GA4 model comparison report
The GA4 model comparison report (under Advertising > Attribution) places two attribution models next to each other for the same conversion events, exposing how much credit each channel gains or loses when you change the rule. It does not change billing or optimization — it is a diagnostic to understand model sensitivity before acting.
What the report does
Model comparison sits in GA4's Advertising workspace. You pick a conversion event, a date range, and two models — for example data-driven vs last click. GA4 then shows credited conversions and revenue per channel under each model, plus the percentage change.
Nothing about the underlying events changes; the report only redistributes the same conversions according to two rule sets so you can see the delta.
How to read the delta
Channels that rise under data-driven and fall under last-click are typically assist or awareness channels. Channels that fall under data-driven are often last-touch closers (branded search, direct) that single-touch rules over-reward.
The comparison is a sensitivity check: if budget decisions flip depending on which model you pick, that channel needs an incrementality test, not just a model swap.
- Pick one conversion event and a fixed date range
- Compare two models; read per-channel percent change
- Big swings flag rule-sensitive, often upper-funnel channels
How it appears in analytics and logs
Large swings between models for one channel mean that channel's credit is highly rule-dependent — usually an upper-funnel or assist-heavy channel that single-touch rules undervalue.
Diagnostic use case
Compare data-driven against last-click for the same date range to see which channels are over- or under-credited by a single-touch rule before reallocating budget.
What WebmasterID can help detect
WebmasterID records first-party conversion events you can read independently of any platform's model, giving a stable observed baseline to sanity-check GA4 model swings.
Common mistakes
- Treating the comparison as proof one model is 'correct'.
- Comparing across different date ranges or conversion events.
- Skipping an incrementality test when budget calls flip by model.
Privacy and accuracy notes
The report reads aggregated, modeled conversion credit; it is educational, not a billing source of truth. Treat model choice as analysis, not legal advice.
Related pages
- Data-driven attribution: promise and caveats
Data-driven attribution (DDA) assigns credit using a model trained on a site's own conversion paths rather than a fixed rule like last-click. Done well it credits assist touches more fairly. Its caveats are real: it needs enough conversion volume, it is a model not a measurement, and it cannot see touches that were never tracked.
- GA4 conversion paths report
The GA4 conversion paths report (Advertising > Attribution > Conversion paths) lists the channel sequences users followed before converting and splits data-driven credit across early, middle, and late positions of those paths. It answers 'what touched users before they converted, and in what order?' — turning multi-touch theory into an inspectable table rather than a single last-click number.
- Attribution in GA4
Google Analytics 4 (GA4) implements attribution with a data-driven model as the default for its conversion reporting, plus rules-based options, configurable lookback windows, and default channel groupings. It also distinguishes attribution used in GA4 reports from the conversions Google Ads counts. This page describes GA4's attribution posture and the settings that change how credit appears.
- Attribution analytics
Read conversion credit across channels first-party.
Sources and verification notes
- Google Analytics Help — Model comparisonDocuments the model comparison report and supported models.
Last reviewed 2026-06-24. Facts are checked against primary/official sources where available; uncertain specifics are marked “Data not yet verified” rather than guessed.