Search volume is a factor in calculating visibility in Moz. Moz's "Visibility Score" takes into account both keyword rankings and search volume for those keywords.

The Visibility Score is a metric that measures how visible a website or webpage is in search engine results pages (SERPs) for a given set of keywords. Moz calculates the Visibility Score by analyzing the rankings of a website's keywords and multiplying them by the estimated monthly search volume for each keyword.

So, while keyword rankings are an important factor, search volume is also taken into consideration when calculating the Visibility Score in Moz. This means that a website's visibility in Moz is influenced not only by its ability to rank highly for keywords, but also by the popularity and search volume of those keywords.