How to Measure the Impact of Customer Stories

So, how do you go about measuring the impact of customer story or the return on investment and should we be looking at that for one specific type of content in the first place? And this is the hard question is how do we know it's working. I think we want to look at metrics surrounding things like time on site or they actually consume in the story scroll depth are they actually paying attention to the details. It does come down to the channel again things like cold outreach how did the cold outreach series with customer quotes or customers for isn't them compared to those that don't have a lot of comparisons and benchmarking but start the conversation  and avoid situations where you're just looking for