NYU Langone Health · Data Scientist
Updated · 2026-09-22

NYU Langone Health Data Scientist
Interview Questions & Guide 2026

THE 60-SECOND BRIEF

At NYU Langone Health, a Data Scientist transforms complex clinical and research data into actionable insights that improve patient outcomes, accelerate discovery, and inform strategic decisions. You will build models that guide clinicians, develop methods that elevate the standard of research, and design analytics pipelines trusted across our health system and schools of medicine. Your work will touch priorities ranging from clinical decision support and population health to statistical genetics, environmental epidemiology, and operational efficiency.

Ask early whether the loop includes an asynchronous take-home or a timed live case, because the two are graded on different things. A take-home is read as an artifact: the question you decided to answer, what you did about missing or malformed records, and a conclusion stated plainly enough for someone to act on. A reviewer who cannot rerun your notebook discounts the result whatever score is printed in it. Hold to the stated time box and write down what you would have done with more of it, since the follow-up round is usually a live defence of the same work.

PracHub has no confirmed round sequence for NYU Langone Health. Treat the sections below as preparation areas and confirm the format with your recruiter.

Correct for claims runout before reporting recent monthsSeparate censoring from events in time-to-event modelsBuild member-month denominators from overlapping coverage spans

29 min read

Browse Data Scientist questions

See the practice prompts

12Practice promptsAcross five skill areas
3With worked solutionsIncluded in the practice prompts

At NYU Langone Health, a Data Scientist transforms complex clinical and research data into actionable insights that improve patient outcomes, accelerate discovery, and inform strategic decisions. You will build models that guide clinicians, develop methods that elevate the standard of research, and design analytics pipelines trusted across our health system and schools of medicine. Your work will touch priorities ranging from clinical decision support and population health to statistical genetics, environmental epidemiology, and operational efficiency.

You will collaborate with world-class investigators and clinicians, including teams such as the Center for Human Genetics and Genomics (e.g., polygenic risk prediction and genetic architecture of complex traits) and divisions like Environmental Pediatrics (e.g., longitudinal cohort analyses, biomonitoring, and public health surveillance). This role is critical because health data is high-stakes, high-dimensional, and heterogeneous (EHR, imaging, genomics, registries). The ability to make rigorous, ethical, and interpretable inferences is not just a technical requirement—it is a responsibility to our patients, our communities, and our scientific mission.

Expect to operate at the intersection of statistical rigor, computational scale, and clinical relevance. You will be asked to design studies that stand up to peer review, build models that clinicians can trust, and produce results that translate into policy, practice, or new lines of inquiry. This is work that matters—scientifically and humanistically.

01

Preparation focus

editorial

No round sequence has been reported for this company, so work the categories below and confirm the format with your recruiter.

What to demonstrate

  • Breadth across SQL, experimentation and product reasoning
  • Ability to state assumptions before choosing a method

How to prepare

  • Drill the practice exercises below and time yourself
  • Prepare three quantified stories about decisions you drove
PracHub interview preparation framework ↗

PracHub editorial advice for the preparation topics above.

01

Treating clinical measurements as missing at random

A lab result, a vital sign, or a screening exists because someone ordered it, and ordering tracks suspicion of disease, visit frequency, and site workflow. Imputing the mean or dropping incomplete rows biases the population estimate and can flip the sign of an association, because the untested are systematically healthier or systematically disengaged. The presence indicator is often more predictive than the value, which is a warning sign rather than a feature win: a model that learns test ordering will not transfer to a site with different protocols.

02

Pre-post evaluation on a high-cost or high-risk cohort

Cohorts selected on an extreme value of the outcome regress toward the mean on their own. Members identified as the top 1 percent of spend in one year spend far less the next, whether or not anyone intervenes, because the selecting year captured both chronic severity and one-off events. A pre-post design on such a cohort will report savings every time. A concurrent comparison group selected by the same rule in the same period, or a regression discontinuity at the selection threshold, is the minimum credible design.

03

Ending an analysis without a recommendation or next step

Close with what you would do and what would change your mind, stated as a condition you can check later. If the evidence is genuinely inconclusive, recommend the specific next measurement and say what it costs in time or exposure.

