KPIs in Influencer Marketing: how to evaluate influencers and campaign results

Evaluating the performance of an Influencer Marketing campaign - whether in real time or after it concludes - is always a sensitive issue.

Difficulties in tracking conversions, calculating ROI, and other aspects still hinder the ability to realistically assess the impact of an influencer marketing campaign.

At Inflead, we believe that data is essential in order to define a strategy with a clear understanding of the expected results and where to focus efforts.

In this article, we aim to clarify things by analyzing the most important KPIs in the world of Influencer Marketing and exploring some lesser-known metrics that can make a big difference in the success of your strategy.

Influencer Marketing KPIs: what they are and which ones to track

In general terms, KPI stands for Key Performance Indicator, a quantitative measure used to assess the success of an activity in relation to specific goals.

In marketing, KPIs are metrics that allow us to monitor and evaluate the performance of any type of activity, such as website visits, conversion rates, social media engagement, and more.

Each strategy should naturally include a set of KPIs that reflects business goals and the type of activity being undertaken. For instance, a lead conversion strategy aimed at turning contacts into customers cannot be evaluated with the same parameters used for a brand awareness campaign, which instead seeks to strengthen brand visibility and recognition.

Focusing specifically on influencer marketing, let’s now explore both the classic KPIs in this field as well as some more specific and targeted ones.

The KPIs covered in this article are:

Followers and Audience
Reach
Impressions
Engagement Rate
Return On Investment

Basic metrics: Followers and Audience

When choosing a creator for your strategy, followers and audience are typically the foundation of influencer marketing.

Followers: - the users who follow a specific profile on a social platform - are a clear indicator of an influencer’s popularity and the potential audience that can be reached. When a social media account has a large number of followers, it generally means the content resonates with a specific audience. This resonance not only amplifies the message but also increases the chances of higher engagement rates.

It goes without saying, the more followers a profile has, the greater the chances that an Influencer Marketing campaign will have a significant impact. However, it’s not uncommon for creators - especially those with smaller followings - to “game the system” by inflating follower and engagement numbers to grow faster. Therefore, it’s important during the evaluation phase to access information that clearly indicates whether a profile is “healthy” or relying on dishonest practices.

The audience of an influencer refers to the group of people who actually interact with their content. It’s a key indicator of a campaign’s success. This measure reflects not only how many people see an influencer's posts but also how effective they are at engaging and capturing viewers’ interest. If content goes viral, the audience may exceed the influencer's regular follower count. Understanding an influencer’s audience is crucial for tailoring marketing strategies and maximizing the impact of promotional campaigns.

Reach

The reach KPI measures the number of unique users who have been exposed to a specific piece of content.

So, reach represents:

the potential scope of a message or campaign;
the total number of unique individuals who saw the content during a specific time frame.

This KPI is directly linked to the audience and provides critical insight into the spread of the message. Measuring reach helps assess the impact and visibility of a marketing campaign and allows for strategic adjustments based on audience reach and brand awareness goals.

Impressions

Impressions is another KPI that gauges content visibility and exposure. It indicates the total number of times a piece of content was displayed to potential viewers across various channels (social media, websites, ads, etc.).

Impressions are counted every time content appears on a device screen - regardless of whether the user interacts with it or has seen it before. This KPI indicates the potential audience reached by a campaign or piece of content, helping evaluate how effectively it’s been distributed.

Reach vs Impressions

What’s the difference between reach and impressions? Reach measures the number of unique users who view content, whereas impressions count how many times the content appears in total - even if the same user sees it multiple times.

In practice: the first time a user sees a campaign ad, it counts as both a reach and an impression. Each subsequent time that same user scrolls past the same ad, it will count only as an additional impression.

Engagement Rate

Engagement Rate is one of the most important KPIs in influencer marketing. It reflects the level of interaction and involvement generated by a piece of content in relation to the total number of users who viewed it.

It’s essentially a ratio between reach and interactions, allowing you to measure an influencer’s ability to move their audience and build meaningful connections with followers. The higher the engagement rate, the more involved and active the audience is in the creator’s content.

Engagement rate is also a litmus test for the actual impact of marketing campaigns on the target audience, and it often indicates a strong connection between the influencer, the brand, and the audience.

ROI – Return On Investment

Return On Investment (ROI) is a critical KPI for assessing the real effectiveness of a campaign, as it measures the relationship between the cost of the campaign and the revenue it generates.

A positive ROI indicates that the marketing activities are yielding profits, while a negative ROI means the campaigns are underperforming.

By monitoring ROI, you can identify areas for improvement, make informed decisions about investments, and maximize performance. ROI can also be broken down into specific areas, offering insights into individual campaign components.

Advanced KPIs to scale Influencer Marketing strategy

All the KPIs discussed so far pertain to post-campaign analysis—or at best, real-time analysis if tools are available.

However, a good influencer marketing strategy is clearly prepared in advance with specific goals in mind. So how can we identify the most suitable influencers ahead of time, make accurate performance predictions, and scale the strategy?

Thanks to Italy’s first quality certification algorithm for creators, at Inflead we’ve developed a series of evaluation metrics that, when analyzed together, can predict expected campaign performance in collaboration with an influencer.

These are advanced insights that help brands, agencies, and media centers identify the content creators best aligned with their goals. Specifically, we’re talking about:

Influencing Value
Efficiency
Estimated Earned Media Value
Sponsored Influencing Value & Sponsored Efficiency
Engagement Rate & Story Engagement

Let’s examine these KPIs one by one and how they can help scale your influencer marketing strategy.

Influencing Value

This is Inflead’s key metric, designed to measure the real reach of a profile - that is, the number of real users that an influencer can effectively influence through their content.

Main inputs to estimate this value include:

engagement rate;
posting frequency and consistency;
engagement distribution;
audience impact;
attractiveness;
interactions with suspicious profiles;
membership in POD groups (users who coordinate to artificially boost followers and engagement).

This metric provides an absolute estimate of how many people a profile can truly influence.

Efficiency

This is the ratio between Influencing value and Number of followers. It shows the percentage of followers a profile can truly reach.

This is especially useful for comparing influencers, even if they have very different follower counts, by evaluating the relative effectiveness of each.

Estimated Earned Media Value

This output estimates the cost of reaching, through paid ads, a number of users with similar interests and demographics to those a creator could reach organically via collaboration. To calculate it, the necessary inputs are socio-demographic data from the profile’s audience, the Influencing Value, and the average CPM on the relevant platform.

This value doesn’t factor in the creator’s effort to produce content or their personal branding, but it’s a valuable benchmark for marketers to assess a creator’s effectiveness and the estimated investment needed to achieve similar results through paid ads.

Engagement Rate & Story Engagement

The Engagement Rate measures the percentage of users who interact with a creator’s posts on average, calculated from their last 20 posts.

Story Engagement measures the average percentage of followers who view the creator’s stories.

Which KPIs should you measure in Influencer Marketing?

It’s often said that marketing isn’t an exact science - and that’s true. But it’s equally true that the more relevant data you have, the more likely you are to craft an effective strategy.

Choosing the right KPIs for selecting a creator or evaluating a campaign depends above all on your strategic goals. ROI is often the go-to metric, and rightly so - but not every influencer marketing campaign is designed to generate immediate ROI.

What really matters is having access to the right data that allows you to optimize and scale your strategy. That’s why at Inflead we’ve devoted all our efforts to generating unique, accurate, and predictive insights into creators and campaigns.

You can now test this data for 14 days with our free trial. Activate it: