Intermountain Health · Data Scientist
Updated · 2026-09-24

Intermountain Health Data Scientist
Interview Questions & Guide 2026

THE 60-SECOND BRIEF

As a Data Scientist at Intermountain Health, you operate at the critical intersection of advanced analytics and patient care. Your work is not merely about building models; it is about leveraging massive, complex healthcare datasets to drive clinical decision-making, optimize operational efficiencies, and ultimately improve health outcomes for the communities Intermountain Health serves. You will be tasked with translating ambiguous clinical questions into rigorous quantitative frameworks that have tangible impacts on patient lives.

Seniority shifts the scope more than the words in the title do. Earlier-career loops mostly check that you execute a well-posed analysis correctly; senior loops check that you can decide which question is worth answering and defend what you chose not to do.

Intermountain Health candidates report 5 rounds · ≈ 4-6 weeks. The stages below are what candidates describe, not a published process.

Risk-adjust outcomes before comparing providers or panelsBuild member-month denominators from overlapping coverage spansSeparate censoring from events in time-to-event models

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See the practice prompts

11Practice promptsAcross five skill areas
3With worked solutionsIncluded in the practice prompts

As a Data Scientist at Intermountain Health, you operate at the critical intersection of advanced analytics and patient care. Your work is not merely about building models; it is about leveraging massive, complex healthcare datasets to drive clinical decision-making, optimize operational efficiencies, and ultimately improve health outcomes for the communities Intermountain Health serves. You will be tasked with translating ambiguous clinical questions into rigorous quantitative frameworks that have tangible impacts on patient lives.

The role demands a high degree of technical proficiency combined with the ability to communicate complex findings to non-technical stakeholders, including clinicians and hospital administrators. You will be working within an environment where data integrity and ethical considerations are paramount. Whether you are developing predictive models for patient risk or analyzing large-scale healthcare trends, your contributions are central to the mission of Intermountain Health to provide high-value, high-quality care.

Candidates should emphasize their ability to handle real-world, "messy" data, as clinical datasets often require significant cleaning and domain-specific context before modeling can begin.

01

Initial Recruiter Screen

reported

Data Scientist covers at least four different jobs: experimentation, product analytics, causal work on observational data, and applied modelling that ships into a system. A screening call is the cheapest place to find out which of them is being hired for, and doing that diagnosis openly reads as senior rather than fussy. Ask what the last few pieces of work on the team actually were, and roughly how a week splits between querying, modelling and stakeholder time. Then say which parts of that you have done and which you have not. Claiming the whole range is the fastest way to be caught one round later.

What to demonstrate

  • Whether you can distinguish the flavours of the role and locate your own experience inside one of them honestly
  • Whether you name what you have not done instead of stretching to cover every line of the posting
  • Whether your hard constraints (notice period, location, work authorisation, level) surface now rather than at offer stage

How to prepare

  • Map the last two years of your time into rough percentages across query writing, experiment design, modelling and stakeholder work, so a question about scope has a real answer
  • Mark every responsibility in the posting as done, adjacent or new, and prepare one sentence for each adjacent item naming the closest thing you have actually built
  • Decide which logistics are non-negotiable before the call so you can state them in one sentence rather than negotiating live
PracHub interview research ↗
02

Technical Deep-Dive

reported

Much of what gets scored here happens out loud while you type. Nobody can see your reasoning inside a half-written query, so five silent minutes read as being stuck even when they are not. State the plan in plain language first: which tables, what grain you are aggregating to, and the one filter that defines the population. Then write it. The narration doubles as insurance, because a wrong plan gets caught early and cheaply while a wrong query gets caught at the end with no time left to redo it. A timed statistics section, where one exists, is a separate test with its own clock.

What to demonstrate

  • Whether the query you write matches the plan you just described
  • What you do with a hint, meaning whether the correction gets absorbed or the first approach gets defended
  • Whether you can debug your own wrong output by reading the result set and naming which part of the query produced the anomaly

How to prepare

  • Solve three problems while screen-sharing into a recording, then watch it back and mark every stretch longer than thirty seconds where you said nothing
  • Practise compressing the plan into one sentence before typing, then check afterwards whether the finished query actually matched it
  • Time yourself on statistics questions that carry a business reading, such as what a confidence interval does and does not claim, rather than re-reading notes without a clock
PracHub interview research ↗
03

Conceptual Discussions

reported

An added round often puts you in front of someone outside the core hiring team: a partner engineer, a product owner, a domain expert, sometimes a more senior manager. The question they are really asking is not whether you can do the work but whether they would trust a number that came from you. That changes what a good answer looks like. Lead with what the decision cost and what it changed, keep the method available but not central, and be plain about the limits of your evidence. Overstating a result is the fastest way to lose this round.

