agile user stories: objection #1

User stories are a tool to ensure that requirements are communicated effectively between the business owner and the developers, and also to ensure that, as Mike put it ‘resource allocation becomes a shared problem [between the business owner and the developers]’. User stories are effectively a mechanism by which to ensure that developers have all the necessary information before they start building. Well, what is wrong with this? Absolutely nothing, I believe developers should be given all the right tools, information, and privileges so they can build working solutions. However, the problem lies in the fact that user stories are at best the output of brainstorming sessions and not the result of user research. I am struggling to understand how a group of developers and business owners can identify and list user needs in the form of stories without previously having done qualitative research. The agile answer is that project owners understand and own the users, which leads me to objection 2