Attribution & Conversion Counting

Linear Attribution vs Position-Based Attribution

In short: Both split conversion credit across the whole path rather than handing it to one touch, and both were retired from Google Ads and GA4 reporting in 2023. Linear spreads credit evenly across every touchpoint; position-based fixes 40 percent on the first touch, 40 percent on the last, and divides the remaining 20 percent among everything in the middle. The practical split is about what the middle of a path deserves: linear treats it as equal to the ends, position-based treats it as a minor supporting role. Choose linear for an unopinionated involvement count; choose position-based when discovery and close are what your business actually cares about.

By the AdFlint research team · Fact-checked against current Google and Meta platform behavior · Last reviewed July 2026

Linear Attribution

Splits conversion credit evenly across every touchpoint in the path, so a five-touch journey gives each interaction twenty percent.

Every recorded interaction receives an identical share of the conversion, which makes long paths visible without asserting that any one step mattered more. Analysts use it as a neutral starting point when comparing channel involvement rather than channel impact. Google Ads and GA4 removed it from their reporting in 2023, though it remains standard in other analytics tools. The trap is treating equal credit as evidence of equal influence.

Full definition

Position-Based Attribution

Assigns forty percent each to the first and last touchpoints and splits the remaining twenty percent across everything in between.

Also called U-shaped, this model rewards the two moments most advertisers care about, discovery and close, while acknowledging the middle without letting it dominate. It fits multi-step B2B paths where an early content touch and a final branded search both clearly matter. Google Ads and GA4 retired it in 2023. The weakness is that the weights are arbitrary conventions, not estimates derived from how your customers actually behave.

Full definition

Side by side.

The differences that actually change what happens in your account.

	Linear Attribution	Position-Based Attribution
How the two anchor touches are weighted	No special weighting, first and last touch get the same share as every touch in between.	First and last touch are fixed at 40 percent each, always, regardless of path length.
How the middle of the path fares	Gets exactly the same credit as the ends, a path with three middle touches gives each the same slice as first and last.	Middle touches split a fixed 20 percent total, so more middle touches means each gets a smaller sliver, fast.
Sensitivity to path length	Every touch's share shrinks proportionally as the path lengthens; a ten-touch path gives each touch 10 percent.	Only the middle-touch shares shrink as the path lengthens; first and last keep 40 percent each no matter what.
What it assumes matters	Nothing in particular, it assumes every recorded touch played an equal role.	Discovery and the closing action matter most; everything else is context, not cause.
Best-fit funnel shape	Flat or unclear funnels where you do not want to bake in an assumption about which stage matters.	Clear multi-step B2B or considered-purchase funnels where an early content touch and a final branded search both plausibly earned credit.
Where it's still available	Not in Google Ads or GA4; found in third-party MTA tools or custom modeling on exported paths.	Same, dropped from Google's own reporting in 2023, still offered by outside attribution tools.
Failure mode	Overstates single-appearance channels that show up once mid-path and never again.	The 40/40/20 split is a fixed convention, not derived from your data, so it can overweight a channel just for being first or last by coincidence.

What actually separates them.

Linear recalculates every touch's share as one divided by the number of touches; position-based only recalculates the middle touches that way, while first and last stay locked at 40 percent each.

Adding a touch to the middle of a path dilutes every touch equally under linear, but under position-based it only dilutes the other middle touches, leaving the anchors untouched.

A two-touch path collapses both models toward roughly the same 50/50 split, since there is nothing left in the middle to allocate differently, the two only converge in this edge case.

Position-based always privileges whichever channel happens to appear first and last, even if that placement is coincidental, like a stray direct visit; linear has no concept of position to exploit.

Because position-based hardcodes 40/40/20, changing the number of touches never changes the ends' combined 80 percent share, whereas linear's total credit is always evenly redistributed across the full count.

Which one should you use?

Use Linear Attribution when

You want an involvement count that does not privilege any stage of the funnel over another.
Your paths are short enough that a middle barely exists, so position-based's structure adds little.
You are comparing channel mix across many campaigns and want a consistent, assumption-free baseline.
You suspect the first or last touch in your data is often coincidental, like direct visits or brand searches, rather than meaningful.

Use Position-Based Attribution when

Your funnel has a real, describable shape: an awareness channel that starts the journey and a closing channel that ends it.
You are presenting to a stakeholder who intuitively believes how we found them and what closed them matter most.
You want middle-of-funnel channels to register as supporting cast, not co-equal drivers.
You are auditing a B2B pipeline where a webinar as first touch and a demo request as last touch are the two moments the sales team actually cares about.

Common questions.

Is position-based attribution the same as U-shaped attribution?

Yes, they are the same model under two names. U-shaped describes the credit curve, high, low, high, and position-based describes how it is built. Both terms refer to the fixed 40/40/20 split across first touch, middle touches, and last touch.

Can I change the 40/40/20 split in position-based attribution?

In the tools that still offer it as a preset, no, it is a fixed convention. Some marketing analytics platforms let you build a custom weighted model where you set your own percentages, which is technically a different, configurable model even though people often still call it position-based.

Why did my reported channel mix change so much when I switched from linear to position-based?

Because position-based concentrates 80 percent of every conversion's credit onto just two touchpoints, channels that mostly show up mid-path lose a lot of ground compared to linear, where they were counted equally. If a channel's role in your funnel is genuinely middle-stage, expect its reported contribution to shrink under position-based even though nothing about its actual performance changed.

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