K-factor (marketing)

In viral marketing, the K-factor can be used to describe the growth rate of websites, apps, or a customer base. The formula is roughly as follows:[1]

${\displaystyle i={\text{number of invites sent by each customer }}}$ (e.g. if each new customer invites five friends, i = 5)

${\displaystyle c={\text{percent conversion of each invite }}}$ (e.g. if one in five invitees convert to new users, c = .2)

${\displaystyle k=i*c}$

This usage is borrowed from the basic reproduction number in the medical field of epidemiology in which a virus having a k-factor of 1 is in a "steady" state of neither growth nor decline, while a k-factor greater than 1 indicates exponential growth and a k-factor less than 1 indicates exponential decline. The k-factor in this context is itself a product of the rates of distribution and infection for an app (or virus). "Distribution" (i) measures the average number of people a host will contact while still infectious, and "infection" (c) measures how likely an average person is to also become infected after contact with a viral host.[2]

Social K-factor Defined

With the advent of social media, a new evolution to the K-factor concept has emerged. The Social K-factor is an indicator of how viral a website is when content is shared from the website onto social media. It is a function of the Social Coefficient, which determines how fast content is spreading through social sharing, and the Sharing Ratio, a measure of how often your content is likely to be shared. [3]

As visitors to your website share your website's content on their social networks, the content can go viral because the social media posts attract new visitors who then share more content. The Social K-factor measures the lift delivered from social sharing. [4]