8.3 Estimating the Resources

The goal of activity resource estimating is to assign resources to each activity in the activity list. In order to estimate resources, we can use the similar techniques that we utilized to estimate schedule (see Chapter 7) and cost (see Chapter 9). In this book, we will describe four tools and techniques for estimating activity resources.

1. Expert judgment: The project team consults domain and implementation subject matter experts who have technical knowledge and experience in the areas the project activities are related to. When we are developing a mobile application, we can consult software engineers, developers and testers, and systems analysts who were involved in activities to develop other mobile applications. They can provide us with information regarding resource requirements.
2. Alternative analysis: We can consider several different options for how we can assign resources. This includes varying the number of resources as well as the kind of resources we use. Many times, there’s more than one way to accomplish an activity and alternative analysis helps decide among the possibilities.
3. Analogous estimating: Information and lessons learned from previous projects, standards provided by the regulatory agencies, government organizations, and occupational associations, and the data that rely on articles, books, journals, and periodicals can be utilized to help us figure out what kind of and how many resources we need in our project activities.
4. Bottom-up estimating: We decompose our project activities by utilizing WBS. We break down complex activities into pieces. Therefore, we can work out the resource assignments for each piece. It is a process of estimating individual activity resource needs and then adding these up together to come up with a total estimate. Bottom-up estimating is an accurate means of estimating, given that the estimates at the lower levels are accurate. However, it takes a considerable amount of time to perform bottom-up estimating because every activity must be assessed and estimated accurately to be included in the bottom-up calculation. The smaller and more detailed the activity, the greater the accuracy and cost of this technique. An example is provided in the sections “8.4 Resource Allocation” and “8.5 Solving Resource Conflicts”.

Project management software programs such as Microsoft Project often have features designed to help project managers estimate resource needs and constraints and find the best combination of assignments for the project.