First National Bank Of Pennsylvania · Data Scientist
Updated · 2026-09-22

First National Bank Of Pennsylvania Data Scientist
Interview Questions & Guide 2026

THE 60-SECOND BRIEF

As a Data Scientist at First National Bank Of Pennsylvania, you serve as a critical bridge between complex financial datasets and actionable business strategy. You are tasked with developing analytical models that drive decision-making across the institution, influencing everything from risk assessment and fraud detection to personalized customer banking experiences. Your work directly impacts the bank’s ability to navigate a competitive financial landscape by uncovering insights that optimize operational efficiency and growth.

The boundary with engineering varies enough to be worth asking about directly. Some seats end at the analysis and the writeup; others carry feature pipelines, scheduling and alerting, which decides whether production data plumbing belongs in your prep at all.

First National Bank Of Pennsylvania candidates report 3 rounds · ≈ 3-5 weeks. The stages below are what candidates describe, not a published process.

Decompose expected loss into PD, LGD, EADRead vintage curves, not blended portfolio averagesReconcile amounts in minor units and currency

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13Practice promptsAcross five skill areas
3With worked solutionsIncluded in the practice prompts

As a Data Scientist at First National Bank Of Pennsylvania, you serve as a critical bridge between complex financial datasets and actionable business strategy. You are tasked with developing analytical models that drive decision-making across the institution, influencing everything from risk assessment and fraud detection to personalized customer banking experiences. Your work directly impacts the bank’s ability to navigate a competitive financial landscape by uncovering insights that optimize operational efficiency and growth.

This role requires a high degree of technical rigor combined with the ability to translate complex statistical findings into clear, persuasive narratives for non-technical stakeholders. You will be operating within a data-driven culture where your contributions are expected to be both scientifically sound and commercially viable. Success in this position means you are not just building models, but helping First National Bank Of Pennsylvania solve foundational problems that maintain its standing as a trusted financial partner.

01

HR Screen

reported

Whoever runs this call is usually not a practitioner. They take notes, and a hiring manager skims those notes later, so the real question is whether your work survives being written down by someone outside the field. Test every project sentence against that: could a non-specialist repeat it correctly without knowing what a propensity score is? Carry a plain-language version of each project and one reason you want this particular role that you could not copy onto another application. Vagueness at this stage reads as inexperience, even when the underlying work was genuinely deep.

What to demonstrate

  • Whether a non-specialist can restate your projects accurately, since their paraphrase is what reaches the hiring manager
  • Whether your reason for wanting the role points at the work itself rather than the company's reputation
  • Whether your language signals the level being screened for: what you decided yourself versus what you were handed

How to prepare

  • Write a two-sentence, jargon-free version of each major project: the question nobody could answer, and the decision your work changed. Read it to someone outside data and have them repeat it back
  • Point your 'why this role' answer at something concrete in the job description or the product surface you would be working on, and keep it to two sentences
  • Have two questions ready about measurement: which metric the team is held to, and who acts on an analysis once it lands
PracHub interview research ↗
02

Technical Interviews

reported

Before anything else, this round is a reading test. You are given a small schema and a question phrased in business language, and most of the difficulty sits in the gap between them. Who counts as an active user, does a refunded order still count as an order, is that date column an event time or a load time. Weak answers start typing immediately and compute something precise about the wrong population. Strong ones pin the definition in one sentence, name the column that encodes it, then write the query. On a timed assessment with nobody to tell, write the definition in a comment anyway.

What to demonstrate

  • Whether an ambiguous term becomes a specific column and filter before any computation happens
  • Whether you read the schema for keys and cardinality rather than only for column names
  • Whether the result answers the question at the grain it was asked at, per user or per session or per day

How to prepare

  • Take three metrics you already use and write down the exact filter and exact grain behind each, then practise stating one of them in a single sentence out loud
  • On a schema you have never seen, spend the first minute writing what one row of each table means and which key it is unique on, then predict which joins can duplicate rows
  • Rehearse a version where the definition changes halfway through, and edit the query you have instead of starting over
PracHub interview research ↗
03

Final Round

reported

A loop is not scored one interview at a time. The people you meet compare notes afterwards, usually in a meeting you are not in, and the outcome turns on what each of them can say about you when asked. That rewards something other than survival: every room needs one specific thing worth repeating, and none of them can contradict another. The common way to lose is to tell the same project four times with different numbers in it, or to be uniformly fine in a way that leaves nobody with anything to argue for.

