L5 / IC4 equivalent (lab RS) · PhD, 0–5 years after it

AI Research Scientist interview prep, what to expect

A Research Scientist loop at a frontier lab is built around your own work. The centre is a research talk of 45 to 60 minutes on one project, then rounds that probe the choices in it: a paper discussion, an open-problem session where you frame the experiments, and a coding round whose bar sits below the engineer loop and still removes strong candidates.

Anthropic adds a 45-minute safety round and a 90-minute CodeSignal screen. Google DeepMind adds an oral quiz on undergraduate mathematics that candidates years out of academia often fail. OpenAI sends a paper two or three days before the onsite and expects a critique. The bar is a first-author record at top venues and the ability to defend every design decision under pressure. Four to eight weeks, plus team matching.

The loop

7 rounds

9 sample questions in this guide

Calendar time

4–8 weeks, plus 2–4 for team matching

Recruiter screen to offer

Median base · US labs

$230–415k

Levels.fyi, read 11 September 2026.

Make it yours

This is the general Research Scientist bar. Your interviews are at a specific company, with its own questions.

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2026 update

A few things have changed in 2026. AI is now allowed in coding rounds at Canva and Meta, detection has improved at companies that still ban it, pay has split at staff+, and the post-onsite wait got longer. Read what changed in 2026 →

01

What you'll be expected to do

What they're grading
  • Own a research direction: pick the problem, design the experiments, and decide when a result is real
  • Publish first-author work at NeurIPS, ICML, ICLR or the equivalent venue for your field
  • Implement your own ideas in PyTorch or JAX and run them at the scale the lab works at
  • Read the field closely and bring what changes the lab's plan, in writing and in reading groups
  • Reason about the safety, evaluation and failure modes of the models you train as well as their benchmarks
  • Work with research engineers on infrastructure and with product teams when a result is ready to ship
02

What does the interview loop look like?

7 rounds · 4–8 weeks, plus 2–4 for team matching

Most companies follow a similar pattern for Research Scientist interviews. Total calendar time is 4–8 weeks, plus 2–4 for team matching from recruiter screen to offer.

01
Recruiter and hiring manager screens
30–45 min each

Research background, publication record, which team and problem area you want, and why this lab. Anthropic's recruiter screen already probes your view of safety research

What they're scoring

  • A coherent research story rather than a list of papers
  • A reason for this lab that names its work
02
Coding screen
60 min CoderPad, or a 90-min CodeSignal at Anthropic

Practical problems rather than puzzles: an LRU cache, a rate limiter, or a multi-part NumPy and PyTorch exercise. Anthropic's CodeSignal runs four progressive levels and grades on full correctness; many strong researchers fail here

What they're scoring

  • Working code at speed, with tests
  • Fluency in NumPy and PyTorch without looking things up
03
Research talk
45–60 min, slides, questions throughout

One project of yours: motivation, the gap in prior work, your design decisions, results with ablations and negative results, limitations. Interviewers interrupt on the decisions and press on the weaknesses

What they're scoring

  • Every choice defended with the alternatives you rejected
  • Limitations named before the interviewer finds them
04
Paper discussion
60 min, sometimes 2–3 rounds at DeepMind

At OpenAI a paper arrives two or three days before the onsite: idea, methodology, findings, limitations, and how it connects to your own work. At DeepMind the paper can be one you authored or one you studied deeply, with different interviewers testing different subdomains

What they're scoring

  • Critique that goes past the abstract to the experimental design
  • What you would run next, and why
05
ML coding, implementation and debugging
45–60 min

Implement an algorithm from scratch without references (k-means, an LSTM cell, an attention variant), or fix a neural network that runs but does not learn: broadcasting errors, softmax on the wrong dimension, the wrong inputs to a loss

What they're scoring

  • Bugs found by reasoning about tensor shapes rather than by trial
  • Clean code under time pressure
06
Fundamentals quiz and research judgment
45–60 min, oral at DeepMind

DeepMind asks undergraduate-level questions out loud: the rank of a matrix, L1 versus L2 regularisation, the gradient of logistic regression. Most labs also run an open-problem session where you propose experiments, metrics, a theoretical angle and a way to falsify your own hypothesis

What they're scoring

  • Definitions and derivations from memory
  • A plan that could fail, and knowing how you would tell
07
Safety, mission and behavioural
45 min at Anthropic; two 30–45 min rounds at OpenAI; a team-lead round at DeepMind

Anthropic's safety round is conversational: the strongest arguments against Constitutional AI, what you do when a model behaves differently in evaluation than in deployment. Elsewhere mission and collaboration sit inside behavioural rounds

