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Audience Segmentation and Cohorts Questions

Covers methods for dividing users or consumers into meaningful segments and analyzing their behavior over time using cohort analysis. Candidates should be able to choose segmentation dimensions such as demographics, acquisition channel, product usage, geography, device, or behavioral attributes, and justify those choices for a given business question. They should know how to design cohort analyses to measure retention, churn, lifetime value, and conversion funnels, and how to avoid common pitfalls such as Simpson's Paradox and survivorship bias. This topic also includes deriving behavioral insights to inform personalization, content and product strategy, marketing targeting, and persona development, as well as identifying underserved or high value segments. Expect discussion of relevant metrics, data requirements and quality considerations, approaches to visualization and interpretation, and typical tools and techniques used in analytics and experimentation to validate segment driven hypotheses.

HardTechnical
0 practiced
For cross-device segmentation you need to stitch identities while complying with GDPR/CCPA. Explain deterministic versus probabilistic identity resolution approaches, privacy-preserving alternatives (hashed identifiers, aggregation, differential privacy), and design principles to create segments that minimize storing or exposing PII while remaining useful for analysis.
HardTechnical
0 practiced
Describe a practical approach to attribute conversions and retention lift across multiple marketing channels in cohort analyses. Compare simple last-touch versus multi-touch heuristics and data-driven approaches (for example Shapley value allocation or marketing-mix models), and discuss the data requirements, assumptions, and limitations of each approach when used to inform segmentation and optimization.
MediumTechnical
0 practiced
In Python/pandas, implement (or describe implementation steps for) a function build_cohort_matrix(events_df, signup_col, event_col, period='W', periods=12) that returns a cohort retention percentage matrix (cohort_period rows, period offset columns). events_df contains user_id, signup_date (datetime), and event_date (datetime). Describe handling of missing events, NaNs, and small cohort sizes, and discuss performance considerations for larger datasets.
MediumTechnical
0 practiced
When analyzing only 'active users' you suspect selection bias compared to the full user base. Describe analytical techniques to detect selection bias (for example, comparing baseline covariates, subgroup distributions), explain how to compute and apply inverse-probability weights (IPW) in analysis, and outline a simple example where reweighting estimates population-level retention from a biased sample.
HardTechnical
0 practiced
You observe that aggregated retention increased month-over-month, but when split by device type every device shows a decline in retention. How would you investigate and resolve this Simpson's paradox? Describe the statistical checks to perform, re-weighting or stratification techniques to apply, and how you would present corrected findings to stakeholders alongside recommendations.

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