What to demonstrate

  • Whether your account of a project survives being told twice, with the same scale, the same metric definition and the same numbers each time
  • Whether each interviewer leaves with one concrete claim they could make on your behalf later, rather than an absence of complaints
  • Whether a question you already answered in an earlier room gets the same answer at the same depth, without visible impatience

How to prepare

  • Write a one-page fact sheet for your two or three main projects that fixes the numbers you will quote: rows of data, the metric as a single sentence, the effect you measured and how long the work took. Say them aloud from the sheet until they come out identical every time
  • For each kind of room you expect, decide the one sentence you want that interviewer repeating in a debrief, then check during the mock that you said it outright instead of implying it
  • Rehearse answering the same project question twice in one sitting, the second time as though you had not just answered it, because the thing that needs fixing is the flatness that creeps into a repeated story
PracHub interview research ↗

PracHub editorial advice for the preparation topics above.

01

Reading the most recent months of fraud and dispute rates as final

Consumer dispute rights commonly run around 120 days from the transaction or expected delivery date, and several reason codes run considerably longer, so the disputes belonging to a recent transaction month have simply not been filed yet. Any chart attributed by transaction date therefore slopes down at the right edge regardless of what is happening. The fix is to report only matured cohorts, or to apply development factors estimated from completed months and to show the estimate as an estimate.

02

Recalibrating an underwriting cutoff on approved and funded applicants only

Rejected applicants have no repayment outcome, and they were rejected because the incumbent model scored them badly, so the missingness depends directly on the outcome being modelled. Reject inference by augmentation or parcelling fills the gap using the incumbent model's own assumptions, which means it can confirm those assumptions but cannot test them. The only genuinely new information about the reject region comes from bureau performance on rejects who borrowed elsewhere, or from a deliberately randomised approval band around the cutoff.

03

Accepting a metric definition without asking about the denominator

Pin down the denominator, the eligibility filter and the time window before computing anything: conversion rate per session, per user, per eligible user and per new user are four different numbers with different behaviour. Restate the definition in one sentence and get agreement before you analyse.

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.

10 technical prompts3 include a worked solution

How did you validate your model's performance in a real-world scenario…

medium
machine learning and modelling

How did you validate your model's performance in a real-world scenario?

Approach
  1. Pick an evaluation metric that matches the cost of each error type, not a default.
  2. Frame the prediction: the label, the moment of prediction, and the action it triggers.
  3. Set a baseline first, so any model has something honest to beat.
Follow-up
  • What would you monitor after launch to know the model is still valid?
  • How would you choose the decision threshold, and who owns that choice?

How did you choose the specific algorithm for this project over other …

medium
machine learning and modelling

How did you choose the specific algorithm for this project over other alternatives?

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

Collapse retry chains and compute a dollar-weighted approval rate

mediumWorked solution
sessionisationwindow functionsdollar-weighted rates

fct_payment_authorization gives auth_id, card_token_id, merchant_id, amount_minor, transaction_currency, requested_at, auth_result, is_reversal, channel and issuer_country. Two reference frames give the minor-unit exponent per currency and a daily rate to one reporting currency. Collapse retry chains first: attempts sharing card_token_id, merchant_id and amount_minor whose consecutive gaps are under 15 minutes form a single attempt, whose outcome is its last row. Exclude reversals and zero-amount verifications. Return a 7-day rolling dollar-weighted approval rate by channel and issuer_country.

Approach
  1. Filter before grouping: drop is_reversal rows and zero-amount verifications, since neither is a purchase attempt and both would otherwise sit in the denominator.
  2. Sort by card_token_id, merchant_id, amount_minor and requested_at, take the gap to the previous row within that key, mark a chain start where the gap exceeds 15 minutes or the key changes, and label chains with a cumulative sum of that flag. This is a gap rule between consecutive attempts, not a fixed clock bucket, so a chain may span more than 15 minutes in total.
  3. Keep each chain's terminal row by requested_at. If a retry was approved, the purchase was approved; keeping the first row reports the decline that caused the retry as the outcome.
  4. Convert amounts exactly once: amount_minor divided by 10 to the power of the currency exponent, multiplied by the reference rate for the authorization date. Do not reach for settlement_fx_rate, which is null on precisely the declined rows the denominator needs.
  5. Build the rolling window as a ratio of two rolling sums, approved value over total value, per channel and issuer_country. A rolling mean of daily ratios weights a quiet Sunday the same as a busy Friday.
Worked solution 35 min
  1. Filter out reversals and zero-amount rows, then sort by the chain key and requested_at.
  2. Compute the within-key time difference, derive the chain start flag and the chain id, and take the last row per chain with groupby(chain_id).tail(1) after sorting.
  3. Join the exponent and daily rate tables, compute value_reporting, and assert no nulls remain after the join.
  4. Aggregate approved value and total value to a daily grain by channel and issuer_country, reindex to a complete date range per group so missing days are zero rather than absent.
  5. Take 7-day rolling sums of both columns and divide, then confirm one hand-picked group-day against a direct filter.
EXPECTED RESULTA DataFrame keyed by date, channel and issuer_country with approved_value, total_value and approval_rate. The collapsed attempt count is materially below the raw row count, with the gap concentrated in declined ecommerce rows, and ecommerce sits below card_present.
Follow-up
  • The count-weighted rate is flat while the dollar-weighted rate falls 80 basis points. What do you look at first?
  • How would you choose the 15-minute window rather than inheriting it?
  • A merchant moves from two retries to five. Which of your two rates moves, and is that a real change in approval quality?

