Maintaining estimation accuracy
It is easy to be misled when working with a small sample of data. This can be a serious issue when quoting a fixed fee for a big project if the quote is based on facts and figures that turn out to be inaccurate or irrelevant. Some factors that should be considered when calculating prices for quotes are:
Experience of working on an individual project may not be a true reflection of how easy or difficult it is to work with a client.
Different types of project have different levels of difficulty to implement.
A client may have better skills in some areas than others.
Client staff may move jobs and be replaced by new people throughout the project, resulting in whole new values generated for the client rating.
The client's personality, commitment, competence and contribution skills may change over time—leading to an improvement or deterioration in efficiency of the working relationship and the decreased accuracy of the client rating data you have previously collected...