Thumbtack Interview Questions
Master your tech interview with our curated database of real questions from top companies.
Detail NLP preprocessing and n‑gram choices
Describe your text preprocessing pipeline given the source modality: typed text, scanned/handwritten OCR, or speech-to-text. Specify language handling...
Design cross-validation; explain bias–variance
Define cross-validation rigorously and compare k-fold, stratified k-fold, leave-one-out, nested CV, and time-series rolling/blocked CV. For a dataset ...
Choose clustering vs regression; explain KNN
When would you use clustering vs. regression on a business problem with partially labeled outcomes? Specify the decision criteria (label availability,...
Implement min, mean, median robustly
Implement three functions in Python without using numpy/pandas: (1) my_min(nums) returning the minimum in O(n) time and O(1) space; (2) my_mean(nums) ...
Compare list/dict; parse JSON/CSV at scale
Compare Python list and dict precisely: for append/insert/lookup/update/delete, state average and worst-case time complexity, memory implications, and...
Explain a project and justify choices
Walk me through your most impactful project end-to-end: what problem and success metric did you define, what alternatives did you evaluate and reject,...
Design streaming new-vs-returning monthly metrics
Streaming design: Monthly NEW vs RETURNING request shares (event-time, with late/out-of-order and duplicates) Context You receive a high-volume event ...
Optimize red-ball draw probability, prove optimality
Two-Box Ball Allocation to Maximize Probability of Drawing Red Setup - You have 2 boxes and two colors of balls. - In the 100/100 case: 100 red and 10...
Demonstrate rapid analysis and stakeholder debrief
Rapid Analysis and Stakeholder Debrief Plan You have 1 hour to analyze a provided dataset (no pre-read) followed by a 45-minute debrief with a product...
Write monthly new-vs-returning requests SQL
Given the schema and sample data below, write a single PostgreSQL query (no dynamic SQL) that returns, for every calendar month present in requests, t...
Explain power drivers and resolve unexpected A/B results
A/B Testing: Power, Sample Size, Allocation, and Diagnostics You are analyzing a two-proportion (binary conversion) A/B test with independent users, n...
Compute weekly 3-week rolling sums in SQL
Using PostgreSQL, write a single query that outputs, for each calendar week in a given range, the sum of amounts in that week and a rolling sum over t...
Lead XFN decision under tight timeline
Scenario: 72-Hour VP-Level Recommendation on Expanding a New Quoting Workflow You have 72 hours to deliver a VP-level deck recommending whether to exp...
Define success metrics for Instant Book
Instant Book: Metrics, Measurement, Rollout, and Risk Plan Context You are evaluating an "Instant Book" feature that allows customers to immediately b...
Design a robust pro-ranking A/B test
Experiment Design: Evaluating a New Pro Ranking Algorithm (Ranker) in a Two‑Sided Marketplace You are designing an experiment to evaluate a new pro ra...
Write complex joins and window functions
You are given a simplified Thumbtack-like marketplace schema in PostgreSQL. Assume UTC timestamps and weeks start on Monday. Treat "today" as 2025-09-...
Build a defensible ML pipeline end-to-end
End-to-End Binary Classification Pipeline on Tabular Data (Numeric, Categorical, Text) Context You are handed a tabular dataset that includes numerica...
Design and evaluate an A/B test for launch
A/B Test Design: New Matching Model for a Two‑Sided Marketplace Context You are testing a new matching/ranking model that determines which providers a...
Present a DS project with business impact
7-Minute Data Science Project Presentation (Onsite) Context You are interviewing for a Data Scientist role and will present a past project to a mixed ...
Implement TF–IDF with sparse matrices
Implement TF–IDF from Scratch (Python + NumPy/SciPy) You are given a list of documents (strings). Build a TF–IDF vectorizer from scratch with the foll...