Last Click Continues to Undervalue Paid Social in 2024, and Fospha Reveals a ‘Halo Effect’ for TikTok.

It’s no secret that Paid Social is a major driver of performance for eCommerce brands, despite what Last Click measurement might show. 
At Fospha, we wanted to reflect on how severely the largest Paid Social channels – Meta and TikTok – were impacted by Last Click attribution in Q1 2024.  
We also took a deeper look at TikTok – the most undervalued of the top-spend channels when using Last Click measurement, uncovering that the bottom-of-funnel significantly benefits from its halo effect’. 

Why this research matters 

Fospha data shows that Paid Social is significantly under-invested, with brands on average only reaching 41% of its potential. Last Click measurement exacerbates this problem. Where brands can’t see impact, they won’t invest – leaving millions of $$ on the table. 

Who are Fospha? 

Fospha is the marketing measurement platform for eCommerce, using multi-touch attribution and marketing mix modelling to reveal the impact of both clicks and impressions on driving sales. Its impressions modelling also addresses misattribution caused by iOS14, enabling accurate attribution of Paid Social channels. 

Meta drove 226% more conversions in Q1 than Last Click claims 

Meta is the most scaled Paid Social channel, making up 49% of the average brand’s mix. This means misattributing Meta can significantly hinder a brand’s revenue potential. 

In Q1, Meta was heavily undervalued by Last Click. This impact is even more severely felt when segmenting just for Awareness and Consideration activity, with Fospha revealing that 101X more conversions were driven from the higher funnel than Last Click claims. 
Fospha data shows that investing in upper funnel is vital for long-term resilience – with the best optimized brands from a CPA perspective spending 18%+ in Awareness & Consideration in Meta. But for brands relying on Last Click, it becomes challenging to justify this investment. 

TikTok drove 788% more conversions in Q1 than Last Click claims

TikTok is becoming an increasingly prominent channel in brand’s channel mixes, now comprising 10% of the average brand’s mix.

Last Click undervalues TikTok to an even greater extent. This supports our earlier findings, which examined Q4 2023. These revealed TikTok as the most undervalued of the large-spend channels.

It’s therefore clear that this trend continues through to 2024. Just like Meta, TikTok’s higher funnel is even more neglected – with Awareness & Consideration driving a collosal 702X more conversions than Last Click claims. 
With TikTok being so heavily under-valued – this led us to the next phase of our research. We hypothesised that these conversions belonging to TikTok are being artificially credited to the bottom-of-funnel (Natural Search, Direct, Brand PPC).

We dove under the hood to investigate a potential TikTok ‘halo effect’. For this portion of the research, we expanded our analysis to the date range January 2023-April 2024.

TikTok creates a halo effect, driving 22% of sales credited to bottom-of-funnel (US dataset)

Our research uncovered that of the conversion credit that is being attributed to bottom-of-funnel, 22% belongs to TikTok. Brands relying on Last Click to measure TikTok are therefore likely to see low performance for TikTok, and inflated performance for Natural Search, Direct and Brand – which is not reflective of reality.

Direct benefits the most from TikTok’s influence

Fospha data shows that of all channels that are boosted in platforms like GA by TikTok ads, Direct benefits most, cannibalising 44% of TikTok’s sales.

This creates insight into the customer journey. TikTok acts as an initial touchpoint in the customer journey, sparking interest. However, Last Click attribution credits Direct for sales, as users often visit the brand's website some time after engaging with TikTok content.

There were also differences found by funnel stage within TikTok ads. Performance campaigns had a greater influence on Organic Search, whereas Brand campaigns were more likely to drive users towards eventually checking out via Direct and Brand PPC.

Last click credits TikTok slightly more in the US – but privacy regulation threatens this visibility further

In the US, where privacy legislation is a few years behind Europe, Last Click is able to pick up more of the value of TikTok than in Europe. However, the amount of credit TikTok receives is still incredibly low relative to its total impact (just 8%). Regulation and consumer behavior around privacy in North America is also quickly catching up with Europe, so we expect to see this degrade further over the next few years. More measurement challenges are promised to come for brands who do not adopt next generation measurement.


Misattributing Meta and TikTok’s impact not only leads to missed revenue potential but also perpetuates a cycle of underinvestment in Paid Social – especially the higher funnel.

Fospha’s analysis reveals TikTok’s pivotal role in driving eCommerce sales. Last Click attribution disproportionately benefits Direct, Organic Search, and Brand Search over all Paid Social channels, but it particularly masks the role that higher-funnel channels like TikTok play.

Fospha's mission is to empower brands with the tools needed to make informed decisions, ensuring they maximize the value of every marketing dollar spent.

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