Ask a customer "how much did our product help?" and you get a rating, not a measurement. The question invites a compliment, and polite people give one. That is why most case study interviews end with quotes about "great team" and "easy to use" and no numbers a buyer can weigh.
The stakes are concrete. Adobe's team reports that 79% of buyers view case study content as part of their purchasing process, and 52% of B2B buyers rank case studies as an important part of their evaluation (Adobe). A buyer in evaluation mode is building an internal business case, which is where "they said it was amazing" loses to "invoice volume fell from 4,200 a month to 3,100, per their accounts payable export." Case studies work because buyers trust evidence more than claims (Articulate Marketing).
There is also a preparation failure that looks like an interviewing failure. Walking in blind, without knowing how the customer uses the product or what results they have seen, hands control to the interviewee, who defaults to adjectives. Experienced writers review usage and outcome data before the call and send questions in advance (Edify Content).



