Chap 6.4 Estimate Activity Duration

PMBOK 6 - All rights reserved; By: Anand Bobade (nmbobade@gmail.com)
Trainer: Anand BobadePMBOK 6th Edition, 2019, All rights reserved.
Estimate Activity
Duration
PMPChapter 6 –
Project Schedule Management
SIXTH EDITION

6.4 Estimate Activity Duration
Overview
Estimate Activity Duration Definition
Important terms
Estimate Activity Duration : ITTO
Estimation techniques – Analogues, Parametric, 3P
Duration estimate & basis of estimation
Review

Schedule Management processes
Plan Schedule
management
Define Activities Sequence Activities
Estimate Activity
Duration
Develop Schedule Control Schedule
P P P
MCP P

Estimate Activity Duration-> Introduction
SME Technical Lead
Solution Architect Quality expert
Estimation is joint activity, respective experts has to
estimate their work. PM is responsible to aggregation.

Resources Advances in technology
Staff Motivation Law of diminishing returns
Estimate Activity Duration-> Key factors than influences estimation:
Key factors than influences estimation:

The number of resources
•Increasing the number of resources to twice does not always
reduce the time by half.
•It may increase extra duration due to risk.
Advances in technology
•Plays an important role in estimating duration.
•Ex: Road construction work can be expedited by procuring fully
automated machines.
•This may impact duration, cost and resource needs
Staff Motivation
•Aware of the Student Syndrome or procrastination.
•When resources start working at last possible moment before the
deadline, Parkinson’s Law come in effect.
•Parkinson’s Law - Work expands to fill time available for its
completion

Law of diminishing
returns
Refer to a point at which, benefits gained is less than the amount of efforts and/or
money invested.
When one factor, e.g., resource is increased, & all other factors remain fixed, you may get
increased output.
However, A point will eventually be reached at which additions of that factor start to
yield diminishing output.
1
2
3

Example: Painting a house
Estimate Activity Duration-> Important Terms
• 20 daysEfforts
• 10 days
• With 2 resources
Duration
• 15 days
• Includes (2 weekends & 1 day holiday by resources)
Elapsed Time
Day1 Day2 Day3 Day4 Day5 Day6 Day7 Day8 Day9 Day10 Day11 Day12 Day13 Day14 Day15
Work Started
1-Jan (Sunday)
Work completed
15-Jan (Sunday)
Weekend Weekend
Resource on
Holiday

Estimating number of work periods needed to complete each
activity with estimated resources.
It is a major input to Develop Schedule process.
Activity
Estimate Activity Duration -> Definition
Estimating
Work Periods per
activity
With estimated
resources

Estimate Activity Duration -> ITTO
Expert Judgments
Analogous Estimates
Parametric Estimates
Three point estimates
Bottom up estimates
Data analysis
Decision making
Meetings
Project Management
plan
Project Documents
Enterprise
environmental factors
Organizational process
assets
Duration Estimates
Basis of estimates
Project documents
updates
Inputs Tools & Techniques Outputs

Estimate Activity Duration -> Input
Project Management
plan
Project Documents
Enterprise
Organizational process
assets

Project
Management plan
Following PMP subsidiary plans & baselines can be used as input:
Estimate Activity Duration -> Input -> PMP
Schedule Management
plan
Scope baseline
Scope baseline -> Project Scope statement:
• Project scope statement provides description of the
• Project scope, Major deliverables, Assumptions & Constraints
• Expect senior expert to work on the technical design due to requirements complexity.
• Impact on estimation: Longer estimate; multiple resource may not be able to reduce
estimate proportionally.
Assumption
• Requirement has to be implemented before 1-Aug, due to government legislation.
• Impact on estimation: Multiple resource may be added to shorten the duration of
activity.
Constraint

Project Documents
Following Project Documents can be used as input:
Activity list
Activity
attributes
Assumption
log
Resource
breakdown st.
Resource
Requirements
Risk Register
Resource
Calendar
Milestone list
Lessons
Register Reg.
Project team
assignments
Estimate Activity Duration -> Input -> Project documents

Activity list:
• A list of all activities under each work package.
Activity ID WBS Id Name Description
501 W50 Compare Furniture brands
502 W50 Find showrooms
503 W50 Get Quotes
504 W50 Compare Quotes
Estimate Activity Duration -> Input -> Project documents ->Activity List

Activity attributes:
• Additional details of activities, which are useful for estimation.
Predecessor
activities
Successor
activities
Logical
relationships
Leads and lags
Resource
requirements
Imposed
dates
Constraints Assumptions
Person
responsible
Geographic
area or place
Calendar
Estimate Activity Duration->Input->Activity Attributes

Resource Requirements:
• The types and quantities of resources required for each activity in a work package.
• Aggregated to determine resource estimation for each work package.
Estimate Activity Dur.->Inputs-> Resource Requirement
Activity
ID
WBS
Id
Name Resource Type Quantity
601 W51 Unit Testing Developer 5
602 W51 System Testing Test Analyst 10
603 W51 Performance Testing Sr. Performance Test
Analyst
2
604 W51 Security testing Security expert 2
Resource Type Resource Quantity
Total Resources for
Work Package

Resource Calendars:
• Identifies working days & shifts when each resource is available.
• Details about how long resource will be available.
• Other details – Skill, Skill levels, location etc
Estimate Activity Duration->Input->Resource Calendar
•Resource may be material, human resources, equipment etcRemember:

Risk Register:
• Concerns with results of Risk analysis & response planning.
• List of Risks related to estimations & resources.
Estimate Activity Duration->Input->Risk Register

