In evaluating software vendors in an area as specialised as public sector billing, the role of the vendor’s product manager is paramount.  He must be a person with extensive industry knowledge.  Why so?  Consider how software is developed.

Between 40% and 60% of software failures and defects are the result of poor software management and requirements definition. In plain English, this means that about half of the problems encountered could have been avoided by making it clear, from the very beginning, what the customer expected from the respective project. This is to say that the programming was fine and the developers did their job well - only they did a different job from what they were supposed to.

The definition of a successful program is that it is 100% compliant with its initial requirements. But it those requirements contain mistakes, are unclear or poorly defined, then there is very little one can do to correct the problem later in the process. So, a bit of advance planning simply doubles the success changes of any software project.

The person in charge with writing the requirements should be the product manager.  His job is to keep abreast of industry developments, and liaise with the team in charge with software engineering, all the stakeholders, the clients and the end-users. Writing good requirements takes time and practice.  It also needs extensive experience.  The best product manager is someone who is perhaps a former project manager, with a variety of projects under his belt, and knoweldge of how at least two different public sector billing applications tackle the same functional areas.