04

Crediting a treatment for regression to the mean

Selecting a group because it is extreme (lowest-engagement users, accounts having their worst month, the bottom decile of a score) moves that group's expected next-period value back toward the average even under no treatment, by exactly as much as the selecting measure is imperfectly correlated with its own later value. Compare against units that met the same selection rule and went untreated, or use two pre-periods so the bounce-back is visible before the intervention starts. A pre-post number on a group chosen for being extreme measures the selection rule, not the treatment.

Choose a category, try a prompt, then open its approach, worked solution or follow-up when you need it.

9 technical prompts3 include a worked solution

Show how you would compute and interpret decision curves and net benef…

medium
machine learning and modelling

Show how you would compute and interpret decision curves and net benefit for a risk model.

Approach
  1. Say how the offline result would be validated online before it is trusted.
  2. Check what information would not exist at prediction time, and exclude it.
  3. Pick an evaluation metric that matches the cost of each error type, not a default.
Follow-up
  • How would you choose the decision threshold, and who owns that choice?
  • What would you monitor after launch to know the model is still valid?

How do you choose between logistic regression, gradient boosting, and …

medium
machine learning and modelling

How do you choose between logistic regression, gradient boosting, and a neural model for a binary clinical outcome? Discuss calibration and interpretability.

Approach
  1. Frame the prediction: the label, the moment of prediction, and the action it triggers.
  2. Say how the offline result would be validated online before it is trusted.
  3. Set a baseline first, so any model has something honest to beat.
Follow-up
  • Where could label leakage enter this setup?
  • How would you choose the decision threshold, and who owns that choice?

Walk through your approach to handling extreme class imbalance for det…

medium
machine learning and modelling

Walk through your approach to handling extreme class imbalance for detecting rare adverse events.

Approach
  1. Say how the offline result would be validated online before it is trusted.
  2. Frame the prediction: the label, the moment of prediction, and the action it triggers.
  3. Pick an evaluation metric that matches the cost of each error type, not a default.
Follow-up
  • Where could label leakage enter this setup?
  • What would you monitor after launch to know the model is still valid?

Simulate how ignoring clustering inflates the false positive rate

mediumWorked solution
simulationdesign effecttype i error

Simulate a provider-level comparison with no true effect. 40 providers, 60 members each, a continuous outcome with total variance 1 and intraclass correlation 0.02. Randomise providers 20 to 20, not members. Over 5,000 replications, report the share of replications where a two-sample t-test run on all 2,400 individual observations, ignoring provider, returns p below 0.05. Report the same share when the unit of analysis is the 40 provider means. Then state how the first number follows from the design effect 1 + (m - 1) x ICC.

Approach
  1. Decompose the variance explicitly rather than tuning it: provider variance = ICC = 0.02, residual variance = 1 - ICC = 0.98. Draw u_j once per provider and e_ij per member, so the outcome is u_j + e_ij and the correlation between two members of one provider is 0.02 by construction.
  2. Randomise at the provider level. That is the entire mechanism: the treatment indicator is constant within a provider, so in any single replicate the provider intercepts are confounded with the arm, and the naive test reads that confounding as signal.
  3. Vectorise over replications with a (reps, providers, members) array. 5,000 x 2,400 normals is trivial in numpy, and a Python loop is what tempts people to cut replications to 500 and report a number with Monte Carlo noise of plus or minus 0.017.
  4. Predict the answer before running it: design effect = 1 + (60 - 1) x 0.02 = 2.18, naive standard errors are too small by sqrt(2.18) = 1.476, so the rejection rate at nominal 0.05 is about 2 x (1 - Phi(1.96 / 1.476)) = 0.18. Agreement between prediction and simulation is what makes the result a demonstration rather than an anecdote.
  5. Run the provider-mean analysis as the control. Recovering 0.05 there proves the generator is correct and isolates the failure to the analysis unit.
Worked solution 30 min
  1. Draw u with shape (reps, 40) from N(0, sqrt(0.02)) and e with shape (reps, 40, 60) from N(0, sqrt(0.98)); y = u[:, :, None] + e.
  2. Assign providers 0-19 to one arm and 20-39 to the other; because there is no true effect, a fixed split is valid and removes one source of Monte Carlo noise.
  3. Naive test: flatten each arm to 1,200 observations and compute a two-sample t statistic per replication with vectorised means and pooled variance.
  4. Cluster test: average within provider to 40 values, then run the same two-sample t on 20 versus 20.
  5. Report both rejection shares and compare the naive one against 2 x (1 - Phi(1.96 / sqrt(2.18))).
EXPECTED RESULTThe naive individual-level test rejects in roughly 18 percent of replications, against a nominal 5 percent. Monte Carlo standard error at 5,000 replications is about 0.005, so anything in 0.17 to 0.19 is consistent. The provider-mean analysis rejects in about 5 percent, within roughly 0.003.
Follow-up
  • How many providers would you need for 80 percent power on a 0.2 SD difference with 60 members each and this ICC?
  • Cluster sizes are unequal in reality. The design effect approximation becomes 1 + ((1 + CV^2) x mbar - 1) x ICC. Which direction does that move your sample size and why?
  • The intervention cannot be withheld from any provider. Sketch a design that still yields a defensible estimate.

