team can hold it back from automation, and it can later be brought into automated grading once the evidence supports it. Even C1 needed two revisions before its result was trusted, so calibration results should be read as the outcome of a process rather than as a property of the criterion alone.
Predicting Which Criteria Will Calibrate Cleanly
What do you think happens?
Before reading on: which criterion needed no rubric revisions to calibrate, and what kind of instruction does it probably have?
Reveal answer
C3 and C4 calibrated cleanly from the first attempt.
The source reports that C3 and C4 had crisp, mechanical criteria, so the judge matched the human labels without rubric revisions. The source frames this as a pattern observed in one case rather than a general law.
The contrast is useful for planning. Criteria that depend on clear, checkable features tend to calibrate quickly, while criteria whose instructions leave more room for interpretation may need several rounds of rubric revision. The source does not claim a general rule here, so use this pattern as a hypothesis to test on your own criteria rather than as a guarantee.
A Routing Decision Worked Through Step by Step
Deciding the route for a new criterion
A team calibrates a new criterion, C5, against its handlabeled contracts. The first measured agreement is seventy percent, and the instructions mention several interpretive judgments. Should C5 be graded automatically, and what happens next?
- 1Measure agreement
Compare the judge grades on C5 with the human grades on the same contracts, using only C5 for this result.
- 2Check against the bar
Seventy percent is closer to the stalled C2 result of seventy-one percent in the source than to the ninety-four percent that the team trusted on C1. The team judges it not high enough, consistent with the source's treatment of C2.
- 3Keep it manual
C5 stays with the human reviewer, so no automated grades are used for it yet.
- 4Revise and re-measure
The interpretive instructions are the likely source of disagreement, so the rubric is revised and agreement is measured again on the same handlabeled set.
C5 stays manual after the first pass. It may be routed to automatic grading only after a revised measurement shows agreement the team considers high enough.
Mistakes When Reading Calibration Results
Common mistake Trusting the judge because the overall score looks good
Why it failsThe source reports agreement per criterion. One strong criterion can hide a weak one, as C2 at seventy-one percent shows alongside C1 at ninety-four percent.
Do this insteadRead each criterion's agreement separately and make a separate routing decision for each.
Common mistake Treating the first calibration pass as the final answer
What it looks likeThe judge needed six iterations to reach useful range, and C2 only reached eighty-six percent after a third pass.
Why it failsCalibration is a loop of measuring, revising the rubric, and measuring again.
Do this insteadExpect several rounds, and re-measure after every rubric change.
Common mistake Assuming a criterion that calibrated well will always stay reliable
Why it failsTrust in a criterion depends on evidence from the handlabeled set at the time it was measured.
Do this insteadKeep the handlabeled set as the reference point and re-check agreement when the rubric changes.
Common mistake Assuming a cleanly calibrating criterion needs no rubric work at all
Why it failsCriteria with crisp, mechanical instructions calibrated cleanly in the source, but the source does not state a general rule about which criteria will need revision.
Do this insteadMeasure every criterion, even ones expected to be simple, before routing it.
Common mistake Believing a numeric cutoff is given in the source
Practice Deciding Routes From Agreement Results
A criterion shows agreement of ninety-four percent on its first measurement, but its instructions describe a hard-fail condition that a reviewer could read in two different ways. Using what the source says about C1, decide whether the judge should be trusted on this criterion right away, and explain what evidence you would still want before routing it to automatic grading.
Hints
- Compare this case to C1, which reached ninety-four percent only after two rubric revisions.
- Consider whether a result from one measurement, on one set of contracts, is enough to make a routing decision.
- Think about what the two readings of the instruction imply for whether the judge and the human labels are measuring the same thing.
Key Takeaways
- LLM-judge calibration checks a judge's grades against a set of handlabeled contracts so that trust rests on measured agreement rather than assumption.
- Agreement is measured criterion by criterion against human grades, and the source trusted the judge on C1 at ninety-four percent while keeping C2 manual at seventy-one percent.
- Calibration is iterative: the judge took six iterations to reach useful range, and C2 reached eighty-six percent only after a third pass once the rubric stabilized.
- Criteria with crisp, mechanical instructions, such as C3 and C4, calibrated cleanly on the first attempt, but the source offers this as an observed pattern rather than a general rule.
- A criterion goes to automatic grading only when its measured agreement is high enough for the team; otherwise it stays manual while the rubric is revised and re-measured.