Benefit of Using MRD
Question: "Quite frankly, so called product management is really all about having some good old fashioned common sense. For example, why do we need an MRD if with Agile we can just build the product as we go and suffice with a Product Backlog?"
Answer: Indeed a lot in product management represents common sense thinking. However, common sense alone is insufficient to generate results and promote efficiency. Required is a professional product management methodology that is comprised of extremely well-ordered and well-disciplined processes, accurate role descriptions and detailed task templates/checklists.
Agile is a product development method and it is not a technique for doing market research or planning products. The Market Requirements Document (MRD) is based on prior and continuous market research and therefore it encapsulates established market knowledge and represents a true understanding of customers and their needs.
Developing a product without an MRD will result in "Research-oriented Development", a situation where product development begins while there are incomplete, ambiguous or missing market requirements. This forces further learning of the market and cause occasional readjustments to the product's feature set while the product is being developed as more market knowledge is gained.
Although possible to reach the same product feature set with or without an MRD, it is the general opinion that with an MRD the effort required and the time duration needed to deliver a product are less than those without an MRD. This builds the notion that money can be saved when using an MRD as opposed to not using an MRD.
Please see the Benefit of Using MRD graphic.