Resource Breakdown Structure:
• Hierarchical representation of resources by category or type.
• Used for searching Resources.
Construction Project
Labor
Managers
Manager1
Manager2
Workers
Worker1
Worker2
Worker3
Material
Building
Office setup
Equipment
Desktop
Laptop
Printer
Projector
Supplies
Printer
Cartridges
Papers
Stationary
Estimate Activity Duration->Inputs-> RBS

Enterprise
Duration
estimating
databases & other
reference data.
Productivity
metrics.
Published
commercial
information.
Location of team
members.
Estimate Activity Duration -> Input -> EEF

Organizational
process assets
Historical
duration
information.
Project
calendars.
Scheduling
methodology.
Lessons
learned.
Estimate Activity Duration -> Input -> OPA

Estimate Activity Duration ->Tools & Techniques
Expert Judgments
Analogous
Estimates
Parametric
Estimates
Three point
estimates
Bottom up
estimates
Data analysis Decision making Meetings

Expert
Judgement
All estimations should be done by Experts. Expert can be internal or external.
Complex project need many experts.
General schedule
development
Management and
control
Expertise in
estimating
Estimate Activity Duration -> T&T -> Expert Judgement

Analogues
estimation
Estimate duration of activity using historical data from a similar activity or a project.
Uses historical information, expert judgment.
Think “analogy” – something similar
Relatively quick and low cost
It is gross value estimation approach.
Parameters used:
Duration Budget Size Weight Complexity
Estimate Activity Duration -> T&T -> Analogues estimation

Parametric
estimation
Algorithm is used to calculate duration based on historical data & project parameters.
Uses statistical relationship between historical data & other parameters.
• Accuracy of historical data.
• Sophistication & scalability of model.
• Quantifiable parameters
Accuracy is
based on:
Estimate Activity Duration -> T&T -> Parametric estimation
Railroad Project Highway Project
E.g., Construction
estimation
software

Bottom up
estimates
Estimate the duration of each activity
Then aggregate the estimates for the different level of components as per WBS
Advantage • It is accurate
Disadvantage • It is time-consuming.
Estimate Activity Duration ->Tools & Techniques-> Bottom up estimate
Sum up the durations
of each activity for
each work package,
Sum up the subtotals
for each work
package,
Rolling up the levels of
the WBS until you get
estimate for entire
project.

Three point
estimation
Estimate duration by applying an average of optimistic, pessimistic & most likely
estimates.
This is also called as PERT techniques (Program Evaluation and Review Technique).
• = (O + M + P) / 3Triangular Distribution
• = (O + 4M + P) / 6
Beta Distribution
(Weighted average)
Estimate Activity Duration->T&T->Three point estimation
What's efforts required for activity1:
Most likely = 12 hours (Regular prog.)
Optimistic = 10 hours (coding guru)
Pessimistic = 16 hours (New prog.)
Estimation Discussion meeting
• = 10+12+16 / 3
• = 12.66 hours
Triangular
• = [10 + (4X12) +
16] / 6
• = 12.33 hours
Beta

Data analysis
Following Data analysis techniques will be used:
Reserve Analysis:
• To determine the amount of
contingency and management
reserve needed for the project
Alternative analysis:
• Used to compare various levels of
resource capability or skills;
• different tools(manual vs.
automated); and make, rent, or buy
decisions regarding the resources
Estimate Activity Duration -> T&T -> Data analysis

Data analysis
Reserve
Analysis
Contingency reserves are used in schedule to account schedule uncertainty.
PM has to use reserve to protect baseline & constantly reduce or eliminate it.
Quantitative analysis like Monte Carlo can be used to identify reserves.
Estimate Activity Duration -> T&T -> Data analysis
Reserve can be @
Activity level
Work package
level
Can be fixed
amount
Can be % of the
estimates

Decision
making
Voting
Estimate Activity Duration ->T&T -> Decision making
How it works?
Closed fist
indicates no
support
Five fingers open
indicates full
support
if less than 3 fingers are
opened, then the objection
is discussed until everyone
has 3 or more fingers open
Fist of five (or fist to five) voting in agile:
• technique used by agile software development teams to
poll team members & achieve consensus.

Meetings
In agile, sprint or iteration meetings is used to discuss the prioritized product backlog
Done on day 1, & attended by product owner, Scrum team & PM/Scum Master
Stories are broken into tasks, which are estimated & checked against team capacity
Estimate Activity Duration ->T&T -> Meetings
Results in Sprint backlog Assumptions Constraints Risks Dependencies
Decision &
actions

Estimate Activity Duration -> Output
Duration
Estimates
Basis of
estimates
Project
documents
updates

Duration
Estimates
Estimate Activity Duration->Output->Duration estimates
• It is important to properly communicate
estimates.
• Estimates should be given in range.
• State the confidence level in estimates.
Communicating
estimate:
Sr. No Activity Duration
1 Requirement Gathering 30 days
2 Development 90 days
3 System Testing 15 days
4 User acceptance Testing 20 days
5 Performance Testing 5 days
6 Handover 5 days
7 Project closure 5 days
These are estimated duration, which are likely number of time periods required to
complete the activities.

Basis of
estimates
known constraints, project risk which influence estimates
Documentation of how the duration estimates were developed
Indication of range of estimates (ex: +/-10%),
Confidence level of the final estimate
Estimate Activity Duration -> Output

Project
Documents
Following Project Documents may get updated.
Estimate Activity Duration -> Output -> Project document updates
Activity
attributes
Assumption log
Lessons
Learned Reg.

Estimate Activity Duration->Review
Overview
Estimate Activity Duration Definition
Important terms
Estimate Activity Duration : ITTO
Estimation techniques - Analogues, Parametric, 3P
Duration estimate & basis of estimation

Chap 6.4 Estimate Activity Duration

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