AKKODIS · Data Scientist
Updated · 2026-09-24

AKKODIS Data Scientist
Interview Questions & Guide 2026

THE 60-SECOND BRIEF

As a Data Scientist at AKKODIS, you occupy a unique and highly impactful position at the intersection of advanced analytics, engineering, and strategic consulting. AKKODIS is a global leader in the engineering and R&D market, meaning your work will directly influence smart industry solutions across diverse sectors such as automotive, aerospace, defense, energy, and life sciences. Unlike traditional in-house data roles, your expertise will be deployed to solve complex, real-world problems for major global clients, making adaptability and technical breadth your greatest assets.

In modelling rounds the live question is usually why this model class for this problem, and how you would know six weeks after launch that it is still working. Deriving gradients by hand is rarely what is being probed.

AKKODIS candidates report 3 rounds · ≈ 3-5 weeks. The stages below are what candidates describe, not a published process.

Segment margin by pricing model before comparingCompute utilisation against a defended availability denominatorSeparate bookings, recognised revenue and collected cash

30 min read

Browse Data Scientist questions

See the practice prompts

14Practice promptsAcross five skill areas
3With worked solutionsIncluded in the practice prompts

As a Data Scientist at AKKODIS, you occupy a unique and highly impactful position at the intersection of advanced analytics, engineering, and strategic consulting. AKKODIS is a global leader in the engineering and R&D market, meaning your work will directly influence smart industry solutions across diverse sectors such as automotive, aerospace, defense, energy, and life sciences. Unlike traditional in-house data roles, your expertise will be deployed to solve complex, real-world problems for major global clients, making adaptability and technical breadth your greatest assets.

You will be responsible for translating massive, often unstructured datasets into actionable business intelligence and predictive models. Whether you are optimizing supply chains, developing predictive maintenance algorithms for industrial machinery, or building computer vision models for autonomous systems, your contributions will drive tangible operational efficiency. The role demands not only rigorous mathematical and programming skills but also the ability to communicate technical findings to stakeholders who may not have a data science background.

This position is ideal for professionals who thrive on variety and continuous learning. Because AKKODIS operates on a project- and client-driven model, you will have the opportunity to work on diverse tech stacks and domain challenges. Your ability to quickly understand a client's business model, identify data-driven opportunities, and deliver clean, production-ready code is what will set you apart as a high-performing Data Scientist within the organization.

01

Initial Screening Call

reported

Most candidates lose this call inside the first two minutes, during the walkthrough of their own background. The account runs chronologically, sits at the level of tools and titles, and never arrives at a decision anyone could have disagreed with. Anchor on a problem instead of a timeline: what the team could not answer, what you did about it, what happened next. Ninety seconds is enough, and stopping on time leaves room for the half of the call that belongs to you. What you ask about how work gets prioritised signals your level more reliably than the walkthrough does.

What to demonstrate

  • Whether your background summary has a shape (problem, decision, consequence) or is a chronological list of tools and employers
  • Whether you can account for gaps, short stints and the reason you are looking, unprompted and without hedging
  • The substance of the questions you ask back, which an experienced screener reads as a level signal

How to prepare

  • Time your opening walkthrough against a clock. If it runs past two minutes, compress the earliest role into a single clause and spend the recovered time on the most recent one
  • Write one honest sentence for every gap or short stint visible on your resume and offer it before being asked about it
  • Prepare questions about how work arrives and gets prioritised: who writes the request, how often priorities change, and what happens to an analysis after it is delivered
PracHub interview research ↗
02

Technical and Managerial Evaluation

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 ↗
03

Final Client Interview

reported

A day of back-to-back interviews samples your floor, not your ceiling. Four hours in, the habits that carry a good answer are the first to go: restating the question before solving it, asking what the data would have to look like, checking a number before quoting it. What the day decides is whether the tired version of you is still someone to leave alone with an ambiguous problem. The round that sinks a candidate is usually not the hardest one. It is the one immediately after the round that went badly.

What to demonstrate

  • Whether the late rounds get the same clarifying questions as the first one, or whether you start answering immediately to save effort
  • Whether a weak answer stays in the room it happened in, instead of following you into the next conversation as apology or distraction
  • Whether the quality of your questions holds up, since fatigue removes curiosity about the problem before it removes knowledge of the method

How to prepare

  • Rehearse the length, not just the content: book four mock interviews of different types in one afternoon with short gaps, because the one you need to observe is the fourth
  • Put the two or three questions you ask at the start of any problem on a card in front of you, so that under fatigue it is a habit you run rather than a decision you make
  • Decide in advance what the gap between rooms is for: water, one line of notes on anything you promised to follow up, and an explicit close on the round that just ended so it does not travel
  • Prepare a different closing question for each interviewer, so the end of a long day does not produce the same one four times
PracHub interview research ↗

PracHub editorial advice for the preparation topics above.