For someone who has spent the last year in notebooks, dashboards or modelling work and has not written raw SQL under time pressure. The first four days rebuild query fluency against a fixture you control and can verify by hand; the last three attach that fluency to the rest of the loop.

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
01Build a fixture you can check answers against
  • Create a local Postgres or SQLite database with four tables (users, sessions, events, orders) holding roughly 200 rows you generated yourself, so you know the contents well enough to predict every result.
  • Deliberately seed the cases that break queries: a user with no sessions, a session with no events, two orders sharing a timestamp, a NULL in one join key, and one duplicated user row.
  • Before writing any SQL, hand-compute five answers on paper (how many users placed at least one order, median orders per ordering user, and three others) and save them as the ground truth for the week.

Deliverable: A one-command seed script plus a text file of five hand-computed answers to grade every later query against.

Practice prompt ↗Practice prompt ↗Worked solution ↗
02Joins, filters and NULL semantics
  • Answer "which users have no orders" three ways (LEFT JOIN with IS NULL, NOT EXISTS, NOT IN) and confirm that the NOT IN version returns zero rows once the subquery contains a NULL, because the comparison is never TRUE.
  • Reproduce the LEFT JOIN that silently collapses to an inner join by putting a right-table predicate in WHERE, then fix it by moving the predicate into the ON clause, and record both row counts.
  • Create a fan-out bug on purpose by joining orders to order_items and summing the order total, then correct it with a pre-aggregated subquery and explain in one line which table changed the grain.

Deliverable: One annotated .sql file holding the three join traps, each with the wrong result and the corrected result side by side.

Practice prompt ↗Practice prompt ↗
03Window functions and frames
  • Write three window queries against the fixture: a running order total per user, the rank of each order within its user by value, and the day gap to that user's previous order, then check each against the day-one ground truth.
  • Run ROW_NUMBER, RANK and DENSE_RANK over a column containing ties, print all three side by side, and write one sentence on when each is the correct choice.
  • Switch one query from the default frame (RANGE BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW, which is what you get when ORDER BY is present and no frame is written) to ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW, and explain why the output differs only when the ORDER BY column has duplicates.

Deliverable: Three verified window queries plus a short note explaining the RANGE versus ROWS difference in your own words.

Practice prompt ↗Practice prompt ↗
04The four analytical query patterns
  • Write a monthly retention grid: first order month per user, then months-since-first as the column, and verify that month zero equals the cohort size exactly.
  • Sessionize the events table under a 30-minute inactivity rule using LAG plus a cumulative sum over a new-session flag.
  • Build a four-step funnel that counts distinct users rather than events at each step, and state the rule you applied to a user who reaches step three without ever logging step two.

Deliverable: One file with the retention, sessionization and funnel patterns, each carrying a one-line note on the assumption it bakes in.

Practice prompt ↗Practice prompt ↗Worked solution ↗
05Write SQL the way you will have to write it live
  • Set a 12-minute timer and solve three medium prompts in a plain editor with no execution and no autocomplete, then run them and tally syntax errors separately from logic errors.
  • Narrate one solution aloud while writing it, stating the grain of each intermediate result (one row per user, one row per user-day) before you type its body.
  • Rewrite your slowest solution as a CTE chain where every CTE name states its grain, and time yourself re-solving it from blank.

Deliverable: A recording of one narrated solution plus an error tally that separates syntax from logic.

