What is attribution modelling and why is it hard?
Interviewer Expectations for this Question
01
Core Competency
Assesses fundamental understanding of Data Analysis & BI conventions, runtime behavior, and memory/performance considerations.
02
Evaluation Criteria
Hiring managers look for precision, avoidance of ambiguous jargon, and ability to explain trade-offs under real production conditions.
Comprehensive Model Answer
Verified Solution
Attribution assigns credit for a conversion to the marketing touchpoints along the customer journey. The model choice changes how budget is allocated.
Common models:
- Last click: simple, overcredits closing channels such as branded search.
- First click: credits awareness, ignores nurturing.
- Linear: equal credit across touchpoints.
- Time decay: more credit to recent touches.
- Position based: weights first and last.
- Data driven: Shapley values or Markov chains estimate each channel's marginal contribution.
SELECT conversion_id, MAX_BY(channel, touch_time) AS channel
FROM touchpoints GROUP BY conversion_id;
Challenges include cross-device and offline journeys, view-through impressions, and correlation between channels. None of these models proves causality; incremental lift requires experiments or geo holdouts. Use attribution for directional budgeting and experiments for causal truth.
Candidate Response Strategy & Interview Tips
- Start with a concise one-sentence summary: Deliver a direct, confident answer first before expanding into nuances.
- Demonstrate real-world trade-offs: Discuss where this approach excels and when you would avoid it in production systems.
- Discuss complexity & edge cases: Proactively explain time/space complexity or boundary conditions (null values, scale limits).
- Prepare for interviewer follow-ups: Technical hiring panels frequently probe deeper into concurrency, backward compatibility, or alternative libraries.