01

Pooling margin, realisation or overrun across pricing models

Fixed-fee margin falls with hours worked; uncapped time-and-materials margin rises with hours worked; retainer margin depends on neither. A quarter in which the firm sells more fixed-fee work will show a margin change caused entirely by mix, not by delivery performance, and the aggregate can move in the opposite direction to every individual pricing model. Always stratify by fct_engagement.pricing_model before comparing periods, and report the mix shift alongside the within-stratum change.

02

Trending utilisation or revenue on work_date without accounting for timesheet backfill

Time entries are created days to weeks after the work happens, and the backfill tail often runs two to six weeks. A dashboard keyed on work_date therefore shows the most recent weeks as a decline that reverses on every refresh. The fix is either to hold the reporting window back past the observed backfill tail (measure the tail with the timesheet submission lag metric rather than guessing) or to report an as-of-entered_at snapshot so the series is internally consistent, and to state which one you used.

03

Interpreting a change before checking data quality and logging

Spend the first pass on row volume by day, null rates, duplicate keys, and whether the step change lands on a release or tracking-migration date. A discontinuity that coincides with a deploy is an instrumentation hypothesis before it is a behavioural one.

04

Over-explaining the method and under-explaining the implication

Lead with the answer and what you would do about it, then give the approach when asked. Roughly one sentence of method per three of implication is the right ratio for a stakeholder-facing answer; the interviewer already knows what a regression is.

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

11 technical prompts3 include a worked solution

Walk me through a machine learning project you completed. What was the…

medium
machine learning and modelling

Walk me through a machine learning project you completed. What was the business problem, and how did you design the solution?

Approach
  1. Set a baseline first, so any model has something honest to beat.
  2. Pick an evaluation metric that matches the cost of each error type, not a default.
  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 address the issue of class imbalance in a classification da…

medium
machine learning and modelling

How do you address the issue of class imbalance in a classification dataset?

Approach
  1. Set a baseline first, so any model has something honest to beat.
  2. Frame the prediction: the label, the moment of prediction, and the action it triggers.
  3. Say how the offline result would be validated online before it is trusted.
Follow-up
  • What would you monitor after launch to know the model is still valid?
  • Where could label leakage enter this setup?

Measure the timesheet backfill curve and pick a reporting cutoff

easyWorked solution
late-arriving datadata qualitycohort curves

time_entries has work_date (date), entered_at (timezone-aware UTC timestamp), hours and status. Given a snapshot_date, restrict to work_date in [snapshot_date - 180 days, snapshot_date - 60 days] so every cohort is fully observed. For k = 0..45, compute F(k): the share of a work_date cohort's final hours that already existed as of work_date + k days, pooled across cohorts. Return the 46-point curve and the smallest k with F(k) >= 0.99. Some rows are entered before the work date; those lags are real, not errors.

Approach
  1. Compute lag = (entered_at converted to the reporting timezone and taken as a date) - work_date in whole days, then clip negative lags to 0 instead of dropping them; leave and planned time are routinely entered ahead of the work date and dropping them deflates the early curve.
  2. Take cohort totals as groupby(work_date).hours.sum() over the restricted window. These are final only because the window stops 60 days short of the snapshot, which is why the restriction is in the prompt.
  3. Build the numerator by summing hours per (work_date, lag), sorting by lag, taking a per-cohort cumsum, then reindexing each cohort onto the full 0..45 lag grid and forward-filling, so a cohort with no entries at a given lag holds its previous level rather than disappearing.
  4. Pool as sum(numerators) / sum(denominators) at each k, not as the mean of per-cohort shares. Holiday weeks are tiny cohorts and would otherwise carry the same weight as a full week.
  5. Read k* off the pooled curve and report F(45) with it: if F(45) is below about 0.995 the tail runs past the grid and k* is a lower bound, not the answer.
Worked solution 25 min
  1. Restrict rows to the [snapshot - 180d, snapshot - 60d] window and compute lag_days = (entered_at.dt.tz_convert(tz).dt.normalize().dt.date - work_date).dt.days, then lag_days = lag_days.clip(lower=0).
  2. cohort_total = df.groupby('work_date').hours.sum(); by_lag = df.groupby(['work_date','lag_days']).hours.sum().
  3. Reindex by_lag onto MultiIndex.from_product([cohorts, range(0,46)]), fill 0, cumsum within work_date to get hours_by_k.
  4. F = hours_by_k.groupby(level='lag_days').sum() / cohort_total[cohorts_in_grid].sum(); assert F is non-decreasing.
  5. k_star = int(F[F >= 0.99].index.min()) if any, else report 'not reached within 45 days' along with F(45).
EXPECTED RESULTA monotone non-decreasing 46-point series F(0)..F(45) bounded by 1.0, plus an integer k* (or an explicit 'not reached by day 45') reported together with the value of F(45).
Follow-up
  • The dashboard refreshes daily. Would you hold the window back past k*, or publish an as-of-entered_at series instead, and what does each choice cost the reader?
  • One practice area has a tail twice as long as the rest. Does that change the firm-wide cutoff, or does it change what you publish per practice area?

