A North Star metric is the single measure that best captures the core value a product delivers to users, chosen because it tends to correlate with long-term business success; for a marketplace app this might be completed transactions rather than app downloads. You will learn the difference between leading indicators, early signals that predict future results (like weekly active users), and lagging indicators, outcomes you only see after the fact (like quarterly revenue), and why tracking both matters: leading indicators let a team react quickly, while lagging indicators confirm whether those reactions actually worked. This module also warns against vanity metrics, numbers like total registered users or page views that look impressive in a slide deck but don't reliably indicate whether the product is creating real value.