Instead of guessing where the week should go, day one measures it under a fixed rubric and allocates the remaining hours in proportion to the gaps. The method is deliberately rigid: the allocation is written down before any studying starts and is not renegotiated when a topic turns out to be unpleasant.

Small steps. Visible outcomes.0 / 7 completed
ONE WEEK · YOUR PACE

Prepare, practise & reflect

One practical outcome each day. Spend longer where you need it.

0 / 7 done
01Diagnostic, scored before you study anything
  • Sit a 100-minute timed diagnostic in four blocks: 30 minutes of SQL across three prompts, 25 minutes of short-answer statistics, 25 minutes on one modelling or case prompt, and 20 minutes delivering one behavioural story aloud.
  • Score each block from 0 to 3 on a fixed rubric where 3 is correct and fluent, 2 is correct but slow or prompted, 1 is partially correct, and 0 is stuck, grading the output rather than how the attempt felt.
  • Allocate the hours for days two to five roughly in proportion to 3 minus the score in each block, write the allocation down, and commit to not revising it midweek.

Deliverable: A scored rubric and a fixed hour allocation for the rest of the week.

Practice prompt ↗Practice prompt ↗Worked solution ↗
02Largest gap: find the boundary rather than the subject
  • Break the weakest area into five named sub-skills (for query work: grain control, window frames, date arithmetic, set logic with NULLs, and reading a query plan) and rate each one, so the rest of the week targets a sub-skill instead of a subject.
  • Solve three problems chosen to sit just above where the rating drops off, and for each write the first move you failed to make.
  • Re-solve one of them from memory four hours later, on paper, with nothing open.

Deliverable: A five-item sub-skill map with the two blocking sub-skills circled.

Practice prompt ↗Practice prompt ↗
03Largest gap: drill the blocking sub-skill
  • Do eight short repetitions of the same shape rather than eight different problems, so what you practise is the pattern and not the puzzle.
  • Write the rule you now hold in one sentence, then test it against a case built to break it: a ranking function over a column with ties, or a two-sample test on observations that are obviously dependent.
  • Have someone else read your one-sentence rule and find the precondition you left out.

Deliverable: One rule statement with its preconditions attached and one counterexample that would have caught the incomplete version.

Practice prompt ↗Practice prompt ↗
04Second gap, plus maintenance on your strongest area
  • Run the same sub-skill map and boundary protocol on the second-largest gap, compressed into half the day.
  • Spend 25 timed minutes on your strongest area to stop it decaying, choosing the hardest problem you can still finish rather than an easy warm-up.
  • Compare how the two areas fail: whether you lose time on recall, on setup, or on arithmetic, because the fix differs for each.

Deliverable: A second sub-skill map plus a one-line diagnosis of how each area fails you.

