Define success metrics for Music serving free listeners

Problem Statement Description

Product context: Spotify is an audio streaming company; its products include music, podcasts, audiobooks, playlists, recommendations, creator tools, subscriptions, and ads.

Spotify’s Music experience serves a large global base of free listeners who can stream music with advertising and product limitations compared with paid subscribers. In this interview, you are being asked to define what “success” means for that free-listener music experience, not to redesign the product or propose a growth strategy.

Focus on the end-to-end listener journey: opening Spotify, finding something to play, listening through sessions, encountering ads or free-tier constraints, discovering new music, returning over time, and potentially deepening engagement with Spotify’s ecosystem. The metrics should help Spotify understand whether the free music product is valuable to listeners, sustainable for the business, and healthy for artists, advertisers, and the broader platform.

Your answer should be specific enough that a product team could use the metrics to monitor performance, compare cohorts, diagnose trade-offs, and make product decisions for the free music tier across markets and listener types.

The experience should consider:

- Clear definition of the primary success metric and why it reflects value for free music listeners.

- Denominators and eligibility rules, such as active free listeners, new free users, ad-supported music users, or session-level populations.

- Supporting metrics across engagement, retention, discovery, monetization, and listener satisfaction.

- Instrumentation needs for playback, search, recommendations, skips, session starts, ad exposure, ad completion, and tier status.

- Cohort cuts such as new vs. existing users, geography, device type, music genre preference, acquisition source, and ad load exposure.

- Guardrail metrics that prevent optimizing one area at the expense of user trust, creator outcomes, advertiser value, or Premium conversion.

- How the metrics would be used to evaluate product changes, diagnose declines, and distinguish healthy engagement from low-quality usage.

The goal is to define a practical, decision-useful metrics framework for Spotify’s free music experience that balances listener value, long-term retention, advertising monetization, discovery, and platform health.