First, what is the difference? Typically, case studies are more in depth, detailed descriptions of a customer situation, the problem and the process by which the problem was addressed. Success stories focus on, well – the success – or outcome and are briefer. Testimonials can be any type of accolade exclaiming your fantastic service or product. What should you use, if any, for your website or sales letter?
My recommendation is (like usual) – it depends. First we should note that prospects and customers are thinking about themselves – their concerns and burning issues. They need to see themselves in a situation – but if they get too much detail they can easily dismiss the example (“that’s not my industry” or “but I have this product problem”).
For websites where many suspects (versus real prospects) may visit, they are looking for indicators to ensure they can trust your company, your claims and your experience. In this case logos of past companies, links to press reviews or rotating testimonials quickly convey that message.
For sales proposals to real prospects carefully chosen examples of similar problems you have solved or industries you have served help take you to the next level of discussion. But again this is a subtle supporting point rather than a key strategy to close a sale.
Don’t agree? Have an example of how a case study brought you business? Let me know.