What to demonstrate

  • Whether you can explain a technical choice to someone who will never read your code, without either flattening it into nothing or hiding inside jargon
  • Honesty about evidence strength: what the analysis establishes, what it only suggests, and what it cannot say at all
  • How you take disagreement, specifically whether you update on a good objection, hold your position with reasons, or fold on contact

How to prepare

  • Write the two-sentence version of your most technical project for a non-specialist, then check that neither sentence needs a method name to make sense.
  • For one result you are proud of, write the strongest objection someone could raise and a response that concedes the part of it that is correct.
  • Prepare one decision that turned out to be wrong: how you found out, what it cost, and what you changed afterwards. A senior cross-functional interviewer asks for this more often than a technical one does.
PracHub interview research ↗
04

Practical Exercises

reported

Because the format is not fixed, prepare the reasoning rather than the ritual. Nearly every version of this round draws on the same underlying material: a design you can defend, a metric you can define exactly, an analysis whose assumptions you can state out loud. Only the wrapper changes, whether that is a take-home, a live case, a deep dive on past work, or a rough estimate on a whiteboard. Answers rehearsed to fit one shape stall the moment the shape differs. Practise naming the assumption behind a number, then saying how much the conclusion moves if that assumption is wrong.

What to demonstrate

  • Whether your justification for a method survives the question 'why not the simpler thing', including when the simpler thing would have worked
  • Precision under pressure: what exactly counts as an active user, a conversion or a success, over what window, with what exclusions
  • Whether you carry an argument through to a recommendation instead of stopping at a list of tradeoffs

How to prepare

  • For each project you plan to mention, write the metric definition in one sentence: numerator, denominator, time window, exclusions. Say it out loud once, because vagueness shows up in speech before it shows up on paper.
  • Rehearse the same project at three lengths: two minutes, ten minutes, and a deep dive on one technical decision. Cutting live is harder than it sounds.
  • For your headline result, write down what would have had to be true for it to be wrong, and how you ruled that out.
PracHub interview research ↗
05

Technical Evaluations

reported

This round decides whether someone can hand you a schema and a question and trust the number that comes back. Correctness under a clock is the bar, not clever syntax. The habit that separates strong from weak answers is checking the grain: after every join, know how many rows you expect and whether the count moved. Most wrong answers in this format are not wrong logic, they are a fan-out from a key that turned out not to be unique, or a filter applied before an aggregate when it belonged after. Say what you expect before you run it.

What to demonstrate

  • Whether your row counts survive each join, and whether you notice on your own when they do not
  • Deliberate handling of rows that fail to match, including whether the question needs an inner join or a left join with the non-matches kept and counted
  • Whether NULLs are treated on purpose, given that a NULL compares equal to nothing and that COUNT of a column skips it
  • Reaching a defensible answer inside the window instead of a refined one after it

How to prepare

  • Take a two-table schema, write a join that fans out on purpose, then fix it by collapsing the many-side to one row per key before joining. Repeat until the fix is reflex rather than recall.
  • Write a funnel as one query and print the distinct user count at each stage, then confirm each stage is a subset of the one above it rather than assuming it
  • Do a few timed runs in a plain text box with no autocomplete and no formatter, since assessment editors often have neither
PracHub interview research ↗

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

Ignoring clustering by provider, facility, or site

Patients within a provider panel, and subjects within a trial site, are correlated on both case mix and practice pattern. Standard errors computed as if observations were independent are too narrow by roughly the design effect, 1 + (m - 1) * ICC, where m is the average cluster size. With 50 patients per provider and an intracluster correlation of only 0.02, variance is understated by about a factor of two, which manufactures significant provider differences out of noise. Cluster-robust errors or a random intercept per provider, and cluster-level randomisation when you design the test, are the corrections.

03

Reaching for a model before the target metric exists

Before naming an algorithm, write down the label, the prediction time, and the action that changes when the score crosses a threshold. If you cannot say what decision the output drives, any modelling choice is guesswork dressed up as method.

04

Analysing at a different unit than the one randomised

Say out loud what was randomised (user, device, account, cluster) and make the analysis unit match, or account for the clustering with cluster-robust standard errors, the delta method, or aggregation up to the randomised unit. Randomising users and then running a test over sessions understates variance and inflates the false-positive rate.

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

8 technical prompts3 include a worked solution

Can you explain the trade-offs between different classification algori…

medium
machine learning and modelling

Can you explain the trade-offs between different classification algorithms in a clinical setting?

Approach
  1. Check what information would not exist at prediction time, and exclude it.
  2. Set a baseline first, so any model has something honest to beat.
  3. Say how the offline result would be validated online before it is trusted.
Follow-up
  • How would you choose the decision threshold, and who owns that choice?
  • Where could label leakage enter this setup?

How do you approach documentation for your code and model development …

medium
machine learning and modelling

How do you approach documentation for your code and model development process?

Approach
  1. Say how the offline result would be validated online before it is trusted.
  2. Pick an evaluation metric that matches the cost of each error type, not a default.
  3. Set a baseline first, so any model has something honest to beat.
Follow-up
  • How would you choose the decision threshold, and who owns that choice?
  • Where could label leakage enter this setup?

