Estimating Schedule Durations Using MS Project PERT Analysis

Estimating Schedule Durations Using MS Project PERT Analysis Tool Presented by Harry Smith MPUG St. Louis Chapter Member February 9, 2011 1

Agenda �What is PERT? �Estimating �Project Industry Best Practices Management Scenario �Challenges �Opportunities � PERT for improvement Analysis tool demo �Questions 2

PERT � rogram valuation and eview echnique �Critical path is calculated based on: ◦ Estimated durations of activities ◦ Links between the activities (predecessor/successor relationships) �Collect a range of estimates using a weighted average for the duration estimates 3

Some Industry Best Practices �Multiple estimates (i. e. , bottom-up & top down) �Project team members are the best source of task estimates �Leverage tools if possible �Historical data can be very helpful 4

Estimate Attributes �Exact-estimate �Realistic is an oxymoron estimates must be: ◦ Specific ◦ Repeatable ◦ Defendable 5

Estimating Inputs �Subject matter experts (SME) have been identified for estimating tasks �The WBS has been defined and converted to schedule tasks/activities �The project task dependencies have been identified �Identify which tasks/activities will be estimated using the PERT analysis tool 6

Project Management Scenario �Deliver software components for new web-based applications and enhancements to legacy systems �Manage the project cost, schedule, and effort within ± 10% of baseline estimates 7

Challenges �Schedule customer. delivery dates were fixed by the �Costs were constrained by budget estimates set with very few requirements. �Delivery scope was somewhat flexible. �Historically, estimated project completion dates were not very accurate. �In fact, individual task estimates were not very accurate. 8

Opportunity for Improvement �Post-project analysis discovered that schedule variances were primarily due to weak task estimates. �Focus on improving estimating procedures and techniques without drastically impacting how long it takes to prepare estimates. 9

MS Project and PERT � Getting toolbar started – activate the PERT Analysis 10

MS Project and PERT � Click on PERT entry sheet toolbar icon on PERT Entry Form icon and enter values 11

MS Project and PERT � Click on the PERT weighting icon to set weighting values 12

MS Project and PERT �On the PERT toolbar click on the calculation icon to calculate the task average weighted duration �Next go to the duration field and round up or down to whole numbers as appropriate �Tip: When you hit the calculation icon this will not undo like other actions in MS Project 13

MS Project and PERT �Adding a text field for comments allows you to document any assumptions that were used to come up with values. ◦ Remember specific, repeatable, and defendable 14

Questions 15

PDU for Members & Guests: �PDU activity code is: mpugstlouis 020911. �PDUs can be claimed under category 3 on the PMI website. Contact info: Harry Smith email: harry. l. smith@frb. stls. org 16