Practice prompt ↗Practice prompt ↗Worked solution ↗
05The gap that is not a skill
  • Record yourself answering one technical and one behavioural prompt, then count two things in the playback: how many seconds before your first clarifying question, and how many sentences you started without knowing where they ended.
  • Rewrite your three most-used stock phrases into shorter versions, and practise saying "I do not know, here is how I would find out" without softening it into a guess.
  • Deliver one answer again with a hard 90-second limit to force structure before detail.

Deliverable: Two recordings with a counted improvement in time-to-first-question.

Practice prompt ↗Practice prompt ↗
06Retest under day-one conditions
  • Sit the same 100-minute diagnostic structure with new prompts of comparable difficulty and score it on the identical rubric.
  • Compare block by block, and for any block that did not move, change the method rather than adding hours: a block stuck at 1 usually means the practice was too varied, not too short.
  • Write which single block you would still lose the offer on.

Deliverable: A second scored rubric placed next to the first, with one named remaining risk.

Practice prompt ↗
07Full loop under interview conditions
  • Run a 60-minute mock covering the two blocks that moved least, with an interviewer instructed to interrupt and change direction.
  • Write your recovery script for the moment you go blank: restate the question, state your assumption, name the first thing you would check.
  • Reduce the week to the rule statements you wrote, each with its preconditions attached, then say every one of them out loud without reading it and cut any you cannot state in a single sentence, since a rule you have to reconstruct mid-answer will not survive being interrupted.

Deliverable: A one-page card holding the recovery script and only the rules you could state from memory.

Practice prompt ↗Worked solution ↗

Expand any day for tasks and deliverables. Your progress is saved on this device.

Have two ready. In one, the data was on your side and you had to move someone who outranked you. In the other, the pushback was correct and you changed position. The second is the harder story and it lands better, because it shows you separate being right from being attached to an answer. Name the person's actual objection.

Describe a time when model performance degraded in production. How did…

medium
behavioural and stakeholder questions

Describe a time when model performance degraded in production. How did you diagnose and fix it?

Approach
  1. State the situation in two sentences and spend the rest on your reasoning.
  2. Name the disagreement or constraint, and how you resolved it with evidence.
  3. Pick a story where you drove the decision, not one where you observed it.
Follow-up
  • How did you know the outcome was caused by your change?
  • What did you decide not to do, and why?

Scope a one-line request for a readmission rate

easy
scopingmeasure specificationstakeholder communication

A clinical operations lead messages you: 'What is our readmission rate? The committee meets Friday.' You have encounter (encounter_id, admit_ts, discharge_ts, encounter_type, admission_type, discharge_disposition, drg_code, index_encounter_id) and member_enrollment coverage spans. Do not open a query editor yet. Deliverable: the three to five questions you send back, ranked by how much the answer moves the number; the default specification you will build if nobody replies by Wednesday; and the one line you will place under the figure so the committee does not read it against a published benchmark.

Approach
  1. Read the probe: this tests whether you convert ambiguity into a specification without either stalling or guessing silently. Both failure modes are common, and the silent guess is worse because nobody can see it.
  2. Rank your questions by leverage on the number rather than by curiosity. Whether the numerator is all-cause or unplanned, and whether the clock starts at discharge_ts, move the result far more than a tie-break rule on same-day returns.
  3. Ask about the comparison first. A number going to a committee will be compared to something, and whether that something is last quarter, another panel, or a national figure decides whether you owe them a raw rate, a risk-adjusted rate, or an observed-over-expected ratio.
  4. Commit to a default in writing so silence does not block you: unplanned acute inpatient readmission within 30 days of discharge_ts, index stays excluding planned admissions, acute-to-acute transfers, discharges against medical advice, and dispositions of expired or hospice, denominator of eligible index discharges, paid-through date stated.
  5. Write the caveat as a restriction on use rather than a hedge: name the one comparison the figure supports and the one it does not.
Follow-up
  • They reply that they want it 'the way the benchmark does it'. What do you ask next?
  • The committee wants it split by attending provider. What changes in the specification, and what do you refuse to show?
  • How does your answer change if the meeting is tomorrow rather than Friday?

