Define success metrics for Messaging serving job seekers at global scale

Problem Statement Description

Product context: LinkedIn is Microsoft's professional network; its products include profiles, feed, jobs, recruiting, LinkedIn Learning, sales tools, messaging, and ads.

LinkedIn Messaging is a core communication channel for job seekers who need to connect with recruiters, hiring managers, referrals, career advisors, and professional contacts across markets. In this interview, you are asked to define how success should be measured for Messaging specifically when it serves job seekers at global scale.

Focus on the end-to-end job-seeker communication journey: discovering whom to contact, initiating or receiving messages, understanding relevance, responding in time, managing conversations, and progressing toward meaningful career outcomes. The metric framework should account for both immediate messaging behavior and longer-term professional outcomes without assuming that more messages are always better.

Because LinkedIn operates a trusted professional network, the measurement approach should balance job-seeker value with recruiter experience, message quality, safety, privacy, deliverability, and global differences in hiring norms. Your answer should make clear what the primary success metric is, how it is defined, and how supporting and guardrail metrics help interpret performance.

The experience should consider:

- The exact user segment and denominator: active job seekers, open-to-work members, applicants, passive candidates, new graduates, career switchers, or market-specific cohorts.

- Core messaging funnel instrumentation: message exposure, send, delivery, open, reply, conversation continuation, and downstream hiring-related actions.

- Quality and outcome metrics that distinguish useful professional conversations from spam, low-intent outreach, or superficial engagement.

- Cohort cuts by geography, language, device, job type, seniority, industry, recruiter versus peer conversations, and first-time versus repeat job seekers.

- Guardrails for trust, safety, notification fatigue, unwanted messages, response pressure, blocking/reporting, and recruiter-side degradation.

- Attribution challenges between Messaging and other LinkedIn surfaces such as Jobs, profile views, recruiter search, recommendations, and notifications.

- Decision usefulness: how the metrics would guide product prioritization, experimentation, marketplace health, and long-term job-seeker value.

The goal is to present a rigorous, globally scalable success-measurement framework for LinkedIn Messaging that captures whether job seekers are having timely, trusted, and career-relevant conversations, while preserving the health of the broader professional network.