The first engineering panel I helped assemble in Singapore was four good engineers and no agreed definition of what we were looking for. Everyone interviewed well by their own standards. Two candidates were rejected by one person each for reasons the other three disagreed with, one offer went out because the most senior voice spoke first in the debrief, and the one hire we all felt confident about was the one whose university everyone recognised. None of that was anybody’s fault. It is simply what an uncalibrated panel does. Here is the method I would use instead, in order, and the parts you can skip if you are small.
Step 1: Define the Signals Before You Touch the Questions
The usual sequence is backwards. A role opens, four available people are put on the loop, and each is asked to form a view. The predictable result is that each interviewer measures what they personally value, and the hiring decision becomes an argument about which of four private standards should win.
Start by naming four or five signals the role genuinely requires, written in the language of the job rather than of a competency framework. For a mid-level backend role that might be: can they debug a system they did not write, can they scope ambiguous work into something shippable, can they review code so that a junior gets better, can they operate what they ship. That is the whole document and it should fit on one page. If you cannot write it, the panel is not the problem and no amount of calibration will rescue the loop.
Step 2: Write Behavioural Anchors, Not a One-to-Five Rating
A bare numeric rating records how generous the interviewer was feeling. Two interviewers who both write “4” have very often seen different things, and nothing in your records will ever reveal that.
For each signal, write what weak, adequate and strong look like in observable behaviour. The test of a usable anchor: two interviewers reading the same transcript would pick the same level. So instead of “communication: 3/5”, the adequate anchor reads something like “described the trade-off when asked”, and the strong anchor reads “raised the trade-off unprompted and named what they would monitor after shipping”. That is a sentence an interviewer can check their notes against.
This is the structured interviewing principle rather than an invention of ours. Google’s re:Work guide on structured interviewing makes the same two recommendations: ask every candidate the same questions, and score the answers against a consistent rubric. The reason it is worth the effort is covered in the FAQ below, and it is an evidence question rather than a taste question.
đź’ˇ Our Expert Take
Write the anchors with the panel in the room, not alone the night before. Half the value of an anchored scorecard is the argument you have while writing it, because that argument is where four people discover they had different definitions of senior. Handing a finished rubric to a panel that never debated it produces compliance without calibration. (William)
Step 3: Calibrate on Candidates You Have Already Decided
This is the step that does the actual work, and the one that gets cut for time.
Take three or four candidates you interviewed in the past and whose outcome you already know. Strip the identifying details. Give every interviewer the same material and have them score independently against the new scorecard. Then put the scores side by side.
The agreements tell you the scorecard works. The disagreements are your entire training curriculum, and they surface three things no handbook will:
- Which anchors are ambiguous. If two careful people read the same evidence into different levels, the anchor is badly written. Fix the wording, not the people.
- Who is systematically harsher or softer. This is not a character flaw and it is easily corrected once visible. It is invisible forever without this exercise.
- Where the panel is measuring pedigree. Include one past candidate with an unimpressive background who performed well. The conversation that follows is more persuasive than any training on bias.
Two hours, once, with real candidates. It outperforms every interviewer handbook I have seen.
Step 4: One Signal Per Interviewer
Four interviewers each independently probing system design gives you one noisy reading of one signal and no reading of the other three. It also produces the complaint we hear most often from candidates in Singapore: being asked substantially the same question four times by four people who evidently had not spoken to each other. In a market this size, that experience travels.
Assign each interviewer a primary signal and the specific part of the loop that tests it. Just as importantly, tell them what they are not responsible for. An interviewer who knows they own code review quality and nothing else asks better questions for forty-five minutes than one who is vaguely responsible for the whole candidate.
| Interviewer | Owns | Does not assess |
|---|---|---|
| Engineer A | Debugging an unfamiliar system | Design breadth, communication polish |
| Engineer B | Scoping ambiguous work | Depth in a specific framework |
| Engineer C | Code review and mentoring | Architecture at scale |
| Engineering manager | Operating what they ship | Live coding ability |
If you are building the loop itself rather than only the panel, this step sits on top of the process we set out in structuring a technical interview process in Singapore, and the question design in writing technical interview questions.
Run it on your next loop
Send us the role and your current panel. We will tell you which signals are unmeasured and which are measured four times, and shortlist candidates against the corrected scorecard. Python developers
Get 3 Free Developer ProposalsStep 5: Written Scores Before the Debrief Opens
If a debrief begins with the most senior person in the room saying what they thought, every score that follows anchors to it. The panel has become one opinion with four witnesses, and the junior interviewer who saw the clearest evidence of a problem will not be the one to contradict a founder out loud.
So require a written score with evidence, submitted against the assigned signal, before the meeting opens. Then run the debrief only on the disagreements. The agreements need no discussion. The disagreements contain all of the information, and starting there usually turns a forty-minute meeting into fifteen.
One discipline makes this work: every score must cite evidence from the interview itself. “They came from a strong team” is not evidence from the conversation you just had, and requiring the citation is what quietly removes that whole class of reasoning without anyone having to be accused of bias.
Step 6: Measure the Panel, Not Only the Candidates
Every hiring process measures candidates. Almost none measure the instrument.
Three things are worth tracking, and none needs a tool:
- Agreement rate. How often do independent scores land in the same band? A panel that never disagrees is not calibrated, it is deferring, and that is as much a problem as constant disagreement.
- Solo rejections. How many candidates are rejected on one interviewer’s negative score alone. One person consistently doing this holds a veto rather than a seat.
- Rejected candidate review. Sample the people you declined and look at what they did next. If several went on to do the job you declined them for, at a comparable company, your bar is not high, it is misaimed.
