What each one actually measures
A work sample is a short, realistic task that mirrors the job — replying to a difficult customer, running a discovery role-play, choosing the strongest of several drafted emails, reconciling data. It measures the work itself: can this person do a representative slice of what the role requires, scored against a standard?
An interview measures something different and narrower than we usually admit. A well-structured interview is good at motivation, context, communication, and how someone reasons out loud about past situations. An unstructured interview, by contrast, mostly measures how comfortably a person talks about work under low stakes — which is why it rewards confidence, rapport, and polish, and why it is so easy to pass without being able to do the job.
The core distinction: a work sample shows you behaviour; an interview shows you a conversation about behaviour. Both can be useful — but only if you ask each to do the job it is actually good at.
Predictive validity, framed honestly
It is tempting to cite a precise number for how much better one method predicts performance, and the assessment industry does this freely. We will not invent one. The honest, defensible claim is directional and well-supported by decades of hiring research: sampling the actual work tends to predict on-the-job performance more reliably than an unstructured interview, and structure improves any method.
The reasoning is intuitive. The best evidence that someone can do a task is watching them do a representative version of it, under conditions close enough to real work to be meaningful. An unstructured interview is several steps removed — it asks the candidate to describe or claim the work rather than perform it — so it leaves more room for confidence and rapport to stand in for competence.
Two caveats keep this honest. A badly built work sample — ambiguous, unrepresentative, or scored on gut feel — predicts poorly too; the advantage comes from realism plus a rubric, not from the format alone. And a well-structured interview (same questions, same criteria, scored against a guide) is far more predictive than a free-flowing chat. The comparison that matters is structured vs. unstructured, and work-sample vs. talk-about-work — not a single magic coefficient.
Bias and fairness
Unstructured interviews are where much hiring bias lives: the halo effect from one strong answer, similarity bias toward candidates who remind us of ourselves, and inconsistent questions that make candidates genuinely incomparable. Because the interviewer scores on impression, these effects are hard to see and easy to rationalise as 'fit'.
A work sample scored against a rubric narrows that room. Everyone does the same task and is measured against the same explicit descriptors, so 'I liked them' has to become 'they acknowledged the customer, stayed accurate, and gave a clear next step'. That is more comparable and more defensible — though not automatically fair: a work sample can still disadvantage people if it is unrepresentative, inaccessible, or too long to fit around real life. Fairness comes from a representative task, a rubric written in advance, reasonable timing, accommodations, and proportional integrity — never a surveillance dragnet, and never a hidden score that follows a candidate across employers.
- Score work samples against a rubric written before review, with concrete descriptors per level.
- Keep the task representative, accessible, and proportional in length.
- Structure interviews too: same questions, same criteria, scored against a guide.
- Keep integrity checks proportional to the stakes; no cross-employer reputation scores.
When to use which
This is not a contest with one winner. Use each method for what it does best, and let the work sample carry the weight of the decision because it is the part that most resembles the role.
- Use a light work sample or situational-judgement exercise early, to screen on job-relevant behaviour instead of résumé polish.
- Use a fuller work sample for shortlisted candidates, to see the actual work scored against a rubric.
- Use a structured interview to add what the sample cannot show: motivation, context, career direction, and team considerations.
- Avoid letting an unstructured interview override work-sample evidence — that reintroduces exactly the bias the sample removed.
- Keep the whole process proportional; more rounds are not more signal.
How SkillCort combines them into evidence
The goal is not to pick a method but to assemble evidence. In practice that means a role blueprint that names the competencies, a realistic work sample scored against a shared rubric by more than one evaluator, and a structured interview whose notes are captured against the same competencies rather than left as loose impressions. Each method contributes to the same picture instead of competing for the final say.
AI supports this without deciding it: it can summarise a long response or a role-play, map an answer to the competencies it touched, draft consistent first-pass notes, and flag a possible integrity signal for a human to review. The line that must not move is who decides — AI does not select, reject, rank, or carry a hidden score about a candidate across employers. A human weighs the evidence and makes the call.
Assembled together, the task, the responses, the rubric scores, the structured interview notes, the reviewers, and the reasoning form a decision file: comparable across candidates, explainable to stakeholders, and defensible after the fact. That is what turns 'work sample vs. interview' from an argument into a single body of evidence.
Common mistakes to avoid
Teams tend to get the work-sample/interview balance wrong in predictable ways.
- Treating the interview as the assessment and the work sample as a formality.
- Running an unstructured interview and calling the impression it produces 'fit'.
- Building a work sample that is unrepresentative, ambiguous, or scored on gut feel.
- Letting one strong interview overrule weaker work-sample evidence.
- Citing invented validity numbers to justify a choice, instead of reasoning from realism and structure.
- Handing the decision to a score or a model rather than a human reviewing the evidence.
Key takeaways
- A work sample shows behaviour; an interview shows a conversation about behaviour — ask each to do what it is good at.
- Honestly framed, sampling the actual work tends to predict performance better than an unstructured interview; structure improves any method.
- Rubric-scored work samples narrow bias and are more comparable, but fairness needs a representative, accessible, proportional task.
- Use a light sample early, a fuller sample for shortlists, and a structured interview for what the sample cannot show.
- SkillCort combines both into a decision file — AI supports evaluation, a human decides, no cross-employer scores.