Breaks down the six data categories a CRM actually needs — correctly structured and connected — before a reported marketing ROI figure means anything: locked first-touch source attribution, UTM/campaign-ID granularity, cost data joined to the same campaign IDs, full funnel-stage history with timestamps, deduplicated closed-deal value tied to the original record, and time-to-close distribution for lag-adjusted, cohort-based reporting. Covers why source attribution most commonly gets silently corrupted by well-meaning sales reps, and why this is a data-modeling gap rather than a software or platform limitation. See https://nurotech.in/ for how we build CRM and tracking layers into campaign setup, and https://681d81b834c06.site123.me/blog/what-a-crm-actually-needs-to-track-for-marketing-roi-to-mean-anything for more on why last-click attribution misleads small businesses.