What are three methods of duration estimation for project activities and what are the advantages and disadvantages of each method?

The assignment is to answer the question provided above in essay form. This is to be in narrative form and based on weekly reading.  This source should be a published article in a scholarly journal (Journal of Project Management) or a professional journal (such as PMI’s Project Management Journal). This source should provide substance and not just be mentioned briefly to fulfill this criteria. The journal article should not replace or provide information already in the textbook. It should be used to provide greater detail through examples, research, case studies, etc.