I have been working on a Junior Data Analyst vacancy and received over 2,000 applications. To speed up the screening process and better assess candidates’ SQL capabilities, we introduced a technical take-home challenge as an initial step, prior to any verbal contact with the hiring team.
The pass-through rate for candidates with 6 months to 2.5 years of experience (salary range £35k–£45k) was 27%, which was significantly lower than anticipated. Based on this, we implemented the following interview structure:
- Format: Short SQL/data take-home challenge (approximately 45 minutes of expected effort). Candidates have one week to submit.
- Delivery: Hosted via a coding assessment platform (link provided to applicants). No real company PII or sensitive datasets are included; all data referenced in this repository is synthetic.
- Candidate guidance: Applicants receive the challenge link, a short dataset description, expected outputs and sample rows, along with an honesty and AI-usage statement.
- Assessment focus: SQL correctness, query efficiency, explanation of approach, edge-case handling, and clarity of assumptions.
- Outcome: Candidates who meet the required technical standard progress to the interview stage.
- Structure:
- 5 minutes — Introductions and role context
- 45 minutes — Competency-based questions and discussion of the take-home challenge (including trade-offs and optimisation choices)
- 10 minutes — Candidate questions
- Scorecard (example weighting):
- Communication
- Alignment to role
- Stakeholder experience
- Cultural fit
- Structure:
- 10 minutes — Candidate experience of the process and motivation
- 30 minutes — Competency-based questions mapped to company values
- 5 minutes — Candidate questions
- Scorecard (example weighting):
- Autonomy
- Learning speed
- Trust building
- Collaboration
- Craft and quality
#interview-prep
Notes
- All datasets referenced in this repository are fully synthetic and safe for external use.
- No personal, candidate, or sensitive company data should be uploaded to or stored in this repository.
- This document provides a high-level public overview; detailed operational materials are maintained separately.