What they're scoring

  • Safety treated as a research problem you have thought about
  • Disagreements with collaborators told with the outcome
Bar chart of interview rounds by tech role for 2026, showing where Research Scientist sits among comparable roles.
Research Scientist runs 7 rounds. See where every role lands in the 2026 Tech Interview Report.
03

Sample questions you should be ready for

9 of the ones that decide it

Representative of what companies ask at this level. Every question here can be practised out loud, which is the fastest way to find out whether your answer holds up under follow-ups. Calibrd adds voice practice with coaching on every answer, and a full voice mock interview: a live round with an AI interviewer who has read the role and your CV, then an honest debrief.

Technical / coding
  • 01Here is a training script that runs without errors but the loss never falls below its starting value. Find the bug and tell me how you found it.
  • 02Implement scaled dot-product attention in NumPy, then tell me what changes when you make it multi-head, and what the memory cost is at a sequence length of 32k.
  • 03What is the rank of this matrix, and why does it matter for the low-rank adapter you would train on top of a frozen model?

Practise these out loud →

System design
  • 04We think our model's performance on long-context tasks is limited by the position encoding. Design the experiments that would confirm or refute that in two weeks of compute.
  • 05You have a paper claiming a 4-point gain on a benchmark. Before we adopt the method, what would you run to decide whether the gain is real?
  • 06Propose an evaluation for whether a model behaves differently when it can tell it is being tested. What would count as evidence either way?

Practise these out loud →

Behavioural · STAR method
  • 07Walk me through the research decision in your talk you are least sure was right, and what you would do differently now.
  • 08Tell me about a result that did not replicate. What did you do, and who did you tell?
  • 09Why this lab, and which problem here would you want to own in your first year?

Practise these out loud →

These are the general ones. Paste a real posting and Calibrd predicts the questions that company asks for that exact role, then interviews you on them.

Predict my questions →
04

Compensation benchmark

US majors · USD · median

Typical pay for Research Scientist at major US tech companies, headline numbers in USD. Typical pay in London, Berlin and Singapore is meaningfully lower, and equity varies a lot by company stage.

Base salary$230–415k (US labs)
Equity · annual vest$150k–970k/yr
Bonus0–10%; most labs pay none

Levels.fyi, read 11 September 2026. OpenAI Research Scientist median $800K: L4 $766K ($293K base, $473K stock), L5 $1.38M ($415K base, $968K stock), no bonus. Google Research Scientist median $427K: L5 $511K ($230K base, $256K stock, $25K bonus), L6 $606K. Anthropic Research Scientist median $425K with a top reported package above $892K; the page had too few submissions to show a level split. Stock is the larger half at every lab and is private-company paper at OpenAI and Anthropic.

05

How to prep

6 tactical tips

Lead behavioural answers with the STAR method: Situation, Task, Action, Result. The tips below build on that structure for this specific role.

  1. 01Build the research talk first and rehearse it against interruption. Twenty-five minutes of slides on one project: motivation, gap, design decisions, ablations, negative results, limitations. Have a colleague stop you every two minutes with "why not the other way"
  2. 02Relearn the undergraduate mathematics out loud. Rank, eigenvalues, the gradient of logistic regression, KL divergence, why L1 gives sparsity. DeepMind asks these verbally and rejects researchers who cannot answer from memory
  3. 03Write NumPy and PyTorch from scratch on a timer: attention, an LSTM cell, k-means, a training loop. Then practise debugging a network that runs but does not learn, because that round exists and nobody prepares for it
  4. 04Read five to ten recent papers in your area deeply enough to critique the experimental design, and prepare to receive one paper two or three days before an onsite
  5. 05Prepare a safety answer even if your work is not safety. Anthropic runs a 45-minute round on it, and a brilliant candidate who waves it away is the rejection every lab describes
  6. 06Read Hamming's 'The Art of Doing Science and Engineering' for the research-taste conversation: which problems are worth working on, and why you chose yours
06

Where do Research Scientist candidates fail?

Spot it in a mock first

A few common mistakes that get Research Scientist candidates rejected even when they are otherwise strong. Worth catching in a mock interview before they show up in a real one.

Failure 01

Presenting the research talk as a results tour and becoming defensive when an interviewer presses on a known weakness.

Why it fails

The talk is graded on whether you can defend your research choices under pressure while staying open to alternatives. Every lab describes the same rejection: a strong record, and a candidate who argued with the limitation instead of owning it. The interviewer already knows the weakness; the round tests what you do when it is named.

