Estimate activity duration

Estimating Activity Duration-SAYALI

Estimating Activity Duration This process estimates the time period

required to complete individual activity.

Duration includes actual amount of time worked on an activity plus elapsed time.

Effort is the number of workdays or work hours required to complete a task.

Effort does not normally equal duration.

Estimating Activity Duration Contd… This Process is a major input into the

Develop Schedule Process.

People working on project should create duration estimates, and an expert should review them.

Estimate durations become accurate progressively as data becomes accurate.

Estimates decides approximate work periods required as per project and resource calendars.

Estimating Activity DurationInputs

• Schedule management plan• Activity list • Activity attribute • Activity resource

requirement • Resource calendar• Project scope statement• Risk register• Resource breakdown

structure• Enterprise environmental

structure• Organizational process assets

Tools & Techniques

•Expert judgement •Analogous estimating•Parametric estimating•Three point estimating

•Group decision making techniques

•Reserve analysis

Outputs

•Activity duration estimates

•Project documents updates

Inputs Schedule Management Plan- Defines method and accuracy level to estimate project update cycle.

Activity List- Lists down activities requiring duration estimates.

Activity Attributes- Provides primary data input to estimate duration for each item in activity list.

Activity Resource Requirement- Skill set of the resources assigned to activity determines duration.

Resource Calendars- Decides the scheduling of specific skilled and general resource to activity.

Inputs contd… Project Scope Statement – Describes assumptions and constraints when estimating duration. Eg- Existing conditions, Available information and skilled resources.

Risk Register – Describes risk, risk analysis and response planning. Documents are updated.

Resource Breakdown Structure – Provides hierarchical structure of resource by category and type.

Enterprise Environmental Factors – Factors that can influence estimate of activity duration. Eg- Reference data duration, location of team members, productivity matrix.

Organizational Process Assets – Factors like Project calendars, Scheduling methodology, Earlier mistakes can influence estimate of activity duration.

Tools and TechniquesExpert Judgment – Gives recommendation on maximum activity duration and determines combining methods of estimation and reconciling differences from similar experiences.Analogous Estimating – Technique to estimate duration or cost, uses historical data and parameters from similar projects as basis for setting parameter for future project. Cost and time effective but less accurate.Parametric Estimating – Uses algorithm to calculate cost and duration on historical data and parameters. Statistical relationship between historical data and variables calculate estimate for activity parameters.

Tools and Techniques Contd…Three Point Estimates- Program evaluation and review technique uses three estimates to estimate uncertainty and risk which are

-Most likely considers average resources to calculate timeframe. -Optimistic considers best resources to calculate timeframe. -Pessimistic considers worst resources to calculate timeframe.

Group decision making techniques- Involves group of expert people to gain additional information to improve estimate accuracy and also brings commitment to achieve results.

Reserve Analysis- Consider time reserve or buffers allocated to identified risk accounting for schedule uncertainty.

OutputsActivity Duration Estimates-

Involves quantitative assessments to calculate a likely number of time periods to complete an activity. Estimates do not include any lags. -2 weeks +/- 2 days, which indicates that the activity will take at least eight days and not more than twelve(assuming a five-day workweek); and

-15 % probability of exceeding three weeks, which indicates a high probability—85 %—that the activity will take three weeks or less.

Project Documents Updates- Project documents that may be updated include, but are not limited to:

-Activity attributes; and assumptions made in developing the activity duration estimate, such as skill levels and availability as well as a basis of estimates for durations.

ConclusionThis is an important process as it decides the timeframe required for each project activity.

If any duration estimate goes wrong or some complex situation or risk is not identified it can hamper the entire project.

Result will be increase cost, additional pressure on team, upset shareholders and can have serious effect on entire project.

Thank You

References

http://getpmpcertified.blogspot.ca/2011/05/chapter-37-estimating-activity-duration.html

A Guide to the Project Management Body of Knowledge, 5th edition.