Goldilocks influencers: Why high follower count may not be the best driver of engagement on social media

Researchers from Goethe University Frankfurt, Frankfurt School of Finance and Management, and KU Leuven published a new article in the Journal of Marketing that examines which social media influencers are most effective at turning advertising budgets into greater engagement.

The study is authored by Simone Wies, Alexander Bleier, and Alexander Edeling.

With consumers growing increasingly wary of traditional advertising, influencer marketing is gaining traction on social media platforms such as Instagram and has transformed from an ancillary tactic to a market worth more than $13 billion in 2021. Social media influencers are conspicuous in numerous online spaces, with follower counts ranging from a few thousand to many millions.

Many influencers create content that generates social media engagement, which is captured by the number of interactions with their followers (e.g., likes, comments), a highly relevant performance indicator that advertisers seek to optimize.

However, despite the growing popularity of influencer marketing, advertisers as yet do not have a solid understanding of how engagement arises, such as which influencers are most effective at turning advertising budgets into greater engagement. A main screening criterion is an influencer’s follower count, or indegree, which defines the size of the audience an influencer can directly reach.

Does a high follower count mean that an influencer will generate engagement with sponsored content? Or are small influencers best to create engagement? The new study finds that influencers with an intermediate follower count represent the engagement sweet spot.

High followers or high engagement?

Advertisers face a tricky choice. As Weis explains, “On one hand, advertisers want to leverage an influencer’s reach, which is the number of followers exposed to an influencer’s content and that, by definition, increases in indegree. On the other hand, users on social networks often seek interactive, communal relationships where they feel connected. Influencers with larger indegree often lack sufficient resources or interest to enter into meaningful, frequent interactions with their millions of followers.”

Some advertisers have identified this issue, cautioning that high indegree influencers might not be able to create significant engagement and suggesting more reliance on influencers who are not as popular.

This research digs into these views with a multimethod study based on Instagram data that includes more than 1,700 influencers across more than 800 campaigns, capturing all posts and stories as well as publicly visible and privately accessible engagement metrics. It also includes a field study with two types of experimental studies (eye-tracking and online laboratory), an add-on simulation study, and an auxiliary set of qualitative interviews.

At low to moderate follower count levels, the overall engagement between influencer and followers improves. As follower count rises, the positive effect becomes increasingly outweighed by the negative engagement likelihood effect caused by low perceived tie strength, leaving followers less motivated to engage with the influencer’s content and reducing engagement. “In short, the relationship between an influencer’s follower count and engagement follows an inverted U-shape,” says Bleier.

Content customization and sponsored posts

The research also shows that higher content customization weakens the effect of influencer indegree on engagement. This leads to small and large indegree influencers becoming more effective at generating engagement compared to medium-sized indegree influencers. Similarly, when the campaign is sponsored by a rather unknown brand, the effect of influencer indegree on engagement is less pronounced. As this relationship flattens, medium-sized indegree influencers become comparatively less effective at driving engagement.

The researchers’ work contributes to marketing research and practice in several important ways. Edeling says that “We deepen insights into the relationship between an influencer’s indegree and followers’ engagement with sponsored content. We also introduce two important campaign properties, content customization and brand familiarity, as relevant concepts to the influencer marketing literature that condition how influencer indegree drives engagement.”

Weis continues with “We highlight the peril of supersaturation effects on engagement when follower count becomes too large and show that the most effective follower count level is situated between the often-recommended very small and very large influencer tiers. At the same time, advertisers and influencers also have room to maneuver in that brands that allow influencers to promote content independently and brands that are less known observe a weaker inverted U-shaped relationship between follower count and engagement, reducing the pressure for them to collaborate with medium-sized influencers who have an optimal number of followers.”

The study offers the following advice for advertising managers to improve their influencer marketing strategies:

• Brands should empower influencers with a large following to create original content in their own style instead of repeating the brand’s official communications.
• To maximize engagement, well-known, mainstream brands should contract with influencers with neither too few nor too many followers.
• Influencers with large follower counts might consider expanding their partnerships with lesser-known brands to enjoy mutual benefits.