The losing answer

We tried that and it did not work as well, so this is the right approach for the setting.

The winning answer

That is the weakest part. We compared against the linear baseline only at one scale; at 7B it might close the gap, and the two-week experiment that would tell us is a sweep over model size with the same data. If it closes, the contribution is the data pipeline rather than the architecture.

Fix

Put the limitations on their own slide before anyone asks, and for each design decision name the alternative you rejected and the evidence that decided it. When pressed, agree with what is true, then say what you would run to settle it.

Practise thisWhich decision in your talk are you least sure was right, and what would change your mind?
Failure 02

Treating the coding rounds as a formality because the role is research.

Why it fails

OpenAI describes its scientists as people who turn ideas into working code quickly, Anthropic's CodeSignal screen grades on full correctness across four levels, and DeepMind runs an implementation round and a debugging round. The bar is below the engineer loop, and it still removes many strong researchers.

The losing answer

I would normally look up the exact broadcasting rules, but roughly the batch dimension goes first.

The winning answer

Logits are batch by vocab, targets are batch, so the loss wants class indices, and the bug is that we passed one-hot targets. Fixing that, and the softmax in the model is applied on dimension 0, which is the batch, so it normalises across examples; it should be the last dimension.

Fix

Two weeks of timed practice: practical problems (a cache, a rate limiter), from-scratch implementations of attention and a training loop, and debugging a script that runs but does not learn. Speak your tensor shapes out loud while you code.

Practise thisThis model trains but the loss plateaus at the value of a uniform prediction. Find the bug.
Failure 03

Answering the fundamentals quiz with intuition where a definition was asked, years after last needing one.

Why it fails

DeepMind's oral quiz asks for formal definitions and derivations at undergraduate level, and its interviewers say candidates who have been in industry for years forget them and fail on that alone. The round is a filter for unaided reasoning, and no AI assistance is allowed.

The losing answer

L1 tends to push some weights to zero, L2 keeps them small; L1 is more of a feature selector.

The winning answer

L1 adds lambda times the sum of absolute weights, whose subgradient is constant in magnitude, so the penalty keeps pushing small weights to exactly zero; L2 adds lambda times the squared norm, whose gradient shrinks with the weight, so weights approach zero without reaching it. Geometrically the L1 ball has corners on the axes, which is where the loss contour first touches it.

Fix

Spend a week on Mathematics for Machine Learning and derive by hand: gradients for logistic regression and a two-layer network, the bias-variance decomposition, KL between two Gaussians, the rank-nullity theorem. Say the definition first, then the intuition.

Practise thisExplain the difference between L1 and L2 regularisation, with the gradient of each.
Failure 04

Giving a generic answer to why this lab, or dismissing the safety round as a formality.

Why it fails

Labs select for people who want their specific problems. Anthropic's safety round is described by its own candidates as the one that decides, and the lab names technical brilliance combined with a dismissive attitude to safety as the error it most wants to avoid. OpenAI and DeepMind fold the same question into behavioural and team-lead rounds.

The losing answer

I want to work on the frontier and this is where the best models are being built.

The winning answer

Your interpretability team's work on feature attribution stops at the residual stream, and my thesis method on causal probing gives a way to test whether those features drive behaviour rather than correlate with it. The first experiment I would propose is an ablation on the features your paper flagged as safety-relevant.

Fix

Name a paper or a team at the lab and the open question in it you would take on. For safety, prepare one considered position on an actual method, such as the strongest arguments against Constitutional AI, and what you would do if a model behaved differently in evaluation than in deployment.

Practise thisWhy this lab, and which problem here would you want to own?
07

Recommended resources

No affiliate links

Books, courses, and tools that come up most often in Research Scientist prep.

08

Common scenarios

Situations that come up a lot
My PhD is in computer vision and the labs are hiring for language models. Do I interview as a research scientist, and how do I frame the talk?

You interview, and the talk is where the field gap closes or does not. Labs grade the talk on research judgment: motivation, the gap, the design decisions, the ablations you ran and the ones you should have. Those transfer whole from vision to language. What does not transfer is the paper discussion and the open-problem round, where the interviewer will hand you a language-model question and watch you reason. Spend the weeks before the onsite reading five to ten recent LLM papers deeply enough to critique the experimental design, and pick your talk project for the decisions in it rather than the modality. In the why-this-lab answer, name a language problem at the lab that your method speaks to, such as a probing or evaluation technique, and propose the first experiment. A vision researcher who arrives with one concrete LLM experiment in hand is judged as a researcher; one who arrives with a vision talk and no bridge is judged as a transfer candidate.