Roughly 90 minutes a night on weekdays with one longer weekend block. The plan deliberately cuts scope rather than compressing everything, on the assumption that finishing one thing a night beats half-starting four.

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
01Fix the scope and set a baseline
  • Read the role description and write the three things the loop will almost certainly test, then write an explicit not-doing list for everything else and keep it visible all week.
  • Take one 20-minute SQL prompt and one 10-minute metric question cold, and write the single sentence that says what blocked each attempt, since that sentence is what decides which two topics get the most evenings.
  • Set the week's one rule: one problem finished to completion every night, including the night you only have 40 minutes.

Deliverable: A one-page scope with an explicit not-doing list and two cold attempts, each carrying one sentence on what blocked it.

Practice prompt ↗Practice prompt ↗Worked solution ↗
02One query pattern, written three times
  • Choose the single pattern most likely to appear (a cohort retention grid, or a funnel counted by user) and write it three times from a blank file rather than editing the previous attempt.
  • On the third attempt, write the grain of every CTE as a comment before writing its body.
  • Stop at 90 minutes even if the third version is imperfect, and write the one thing you would fix with another hour.

Deliverable: Three independent versions of the same query plus a note on what changed between them.

Practice prompt ↗Practice prompt ↗
03Only the statistics you will be asked to defend
  • Write, in under 200 words, how you would decide whether a difference between two groups is real: the test, its assumptions, and what you would switch to when an assumption fails.
  • Compute a 95 percent confidence interval for a difference in proportions by hand on realistic numbers, then write in one sentence what changes if the two samples are paired rather than independent.
  • Write your answer to "what does a p-value mean", check it against a definition, and delete the version that describes it as the probability the hypothesis is true.

Deliverable: A 200-word written answer and one hand-computed interval you can reproduce under pressure.

Practice prompt ↗Practice prompt ↗
04One case, and the assumptions holding it up
  • Answer one product case aloud in 20 minutes with a recording running, then listen back with a pen and mark every claim you asserted without saying what it rested on: an assumed user behaviour, an assumed data source, an assumed baseline rate, an assumed grain.
  • Pick the three assumptions the recommendation actually depends on, write how you would check each one against data, and say which one being wrong would flip the recommendation rather than merely weaken it.
  • Write the four-step structure you used onto a card small enough to hold in working memory when you are nervous.

Deliverable: One recording, three load-bearing assumptions each with a written check, and a four-step structure card.

Practice prompt ↗Practice prompt ↗Worked solution ↗
05Your own work, timed
  • Write a 90-second version and a four-minute version of your main project, and time both out loud rather than reading them.
  • Prepare answers to the two follow-ups that always come: what you would do differently, and how you knew it worked.
  • Put one number in the first sentence and be able to say exactly where that number came from and what it excludes.

Deliverable: Two timed narratives with one defensible number in the opening line.

Practice prompt ↗Practice prompt ↗
06The one full rehearsal, in a longer weekend block
  • Run a 60-minute mock covering query work, a case and a behavioural question in a single sitting with no breaks, because sustained attention is the thing evenings have not trained.
  • Immediately afterwards, and before hearing any feedback, write the three moments you lost the thread.
  • Spend the rest of the block only on those three moments, and on nothing you merely feel shaky about.

Deliverable: Mock notes naming three failure moments with a specific fix written under each.

Practice prompt ↗Practice prompt ↗
07Taper
  • Write the 20-minute warm-up you will actually do on the morning of the interview: one query you can already write from a blank file, one metric you can define out loud, and nothing you have never seen before.
  • Re-read only your own notes from this week, and open no new material.
  • Write down the logistics: the tool you will be asked to work in, whether lookups are allowed, and the sentence you will use when you do not know something.

Deliverable: A one-page card holding the case structure, the project numbers, and the logistics.