Build a claims lag triangle and complete recent months

mediumWorked solution
chain ladderrunoutpivot

medical_claim_line has claim_id, claim_version, frequency_code, service_start_date, paid_date, allowed_amount, claim_status. Using 24 fully mature incurred months, build a development triangle of allowed dollars by incurred month and payment lag in whole months, derive cumulative completion factors by chain ladder, then estimate ultimate allowed for the three most recent incurred months at a stated paid-through date. Deduplicate to surviving claim versions before building the triangle. Return incurred_month, paid_to_date, completion_factor, estimated_ultimate.

Approach
  1. Deduplicate to surviving claim versions and keep paid lines first. A triangle built on all versions develops on adjustment churn rather than on payment timing, and replacements arrive late, so the distortion concentrates in exactly the tail you are trying to estimate.
  2. Compute lag as a whole-month difference between incurred month and paid month, not as day difference divided by 30. Ragged month lengths otherwise shuffle identical claims between lag buckets depending on which month they fall in.
  3. Pivot to incurred_month by lag, cumulate along lag, then form age-to-age factors as the ratio of the column L+1 total to the column L total, summed over incurred months mature enough to have both. Volume weighting is the chain ladder; a simple mean of per-month ratios lets one low-volume month dominate the factor.
  4. Chain the age-to-age factors from each lag to ultimate and invert: completion factor at lag L is the reciprocal of the product of factors from L onward. Apply as estimated_ultimate = paid_to_date / completion_factor.
  5. State the assumption you have just made, which is that the development pattern is stable. It is not, after a claims-system migration, a network change or a processing backlog, and the most recent month's factor is the least reliable because it rests on the fewest observations while carrying the largest adjustment.
Worked solution 35 min
  1. Deduplicate to surviving versions, drop voids, keep claim_status 'paid', and derive incurred_month from service_start_date and paid_month from paid_date.
  2. lag = (paid_month.year - incurred_month.year) x 12 + (paid_month.month - incurred_month.month); drop negative lags and investigate them separately.
  3. Pivot to a triangle of summed allowed_amount, cumulate along the lag axis, and mask cells past the paid-through date so no cell contains a future payment.
  4. Compute volume-weighted age-to-age factors per lag over the mature rows, then chain them into cumulative completion factors.
  5. Apply the factor for each recent month's current maturity to its paid_to_date and return the four columns.
EXPECTED RESULTThree rows. Completion is well below 1 at short lag and approaches 1 in the tail; for a mixed medical book a one-month-old incurred month commonly sits far from complete, while a twelve-month-old one is close. Exact values are book-specific, so the reviewable property is monotonicity and the holdout test below, not the numbers themselves.
Follow-up
  • A processing backlog means the last two months developed slower than history. What does your estimate do, and how would you detect that before reporting?
  • Pharmacy, professional and inpatient facility develop on different clocks. How do you split the triangle, and what breaks if the service mix shifts?
  • What happens to a PMPM series if someone reports an unadjusted recent month, and in which direction does the error point?

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 ↗
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.

Work that nobody used is a common and unflattering pattern in data careers, and interviewers probe for it. Have a story about an analysis that changed a decision, and be specific about how you got it in front of the person who could act. Also have one about work that went nowhere, with your reading of why.

Describe a time you had a conflict with a manager; how did you resolve…

medium
behavioural and stakeholder questions

Describe a time you had a conflict with a manager; how did you resolve it?

Approach
  1. Quantify the outcome, including what you would not claim credit for.
  2. State the situation in two sentences and spend the rest on your reasoning.
  3. Close with what you would do differently, concretely.
Follow-up
  • What would you do differently if you ran that project again?
  • How did you know the outcome was caused by your change?

Describe a time you had to explain a complex model to a stakeholder wi…

medium
behavioural and stakeholder questions

Describe a time you had to explain a complex model to a stakeholder without a data background.

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

Tell us about a project where you had to pivot due to changing require…

medium
behavioural and stakeholder questions

Tell us about a project where you had to pivot due to changing requirements or data limitations.

Approach
  1. State the situation in two sentences and spend the rest on your reasoning.
  2. Quantify the outcome, including what you would not claim credit for.
  3. Close with what you would do differently, concretely.
Follow-up
  • How did you know the outcome was caused by your change?
  • What would you do differently if you ran that project again?
  • 01

    Describe a time you had a conflict with a manager; how did you resolve it?

  • 02

    Describe a time you had to explain a complex model to a stakeholder without a data background.

  • 03

    Tell us about a project where you had to pivot due to changing requirements or data limitations.

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

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

PracHub interview research ↗
How much time should I set aside for the interview process?

Expect the process to take several weeks from the initial screen to the final decision. Ensure you have flexibility for a technical assignment, as these are sometimes part of the evaluation.

PracHub interview research ↗
What is the most common reason candidates do not move forward?

Often, it is a lack of focus on the "why." Candidates who can explain the clinical or business implications of their models perform significantly better than those who focus purely on the technical implementation.

PracHub interview research ↗
Is there a specific coding language I should prioritize?

While both Python and R are used, being able to explain your logic clearly is more important than the specific tool. If you are stronger in one, be prepared to explain why it is the right choice for the problem at hand.

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.