I am an ML engineer with six years in industry and no PhD. Can I get a research scientist offer at a frontier lab, or should I apply as a research engineer?

Apply as a research engineer unless you have first-author papers at top venues. DeepMind's research scientist track requires a doctorate in practice, and every lab's talk and paper rounds assume a publication record to interrogate; without one there is nothing for the loop to grade. The research engineer loop at the same labs is where your profile wins: the coding bar is higher, the implementation and debugging rounds are the centre, and the research rounds ask whether you can run someone else's idea well rather than originate it. Pay at the labs is close between the two titles at the same level. If you want the scientist title later, the route that works is publishing from inside: research engineers at these labs co-author, and a first-author paper from a lab team is the credential the scientist loop wants. Prepare for the engineer loop with the research engineer guide, and keep the talk-style project narrative from this one, because the same interviewers ask both.

I finished my PhD five years ago and have been in industry since. How do I prepare for the DeepMind fundamentals quiz without going back to university?

Two weeks of deliberate derivation, out loud. The quiz is oral, undergraduate level, and unaided, and DeepMind's own interviewers say candidates out of academia for years fail it on formal definitions they once knew. Work through Mathematics for Machine Learning with a notebook and a timer: the rank-nullity theorem, eigendecomposition and why it matters for PCA, the gradient of logistic regression and of a two-layer network by hand, the bias-variance decomposition, KL divergence between two Gaussians, why L1 gives sparsity with the subgradient argument. For each, practise saying the definition first and the intuition second, because the round rewards the definition and then asks for the picture. Pair it with the debugging round, which also tests what you retained rather than what you can look up: a script that runs but does not learn, and the three or four bugs that cause that. Five years of industry gives you the research talk and the judgment rounds; the quiz is the one place experience counts against you.

My research has nothing to do with safety. How do I handle Anthropic's safety round, and does OpenAI or DeepMind have one?

Anthropic's is a 45-minute conversational round, and candidates describe it as the one that decides. It is not a test of a safety publication record; it tests whether you have thought about the problem as a researcher. Prepare two considered positions: the strongest arguments against Constitutional AI as a method, with what evidence would settle them, and what you would do if a model behaved differently during evaluation than in deployment. Connect one to your own work, for instance how your evaluation method would detect that gap. The failure the lab names is a brilliant candidate who treats the question as a formality. OpenAI has no dedicated round and folds alignment into the research and behavioural discussions; DeepMind puts mission and values into the final round with team leads. The same two prepared positions serve all three, and at OpenAI and DeepMind the question tends to arrive as "how would this affect what you would build" rather than as a separate hour.

09

Frequently asked questions

Is this guide for research scientist roles only at the frontier labs, or also at applied labs and big tech research groups?

The loop described here is the frontier-lab shape (OpenAI, Anthropic, Google DeepMind), with the differences between them named per round. Meta FAIR, Microsoft Research and the applied labs run the same spine of a research talk, a paper deep dive and coding, with Meta adding two LeetCode-style problems per 45-minute coding session and an ML system design round, and Microsoft Research leaning further toward publication record and the talk. The pay figures are for the three frontier labs; big-tech research groups sit on their company's engineering ladder.

How long should I prep before my Research Scientist onsite?

The process takes four to eight weeks, and team matching can add a month. Give the research talk the first two weeks of prep and rehearse it against interruption; give the fundamentals and the from-scratch coding the next two, because those are the rounds that remove strong researchers.

What's the most common mistake candidates make at the Research Scientist bar?

Preparing the talk and nothing else. The talk is where a strong record shows, and the rejections come from the rounds around it: a CodeSignal screen failed on correctness, an oral quiz on undergraduate mathematics answered with intuition, a safety question treated as a formality, and a known limitation defended instead of owned.

What if my interview process is different from what's listed?

Most variation is at the edges. Major tech companies (FAANG, scale-ups, mid-size SaaS) follow processes within 1–2 rounds of what's described. Smaller startups often run fewer rounds (3–4) but the bar at each round is similar; less-tech-mature companies sometimes skip system design or behavioural rounds entirely. Read the posting and ask the recruiter on the screening call; they'll tell you what's coming.

How does this guide compare to running a free scan?

This guide covers the general bar at L5 / IC4 equivalent (lab RS). The free scan reads your specific job description and returns predicted questions for that exact role + company, a pay benchmark matched to the role and, with your CV, a read on your experience gaps and an ATS resume check, emailed as a PDF.

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Walk into your Research Scientist interview ready.

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AI Research Scientist Interview Prep — Calibrd