Beyond Engagement: Why Influencer Marketing Can Underperform for Brands

Executive overview

An influencer campaign can attract attention without delivering an acceptable commercial return. Views, likes and comments describe audience activity. They do not, on their own, establish incremental sales, profitable customer acquisition or long-term customer value.

Yet the evidence does not support a blanket conclusion that influencer marketing fails. Published research identifies positive effects alongside important differences between campaign objectives, audiences, content and influencer characteristics.

NYBACS's position is that influencer marketing should face the same commercial discipline as other marketing investments: a defined objective, appropriate measurement, complete cost accounting and a clear decision rule for continued spending.

This review examines where performance evaluation can go wrong and provides a framework for brands assessing their next campaign.

What published research tells us

A meta-analysis by Pan and colleagues synthesized 1,531 effect sizes from 251 papers. It distinguishes non-transactional outcomes, including attitudes and purchase intentions, from transactional outcomes such as purchase behaviour and sales. The factors associated with effectiveness differ across these outcomes.[1]

That distinction matters commercially. A campaign that improves purchase intention has not necessarily demonstrated profitable sales.

Research by Leung and colleagues finds that effectiveness depends on influencer, audience and content characteristics. Several relationships are nonlinear, suggesting that simply maximizing posting frequency, audience fit or promotional positivity is not a reliable universal strategy.[2]

A further meta-analysis covering 71 papers and 135 experimental studies reports positive effects on engagement and purchase intention, with results varying by influencer size and other conditions.[3]

Taken together, these studies support a conditional conclusion: influencer marketing can work, but success depends on the objective, execution and outcome being measured.

Where engagement and commercial outcomes diverge

Campaign reporting becomes misleading when the metric presented as success differs from the objective used to authorize the budget. For an awareness campaign, relevant reach and measured changes in awareness may be appropriate outcomes. For a sales campaign, engagement alone is insufficient.

Supporting indicators help explain performance. They should not silently replace the agreed commercial objective.

Attribution does not automatically establish causation

Tracking links, promotional codes and platform reports help identify transactions associated with a campaign. They do not necessarily show which purchases would have occurred without it.

A customer may encounter several channels before buying. A promotional code may be used by an existing customer who already intended to purchase. Conversely, an influencer may introduce a product that is purchased later through an untracked route.

NYBACS recommends distinguishing three measures:

• Attributed sales: transactions credited to a campaign under a defined tracking method.
• Incremental sales: transactions estimated to have occurred because of the campaign.
• Incremental contribution: the contribution from those additional sales after relevant variable costs.

Where feasible, brands should use carefully designed comparison groups or controlled tests. Where these are impractical, reporting should acknowledge uncertainty rather than present attribution as proof of incrementality.

Smaller influencers are not automatically cheaper to manage

An individual creator's fee is only one component of campaign cost. Managing multiple creators can require additional sourcing, vetting, contracting, briefing, approvals, payment administration and reporting. Whether these costs outweigh the benefits is a question for the brand's actual records.

The relevant comparison is the total cost of delivering the desired outcome, not the quoted fee per post.

Reusable content may create additional value. That value should be identified separately and assessed against the rights actually obtained.

Diagnose declining performance before assigning a cause

When performance deteriorates, audience fatigue is one possible explanation. Other possibilities include changes in pricing, availability, creative quality, platform distribution, competitive activity or the website's conversion process.

A brand should examine the sequence: did relevant reach fall, did audience response fall, did qualified traffic fall, or did the purchase conversion rate fall?

Each pattern calls for a different response. Replacing the influencer may achieve little if the main problem is stock availability or checkout friction. Interviewees' explanations can help identify hypotheses; they do not independently establish the cause of a decline.

A practical break even calculation

The following is an illustrative calculation, not a survey finding or participant case.

• Total campaign cost: US$12,000
• Contribution per incremental order before campaign costs: US$30
• Estimated incremental orders: 300

Break-even volume is US$12,000 ÷ US$30 = 400 incremental orders.

At 300 incremental orders, the campaign produces US$9,000 of contribution before campaign costs, leaving a US$3,000 shortfall.

If tracking tools credit the campaign with more than 300 orders, that alone does not change the calculation. The conclusion depends on how many orders were genuinely additional. This simplified example excludes future repeat purchases and separately valued content assets. Include those benefits only under clearly stated, supportable assumptions.

The NYBACS campaign review framework

Before approving or renewing an influencer campaign, management should answer six questions:

1. Objective: What specific business outcome are we purchasing?
2. Audience: Does the creator reach customers who can realistically buy our offering?
3. Measurement: How will we distinguish campaign-associated activity from incremental results?
4. Economics: What is the complete campaign cost and break-even requirement?
5. Execution: Are deliverables, usage rights, timelines and reporting responsibilities documented?
6. Decision: What evidence will lead us to expand, revise or stop the campaign?

The purpose is to make budget decisions repeatable and defensible.

Questions for a brand evaluation survey

The following instrument can support future research or internal campaign reviews. It is a proposed framework, not a statement that these exact questions were used in earlier interviews.

1. What was the primary objective of your most recently completed influencer campaign?
2. What was the total campaign cost, including creator fees and internal management?
3. What measurable target was agreed before launch?
4. What result was achieved, over what period, and according to which records?
5. Which methods were used to attribute transactions or enquiries?
6. Was a comparison group or another incremental-impact method used?
7. How were audience relevance and engagement authenticity assessed?
8. How many staff hours were required to administer the campaign?
9. Did results change relative to a comparable earlier campaign, and what other conditions changed?
10. Would you increase, maintain, reduce or discontinue spending, and why?

For publication, each statistic should identify its answering population and response count. Brand-level results should consolidate multiple respondents under a documented rule. Questions answered only by CEOs or marketing heads require separate subgroup denominators.

Conclusion

Influencer marketing deserves neither automatic rejection nor automatic renewal. The commercial question is whether a campaign delivers its intended outcome at an acceptable total cost.

Brands are better positioned to answer that question when they separate attention from transactions, attribution from incrementality, and creator fees from full programme costs.

NYBACS advocates evaluating influencer marketing as a measurable business investment, with explicit assumptions and accountable spending decisions.