An often overlooked piece of the requirements gathering and documenting portion of a project is assuming that everyone understands the assumptions. Almost every project document includes a list of assumptions. Problems arise when the assumptions are not clear or when some are left off of the document. You may feel that something is so obvious that it does not need to be included. The mistake there is that there may be people new to the organization reviewing the document that do not have the common knowledge that those who have been there for a while do. It is always better to over documents and list obvious assumptions that to leave some off and have it become a problem later. A missing assumption may turn into a piece of functionality or item of work that a stakeholder thought was going to be included. This can turn into issues between the stakeholders and project team which may result in final signoff being withheld or a costly change being implemented later in the project. It is also important to verify each assumption with each stakeholder to make sure they all have the same understanding. A review of the list of assumptions should be part of each project document signoff meeting. Many assumptions deal with what other project teams are working on or what will be out of scope and it is crucial that everyone has the same understanding. If an assumption does include another project team make sure that that team is aware and agrees that they are responsible for their portion of the work. Taking extra care with any assumptions you include will make sure "what they say about assumptions…" will not happen to you.