A recent study by Schlesinger Associates for Augure found that 75% of marketers consider finding the right influencers the most challenging aspect of an influencer marketing strategy. Perhaps that’s due to a misguided approach in which the size of someone’s following is treated as the primary benchmark of their influence.

New research shows that you only need handful of influencers to give the impression that everyone is talking about your brand.

Researchers at the University of Southern California recently uncovered the majority illusion, a paradox within social networks that makes some ideas, behaviors, or attributes appear widespread even when they are not. Since we can’t keep an eye on what the entire world is up to, we’re limited to witnessing what our social network says and does. At times, well-connected members within our network can skew our perception of how common an idea or behavior actually is.

When it looks like an idea or action is much more popular than it is, it greatly increases the likelihood that others will adopt it too. In other words, the majority illusion may be a driving force behind why something eventually becomes truly popular. For example, one of the study’s researchers, Kristina Lerman, believes the majority illusion was a factor in the Arab Spring gaining momentum and the shift in public opinion toward same-sex marriage.

And yet under insidious applications, the majority illusion can even cause people to adopt false beliefs or extreme viewpoints without realizing they are rare, which helps explain how fringe political and ideological groups may develop.

Beyond explaining why uncommon beliefs can appear far more popular than they actually are, the majority illusion also explains something we already know – influence depends heavily on having the right connections. But in addition to being well-connected, an individual’s location within a network plays a role in their potential to create the majority illusion.

In the diagram above, the red nodes are “active,” meaning they all share an attribute, such as being a redhead or following a vegan diet. The network structures in both figures are identical, yet the placement of active members differs. Figure A illustrates how a few well-connected people can cause the majority illusion; a large fraction of the network will observe the active attribute in their neighbors, which can give the impression that a lot more people are redheads or vegans than is globally true. While in figure B, the group members won’t perceive an abundance of redheads and vegans since they aren’t observing as many people in their network with those attributes.

Visualizing the hierarchical relationships within a social network further demonstrates how the structure of the network, and the specific location and connections of certain influencers, makes some people more influential than others, even when they have fewer followers.

If that sounds a bit complicated, stay with me.

My team at Fractl created the below influencer marketing network graph using 77 mid-level Twitter influencers (between 30,000 and 500,000 followers) across eight different verticals to illustrate strategic positioning among influential accounts.

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In the graph, each node represents an influencer and the lines between nodes represent a relationship. The bigger the node, the more connections that influencer has within this particular network – it does not mean they have the largest following overall. Each color represents which vertical an influencer belongs to. As you can see, the larger nodes often have connections across multiple verticals. Again, these are not necessarily the most “popular” influencers with the largest following.

As our graph shows, being well-connected or strategically positioned within a social network may impact one’s ability to influence others more than the size of one’s following. That’s not to say that size never matters — individuals with bigger networks do tend to more influential. But the structure of those connections matters, too. So marketers should focus on two other factors that measure influence in a social network: “betweenness centrality” and closeness.

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“Betweenness centrality” is a person’s location between different sections of a network. A high betweenness centrality signals a strategic position. For example, consider an executive with connections throughout several industries, as opposed to a leader who is only well-connected within his own industry.

Closeness is the average number of degrees between an individual and other members of the network; someone with one degree of separation, or more closeness, will probably wield greater influence (consider the ease of getting a favor from a friend as opposed to a friend of a friend’s mother’s cousin).

Influencers who have a high betweenness centrality are ideal for reaching a wide audience, while influencers within a tightly-knit niche group are best suited for action-driven goals.

Want to quickly get the word out about a new product? Get a handful of influencers with high betweenness centrality talking about it. Potential reach is greatest among these strategically-positioned influencers since their connections across various networks help them efficiently disseminate information. Ann Handley (@MarketingProfs) and Daniel Pink (@DanielPink) are two great examples from our network graph with high betweenness centrality (8.71 and 7.72, respectively). Notice how their connections span across the entire graph.

Want to get people to take action, such as signing up for a free trial or sharing a video? The researchers found the majority illusion is most likely to occur when group members with a low number of connections have a tendency to connect with individuals with a lot of connections. In networks where members have a low degree of connections, exposure to outside ideas and opinions is limited, making them more easily influenced. The high-degree members of these close-knit networks, who we’ll call niche leaders, have great influence within their network, making them an ideal partner for accomplishing conversion-driven goals.

In the graph, you’ll notice isolated groups on the edges of the graph. The example below shows one such group, a cluster of individuals in the “public health” community that with few connections to the other verticals in the network. Most of this cluster is connected to one or two larger nodes which are probably niche leaders.

As Malcolm Gladwell said in The Tipping Point, “There are exceptional people out there capable of starting epidemics. All you have to do is find them.” Fortunately, you don’t need to build a network graph model to locate influencers with the highest potential to create the majority illusion.

To find influencers with high betweenness centrality, look for people followed by other influencers who also have followers across many verticals. It helps if their niche naturally overlaps with other niches (such as a travel journalist followed by business professionals in a range of industries). To find niche leaders, look for people with narrowly-focused interests whose followers are similar to them but have a low number of followers.

Lastly, timing is a key factor for creating the majority illusion. Coordinate a handful of influencers to push your message, product, or content around the same time to give the impression that “everyone” is talking about your brand.