Defining the Change RequestThe answer to this question depends on how one defines submitting, filing, or "raising" a Change Request (CR). If it means submitting the request to the Change Control Board (CCB), expecting its approval, then one definitely should perform the analysis first.
However, I define filing a CR as placing it under control of the CCB. That does not mean that the entire board oversees the CR before it has been analyzed. It means that the CR is entered into a Change Request Log so it can be tracked and analyzed with adequate oversight.
Preventing Duplicated AnalysesPerforming the analysis before filing the CR implies that, if the request is not practical, the Change Request may never be filed. That can cause problems.
Suppose the customer suggests a change to the Chief Engineer, and the CE does an analysis of the change. Then the customer suggests the change to the Project Manager, and he does a separate analysis. Later, one of the engineers thinks of the same change and does yet another analysis. Do you see the waste?
To avoid such waste, an organization should have a coordinator act as gatekeeper for the Change Control Board. Each Change Request (CR) should be filed with the facilitator before an analysis is performed. The coordinator can cross-reference the change against previous CRs to identify similar or duplicate analyses that have already been performed. This prevents duplicated effort. The coordinator can also suggest other resources, such as studies or subject matter experts. Or, the coordinator might create efficiency by combining the analysis with another activity.
Tracking ProgressNow, imagine that the customer asks the PM to make a change, and the PM performs an analysis, but it falls off the PM's desk into the trash can and is forgotten. Later, the customer sues the company because it did not make the requested change.
Instead, imagine that the PM filed the CR with the CCB coordinator FIRST, before analyzing the impact. The coordinator would create an entry in the Change Request Log and assign a due date for the analysis. When the due date comes, the coordinator asks the PM, "where's your analysis?"