Agile uses mostly user stories to capture requirements. In his blog post, Jean-Jacques Dubray explains that there is a problem with user stories because they tend to focus on the solution and not on the problem definition.
User stories are base on actions and actions are solution centric and should not be part of the problem definition. Jean-Jacques Dubray suggests that “we make a very simple and easy change to Agile and replace “user stories” by “problem statements”. Each problem must be “solutioned”, either by decomposing it into simpler problems or solutioning it directly.”
This post is completed by a very valuable comment from Mike Cohn who wrote that “User stories are not meant to be the high-level thinking about a product. They are an output of that thinking. That is, a product owner should convene a meeting with individuals who can help solve a problem.”
Read the complete post on http://www.ebpml.org/blog2/index.php/2013/04/26/reinventing-agile-from-value-to