PM tutor. Estimate Activity Durations Part 2. Presented by Dipo Tepede, PMP, SSBB, MBA. Empowering Excellence. Powered by POeT Solvers Limited

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1 PM tutor Empowering Excellence Estimate Activity Durations Part 2 Presented by Dipo Tepede, PMP, SSBB, MBA

2 This presentation is copyright 2009 by POeT Solvers Limited. All rights reserved. This presentation is protected by the Nigerian Copyright law and may not be reproduced, distributed, transmitted, displayed, published or broadcast without the prior written permission of POeT Solvers Limited. You may not alter or remove any trademark, copyright or other notices. PMP, CAPM, PMI, PMBOK Guide are registered marks of Project Management Institute, Inc.

3 At the end of this training, our goal is for you to: Be able to explain why we use analogous estimating Be able to define factors that influence the precision of parametric estimating Be able to describe three point estimates Be able to name the PERT formula Be able to explain why we give estimation ranges

4 Estimate Activity Durations T&T Expert Judgment Analogous Estimating Parametric Estimating Three-point Estimates Reserve Analysis

5 Expert Judgment Ask the experts Complex projects require cooperation of many disciplines Nobody can have all the experience Experts have years of experience They can fall back on their know-how, experience and their gut-feeling

6 Estimate Techniques Analogous Estimating Parametric Tracking Estimating Systems Three-Point Estimates

7 Analogous Estimating An estimating technique that uses the values of parameters, such as scope, cost, budget, and duration or measures of scale such as size, weight and complexity from a previous, similar activity as the basis for estimating the same parameter or measure for a future activity.

8 Why use Analogous Estimating? When little information is known about the project When two projects look similar Is fast and doesn t cost much Precision may be an issue

9 Parametric Estimating An estimating technique that uses a statistical relationship between historical data and other variables to calculate an estimate for activity parameters, such as, scope, cost, budget, and duration. An example for the cost parameter is multiplying the planned quantity of work to be performed by the historical cost per unit to obtain the estimated cost.

10 How? Use variables from Project Description Apply Mathematical Formula Develops an Estimate

11 Parametric Estimating Accuracy Accuracy of Parametric Estimating varies widely. Gets accurate when? Historical data are accurate Parameters are quantifiable in the model There is a scalable model that works on small and large projects

12 Three-Points Estimates An analytical technique that uses three cost or duration estimates to represent the optimistic, most likely and pessimistic scenarios. This technique is applied to improve the accuracy of the estimates of cost or duration when the underlying activity or cost component is uncertain

13 Three-Point Estimating Optimistic? Most Likely? Pessimistic? Take uncertainties into consideration Also referred to as PERT (Program Evaluation and Review Technique)

14 Formula PERT (Pessimistic + (4*Most Likely) + Optimistic) 6

15 To estimate a project, work out how long it would take one person to do it then multiply that by the number of people on the project

16 Reserve Analysis Analyze estimates: Who did the estimation? Who is going to perform the task? How complex is the task? Reserve is used during the project or eliminated

17 Estimate Activity Duration Output Activity Duration Estimates Project Document Updates Approval Levels

18 Always give a Range Never give an estimate that is just one number.

19 Where to Document? Where to document In Activity Attributes What to document Duration estimate for each schedule activities Assumptions made Contingencies

20 Remember What was said about doing all of the processes in Project Time Management as one big blob.

21 Sample Questions Favorite question target are the 3 estimation techniques. What are they? Analogous Estimating Parametric Estimating Three-Point Estimating Bottom-Up Estimating

22 Sample Questions Answers to questions in terms of durations and resources depends on the context of the question and the given parameters. What is the duration of a 20-hour activity resources that has 2 resources assigned that are 100% productive? Answer: 10 hours 50% productive 20 hours

23 Sample Questions What is the duration of a 20-hour activity that has 2 resources assigned that are 100% productive and are willing to work 2 hours of overtime? Answer: 10 hours

24 Review How long does this take? Specialists use their expert judgment and the 3 estimating techniques to give a duration for each activity. Add reserves Each estimate is a range, like it takes 3 weeks plus/minus 10% to finish the preliminary design.

25 Exam Tip Begin with a self assessment and estimate how long you will take to study for the exam.