What is lead source attribution?
Lead source attribution is how you record the channel that first brought a lead into your CRM, and how you credit the later touches that helped it convert.
Two views are useful. Original source records where the lead first came from and should not change once set. Influence records the later touches, such as nurture emails, events, and sales outreach, so credit can follow the activity that moved the buyer.
Problems start when the source field gets overwritten. Marketing and Sales then each credit themselves, and reports disagree. Define the rules in writing, keep the original source fixed, and log touches separately.
It affects CAC because credit decides which channel the wins are attributed to. Wrong credit leads to cutting spend that worked and funding spend that only looks effective.