Practice prompt ↗Practice prompt ↗
06One day for everything that is not SQL
  • Write the preconditions of the two-sample t-test from memory, then check them: independent observations, and a difference in means whose sampling distribution is approximately normal, which at large sample sizes follows from the central limit theorem rather than from normality of the raw values.
  • Write the difference between an odds ratio from logistic regression and a relative risk, and state the condition under which the two are close (low outcome prevalence).
  • Prepare a 90-second answer to "how would you know this model is any good" that names the metric, the baseline you would beat, and the cost of the errors you care about.

Deliverable: One page of notes covering test preconditions, the odds-ratio caveat and the model-quality answer.

Practice prompt ↗Practice prompt ↗
07Full loop rehearsal
  • Run a 45-minute mock with someone willing to interrupt: 20 minutes of SQL, 15 minutes defining a metric, 10 minutes on a past project.
  • Re-solve from blank the two queries you were slowest on this week and compare the times against day five.
  • Write a five-line answer to "walk me through a project" that puts a number in the first sentence and names the decision the work changed.

Deliverable: Mock feedback notes plus a timed project narrative you can deliver without reading it.

Practice prompt ↗Worked solution ↗

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

An answer without a quantity is hard to interrogate, so interviewers keep probing until they find one. Come with the baseline, the change, the window it was measured over, and how confident you were. If the effect never got measured, say so and say what you would have measured. Fabricated precision is worse than an honest gap.

Describe a situation where you had to defend your methodology against …

medium
behavioural and stakeholder questions

Describe a situation where you had to defend your methodology against a skeptical team member.

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?
  • What would you do differently if you ran that project again?

How do you manage your time when balancing multiple urgent data reques…

medium
behavioural and stakeholder questions

How do you manage your time when balancing multiple urgent data requests?

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

Retract a published number after finding a currency bug

medium
error disclosureminor unitsprocess repair

Two weeks ago you published an interchange and fraud analysis that summed amount_minor across fct_payment_authorization without converting currencies. Minor units are not two decimals everywhere: some currencies carry none and some carry three, so the sum has no interpretation. A pricing decision is already in flight on the back of it. You now have corrected figures. Produce the retraction: what you send, to whom, in what order, and what you change in the process so this class of error is caught next time rather than trusted next time.

Approach
  1. Size the error before announcing it, because saying the number is wrong without a magnitude and a direction forces every reader to assume the worst case.
  2. Check whether the conclusion actually flips: if the ranking that drove the pricing decision is unchanged, that belongs in the first sentence beside the correction rather than buried at the end.
  3. Tell the person acting on it first and directly, then the wider distribution, using the same text, so nobody learns about it secondhand.
  4. Write the correction as four parts: the old number, the cause in one clause, the effect on the pending decision, and the new number. Leave out self-flagellation, which makes the reader do emotional work instead of acting.
  5. Fix the class rather than the instance: a rule that a sum over amount_minor either groups by transaction_currency or passes through both conversion steps, exponent scaling and then a dated rate into one named reporting currency, plus a standing reconciliation of the settled subset to the settlement ledger inside each settlement_currency.
Follow-up
  • The corrected figures do not change the decision. Do you still send the correction, and what does that choice signal?
  • What automated check would have caught this, where would it live, and what would it cost in false alarms?
  • 01

    Describe a situation where you had to defend your methodology against a skeptical team member.

  • 02

    How do you manage your time when balancing multiple urgent data requests?

  • 03

    Two weeks ago you published an interchange and fraud analysis that summed amount_minor across fct_payment_authorization without converting currencies. Minor units are not two decimals everywhere: some currencies carry none and some carry three, so the sum has no interpretation. A pricing decision is already in flight on the back of it. You now have corrected figures. Produce the retraction: what you send, to whom, in what order, and what you change in the process so this class of error is caught next time rather than trusted next time.

PracHub interview preparation framework ↗
Is this an official First National Bank Of Pennsylvania interview guide?

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

PracHub interview research ↗
How long does the entire interview process usually take?

The process varies, but candidates have reported timelines ranging from a few weeks to over two months. Stay proactive in your communication with the recruiting team to keep the process moving.

PracHub interview research ↗
Should I be prepared for a whiteboarding session?

While the focus is often on your past projects and coding in R or SAS, be prepared to explain your logic on a whiteboard or shared document during technical discussions.

PracHub interview research ↗
How important is industry-specific experience?

While not always mandatory, having a background in banking or finance helps you understand the regulatory environment and the specific types of data issues we face. If you lack this, focus on how your analytical skills can be translated to our specific challenges.

PracHub interview research ↗
What is the company culture like?

First National Bank Of Pennsylvania values professionalism, accuracy, and collaboration. You will find that the team is focused on delivering reliable results and maintaining a high standard of work.

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.