5th Edition PMBOK® Guide—Chapter 6: Process 6.5 Estimate Activity Durations


1. Introduction

Once the amount of resources that can be assigned to a project are known as a result of process 6.4 Estimate Activity Resources, then you can estimate the activity durations in the current process 6.5 Estimate Activity Durations.

2.  Inputs, Tools & Techniques, Outputs

The inputs come from previous processes in Time Management, such as 6.2 Define Activities and 6.4 Estimate Activity Resources, as well as from Scope and Risk Management. Risk Management is particularly important when it comes to the three-point estimating which take best-case and worst-case scenarios into account.

6.5 ESTIMATE ACTIVITY DURATIONS
INPUTS
1. Schedule Management Plan Identifies the scheduling method and tools to be used, as well as the level of accuracy used in creating activity duration estimates.
2. Activity List Identifies activities that will need duration estimates. Provides data to be used in estimating the resources required for each activity. This is an output of process 6.2 Define Activities.
3. Activity Attributes Provides data to be used in estimating the resources required for each activity. This is an output of process 6.2 Define Activities.
4. Activity Resource Requirements The estimated activity resource requirements will affect the duration of the activity. This is an output of process 6.4 Estimate Activity Resources.
5. Resource Calendars The availability of the resources will affect the duration of the activity. This is an output of process 6.4 Estimate Activity Resources.
6. Project Scope Statement Assumptions and constraints are considered when estimating activity durations. This is an output of process 5.6 Define Scope.
7. Risk Register Identified risks and their characteristics affect the schedule module. This is an output of Risk Management.
8. Resource Breakdown Structure Hierarchical representation of resources by category and type, typical categories being: labor, material, equipment, supplies. Output of process 6.4 Estimate Activity Resources.
9. EEFs
  • Duration estimating databases
  • Productivity metrics
  • Published commercial information
10. OPAs
  • Project files (duration information from previous projects)
  • Project calendars
  • Scheduling methodology
TOOLS & TECHNIQUES
1. Expert judgment Expert judgment can be used by using historical information to give duration estimates from similar projects. It can also used to reconcile different estimating methods.
2. Analogous estimating Uses a measure from a previous similar project to estimate the duration or cost of the current project in a top-down approach.
3. Parametric estimating Uses an algorithm to estimate the duration or cost of the current project based on historical data from previous similar projects.
4. Three-point estimating A single-point activity duration estimate can be improved by using the most likely, the optimistic (best-case), and pessimistic (worst-case) estimate for each activity. These three estimates can be combined by using the triangular or beta distribution formulas.
5. Group Decision-Making Techniques Team-based approaches can be useful for improving duration estimates.
6. Reserve analysis Duration estimates can use “contingency reserves” for risks in the risk register that the “known-unknowns” of the project.
OUTPUTS
1. Activity Duration Estimates The duration estimates may include a range of possible results.
2. Project Document Updates
  • Activity attributes
  • Assumptions made during the activity duration estimate

The tools and techniques are varied in terms of complexity and accuracy, and a comparison of these techniques will be taken up in the next blog post.

The outputs of the activity duration estimates are used directly in the next and final planning process for Time Management, 6.6 Develop Schedule.

Advertisements

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

%d bloggers like this: