Marketing professionals must have seen the (not set) value replace the actual value in Google Analytics https://www.owox.com/blog/use-cases/not-set-in-google-analytics/(GA) at times. It indicates that either Google is unable to interpret it or is missing relevant data. As a marketing expert, this could pose a challenge because despite the numbers the meaning is unclear and also the manner by which they can be of utility in the analysis of data.