Attribution models determine how conversion credit gets split among the touchpoints a user interacts with before converting. Most businesses default to last-click attribution in Google Analytics, which gives 100% credit to the final interaction, but that ignores everything that happened earlier in the journey. First-click does the opposite, crediting only the initial touchpoint. This makes sense if you're optimizing for awareness campaigns, but it undervalues the nurturing that closes deals. Linear attribution spreads credit evenly across all touchpoints, which sounds fair but treats a quick visit and a 20-minute product demo as equals. Time-decay gives more weight to interactions closer to conversion, useful for longer sales cycles where recent engagement matters more. Position-based (also called U-shaped) assigns 40% to first touch, 40% to last touch, and splits the remaining 20% among middle interactions. Data-driven attribution uses machine learning to assign credit based on actual impact, comparing conversion paths to non-conversion paths. Google Ads and GA4 offer this, but you need meaningful conversion volume (typically 3,000+ conversions in 30 days for Google Ads) to make it work. For most small to mid-market clients, the data requirements make it impractical. At Ottawa SEO, we often see clients switch from last-click to time-decay or position-based and suddenly their display and social budgets look more justified. The trick is matching the model to your actual sales process. If you're running ecommerce with impulse buys, last-click is often fine. If you're selling B2B services with 3–6 month cycles, you need something that values early research touchpoints. The real issue is that most attribution models still rely on cookies and can't track cross-device journeys or offline conversions accurately. CRA clients and professional services often close deals via phone or in-person meetings, which means even sophisticated models miss half the story. Track what you can, pick a model that reflects your customer journey, and remember the map isn't the territory.