That last one is uncomfortable and it is the only direct read you will ever get on your false negatives. Related, and cheaper to run alongside it, is the portfolio-based alternative to credential screening we describe in evaluating developer portfolios instead of degrees.
đź’ˇ Our Expert Take
If you only have the appetite for one measurement, choose solo rejections. It needs no statistics, it takes ten minutes against your last twenty candidates, and in every panel where we have run it the result surprised at least one person on it. Agreement rates need volume to mean anything. A single interviewer rejecting most of your pipeline alone does not. (William)
Step 7: Re-Calibrate on a Cadence
Calibration decays, quietly and in three ways. Anchors drift as the market moves and what counted as strong two years ago becomes ordinary. New interviewers arrive carrying their own standards from their last employer. And the role itself changes while the scorecard does not.
Re-run the step three session on a fixed cadence. Every two quarters is enough for most teams. Always do it before a new interviewer runs their first solo loop.
One caution about onboarding interviewers: shadowing an experienced colleague is useful, and it transmits that person’s drift along with their skill. Pair the shadowing with independent scoring of the same candidate, then compare. The new interviewer learns the scorecard rather than learning to imitate whoever trained them, which is the difference between a calibrated panel and a consistent one.
Three Mistakes That Undo the Whole Exercise
Writing the scorecard alone. The argument while writing it is half the value. A rubric handed to a panel that never debated it buys compliance, not calibration.
Calibrating once, at the start. A single session makes a panel consistent for about two quarters. Treat it as a recurring cost or it silently expires.
Letting the debrief start with a verdict. Everything upstream of the debrief, every anchor and every assigned signal, is cancelled out by one senior person speaking first.
FAQ: Interview Panel Calibration in Singapore
We are a ten-person team in Singapore. Is panel calibration overkill for us?
The full apparatus is overkill. The two steps that pay for themselves at any size are not. At ten people, the cost of a wrong senior hire is proportionally larger than it is at two hundred, and you have fewer places to absorb a mismatch, so the quality of the decision matters more rather than less. What you can safely drop is the measurement layer: with a handful of hires a year you will not have enough data for meaningful inter-rater statistics, and chasing them is a waste of time. What you should keep is the anchored scorecard and the rule that written scores are submitted before anyone speaks in the debrief. Those two cost about three hours to set up once and they remove the two largest sources of noise, which are interviewers measuring different things and a junior interviewer deferring to a founder. Start there and add the rest when your hiring volume justifies it.
How do we stop the panel from anchoring on where a candidate studied?
Pedigree anchoring is the single most common calibration failure we see in Singapore, and it has a local cause: the candidate pool spans local graduates, regional hires and experienced engineers from a dozen different education systems, so interviewers reach for the one signal that feels comparable across all of them. The university name feels like a common yardstick. It is not. Three things work in combination. First, write anchors that are purely behavioural, so there is no legitimate place on the scorecard to record a school or a former employer. Second, in the calibration session of step three, deliberately include a past candidate who had a weak-looking background and performed well, and one with a strong background who did not, then make the panel score them blind. The discussion afterwards is more persuasive than any instruction about bias. Third, in the debrief, require evidence from the interview itself for every score, which makes “they came from a good team” unusable as a justification because it is not evidence from the conversation you just had.
What if our best engineer is also our worst interviewer?
This is common and it is a role design problem rather than a performance problem. Strong engineers often interview badly for predictable reasons: they ask the question that interests them rather than the one on the scorecard, they assess whether they would enjoy working with the person, or they test for familiarity with their own stack and read unfamiliarity as weakness. None of that makes them a bad engineer and all of it produces unusable signal. The fix is to narrow their remit rather than to remove them. Give them the one signal where their depth is genuinely irreplaceable, usually a deep technical dimension, with a scorecard they did not write and anchors they agreed to in calibration. Take the broader judgement calls away from them. If the calibration data in step six shows them as a persistent solo rejector after two cycles of this, move them off the panel for senior roles and keep them for the technical deep dive. That is a reasonable outcome, not a demotion, and saying so plainly avoids a difficult conversation later.
Does structured interviewing really predict performance better, or is this just process?
It is one of the better-established findings in personnel research, and it is the reason this method is worth the hours rather than being administrative comfort. The classic reference point is the meta-analysis by Frank Schmidt and John Hunter published in Psychological Bulletin in 1998, which assessed the predictive validity of selection methods across decades of studies and found structured interviews substantially more predictive of job performance than unstructured ones. Google reached the same practical conclusion internally and published its approach through its re:Work guide on structured interviewing, which recommends asking every candidate the same questions and scoring answers against a consistent rubric. The mechanism is not mysterious: an unstructured interview mostly measures rapport and the interviewer’s memory of the most recent candidate, both of which vary enormously between interviewers and across a week. A structured one measures the same things in the same way, which is the only condition under which comparing two candidates means anything at all.
Run the two-hour session, then put it to work
Calibrate the panel on three past candidates this week. When you are ready to put the corrected scorecard against a real pipeline, tell us the role and we will shortlist against it.
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Sources: Google re:Work, guide on using structured interviewing, for the same-questions and consistent-rubric recommendations; Frank L. Schmidt and John E. Hunter, “The Validity and Utility of Selection Methods in Personnel Psychology”, Psychological Bulletin, 1998, for the comparative predictive validity of structured versus unstructured interviews. The seven-step sequence, the scorecard anchors, the one-signal-per-interviewer assignment and the panel measurements are our own practice from scoping engineering teams for Singapore employers.