Practice prompt ↗Practice prompt ↗Worked solution ↗

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

Data people depend on systems owned by other teams, and much of the job is negotiating for instrumentation, access, or a fix to a broken pipeline. Prepare an example of getting something changed upstream that you did not control. Describe what you asked for, what you traded, and how you worked while you waited.

Describe a time when a project's requirements changed midway through d…

medium
behavioural and stakeholder questions

Describe a time when a project's requirements changed midway through development. How did you adapt?

Approach
  1. Close with what you would do differently, concretely.
  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
  • What would you do differently if you ran that project again?
  • What did you decide not to do, and why?

How do you handle missing or corrupted data in a large dataset using P…

medium
behavioural and stakeholder questions

How do you handle missing or corrupted data in a large dataset using Pandas?

Approach
  1. Close with what you would do differently, concretely.
  2. Pick a story where you drove the decision, not one where you observed it.
  3. Name the disagreement or constraint, and how you resolved it with evidence.
Follow-up
  • What did you decide not to do, and why?
  • How did you know the outcome was caused by your change?

Defending your own impact claim without randomisation or clean units

hard
self-selectionclustered inferenceimpact measurement

At your review you plan to claim that the realisation dashboard you built recovered 1.4 million dollars. The evidence is that engagement-month realisation rose four points over two quarters among engagements whose leads used it. Adoption was voluntary. There are about sixty client accounts and the top five carry most fees. A new rate card shipped in the same quarter. Write the claim you can defend, the estimate you would actually produce, and what you say when asked for a causal number you cannot get.

Approach
  1. Name the probe: whether you can separate the number you want from the number the data supports, under review pressure, without either inflating it or retreating to saying nothing can be known.
  2. State both identification problems concretely. Voluntary adoption means adopting leads are plausibly the ones who already manage realisation, so the comparison is confounded at the person level. The rate card changes bill_rate_usd, which sits in the realisation denominator, so part of the four-point move is arithmetic rather than behavioural.
  3. Neutralise what you can. Recompute realisation with bill rates snapshotted on work_date, or hold the denominator at the old rate card, so the rate-card change cannot move the metric by construction. Then rerun the comparison.
  4. Get the inference right for the unit count. Cluster at client_id, not engagement, because engagements in one account share a partner, a rate card and a team. With sixty accounts and five carrying most fees, the effective cluster count is far below sixty, so report a wild cluster bootstrap interval rather than plain cluster-robust standard errors, which are biased downward in that regime.
  5. Report both weightings and explain the divergence: an account-weighted estimate describes the typical account, a value-weighted one describes the revenue, and if they disagree a small number of accounts is carrying the result. Then give the decision-relevant sentence: the defensible range, whether its lower bound still clears the build cost, and what a proper staggered rollout would have bought.
Follow-up
  • The pre-period trends for adopters and non-adopters are not parallel. What do you report then?
  • You get to design the next rollout. What do you change so the same question is answerable, without randomising individual accounts?
  • 01

    Describe a time when a project's requirements changed midway through development. How did you adapt?

  • 02

    How do you handle missing or corrupted data in a large dataset using Pandas?

  • 03

    At your review you plan to claim that the realisation dashboard you built recovered 1.4 million dollars. The evidence is that engagement-month realisation rose four points over two quarters among engagements whose leads used it. Adoption was voluntary. There are about sixty client accounts and the top five carry most fees. A new rate card shipped in the same quarter. Write the claim you can defend, the estimate you would actually produce, and what you say when asked for a causal number you cannot get.

PracHub interview preparation framework ↗
Is this an official AKKODIS interview guide?

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

PracHub interview research ↗
How technical is the AKKODIS Data Scientist interview process?

The technical depth is generally practical and project-focused rather than highly theoretical. You should expect to discuss your past projects, Python coding practices, and basic machine learning concepts in detail, rather than facing intense, abstract algorithmic coding challenges.

PracHub interview research ↗
How long does the hiring process typically take?

The timeline can vary from two weeks to over a month. Because AKKODIS matches candidates with client projects, the speed of the process often depends on active client demands and project availability in your specific region.

PracHub interview research ↗
Will I be interviewing with AKKODIS managers or the client?

You will typically experience both. The initial rounds are conducted by AKKODIS HR and technical managers to assess your core skills. Once a potential project match is identified, you will often have a final technical conversation with the client's team.

PracHub interview research ↗
What is the work model (remote/hybrid) for Data Scientists?

AKKODIS generally supports hybrid working arrangements. However, the exact balance between remote work, office time, and client-site visits depends heavily on the specific project and client requirements.

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.