Make an honest case for your own analytical impact

hard
impact attributioncounterfactualself-assessment

You are asked to account for a year of your work. Constraint: you may only use measures that existed before you knew the outcome, and you must include one project that moved nothing. The portfolio contains a measure specification that changed how a contract settles, a predictive model that shipped, a self-serve dashboard, and an evaluation that killed a proposed programme. Deliverable: how you attribute value to each, which of them you claim credit for and which you do not, and the one number you would accept being judged on next year.

Approach
  1. The probe is whether you can reason counterfactually about your own work, which is the same discipline this domain demands of you for programmes, applied where it is uncomfortable.
  2. State the counterfactual for each item: what would have happened without you. A measure specification that changed how a contract settles has a dollar counterfactual you can compute. A dashboard's counterfactual is analyst hours, which is real and small, and attaching a revenue number to it is where these accounts usually turn into fiction.
  3. Treat the killed programme as your strongest item and say why. Avoided spend is real value, it is attributable because the decision turned on your evaluation, and it is the one item nobody else will count on your behalf.
  4. Report the shipped model the way you would report anyone's model: calibration in the subgroups that matter, adoption by the people it was built for, and whether any decision changed. A model that is live but ignored has zero impact, and saying so is the credibility test in this answer.
  5. Name the failed project with its mechanism and its cost, then say what earlier signal you would watch to kill it sooner. Time to kill is a legitimate impact measure.
  6. Choose next year's number so that it can go down. A metric that only ratchets upward is not a commitment.
Follow-up
  • Two other people also claim the contract measure. How do you split it?
  • Your model is live and used, but the decisions it informs would have been the same without it. Is that impact?
  • What is the strongest argument that your year had less impact than you just described?
  • 01

    Describe a time when model performance degraded in production. How did you diagnose and fix it?

  • 02

    A clinical operations lead messages you: 'What is our readmission rate? The committee meets Friday.' You have encounter (encounter_id, admit_ts, discharge_ts, encounter_type, admission_type, discharge_disposition, drg_code, index_encounter_id) and member_enrollment coverage spans. Do not open a query editor yet. Deliverable: the three to five questions you send back, ranked by how much the answer moves the number; the default specification you will build if nobody replies by Wednesday; and the one line you will place under the figure so the committee does not read it against a published benchmark.

  • 03

    You are asked to account for a year of your work. Constraint: you may only use measures that existed before you knew the outcome, and you must include one project that moved nothing. The portfolio contains a measure specification that changed how a contract settles, a predictive model that shipped, a self-serve dashboard, and an evaluation that killed a proposed programme. Deliverable: how you attribute value to each, which of them you claim credit for and which you do not, and the one number you would accept being judged on next year.

PracHub interview preparation framework ↗
Is this an official NYU Langone Health interview guide?

No. It is PracHub's own research and practice material for the Data Scientist role at NYU Langone Health. Rounds and questions reflect what candidates have reported, not a process NYU Langone Health has published, and they change over time. Confirm the current format and scope with your recruiter.

PracHub interview research ↗
How difficult is the interview and how much time should I allocate to prepare?

Expect a rigorous but fair process. Most candidates benefit from 2–3 weeks of focused preparation across statistics/ML, study design, data manipulation, and a 5–8 minute project talk.

PracHub interview research ↗
What makes successful candidates stand out?

Clarity of thought, scientific rigor, and domain empathy. The strongest candidates explain assumptions, quantify uncertainty, protect privacy by design, and translate results into clinician- or investigator-friendly decisions.

PracHub interview research ↗
Will I need to present prior work?

Often yes. Prepare a concise talk tailored to a clinical/research audience, with backup slides for methods, diagnostics, and limitations.

PracHub interview research ↗
What is the typical timeline from first conversation to decision?

Timelines vary by team and study cadence, but strong alignment can move efficiently. Keep your availability flexible for multi-stakeholder panels.

PracHub interview research ↗
Sources & methodology 3 sources ↗

No official company page is cited. Rounds and questions come from candidate reports and PracHub editorial material; each source shows the date it was read.