1. Activity Definition Activity List Resource Plan Activity sequencing Activity Resource Estimating Activity Duration Estimating Duration Estimate Network Diagram Schedule Development Integrated Schedule

2. Activity Duration Estimating Activity durations are the “calendar” time required to perform the work Duration comprises: Time spent by the resources actually performing the work Queue, wait or other inactive times Other times required before the effort is complete (eg. Paint cure times, automated test run times)

3. Duration Estimating Techniques Expert judgment Analogous Parametric Probabilistic

4. Expert Judgment Usually performed “bottom up”, often in conjunction with cost estimates performed as part of the proposal process Performed by “experts”: Functional “leads”/managers Consultants/Suppliers Project Management Staff Advantages: Buy-in from performing staff and/or management Detailed treatment Disadvantages: Can be overly optimistic/pessimistic depending on estimator bias Tendency to “build in” slack time

5. Analogous Estimating Usually performed, “Top down” - a form of expert judgment that uses information from previous similar estimates to generate duration estimates Usually performed by experienced project manager, manager, marketing person Example: Property X is a 6 story building which took 6 weeks to erect; property Y is a similar type of building with same foundation footprint and utilities, but 3 stories tall – estimate it takes 3 weeks to erect Advantages: Quick, inexpensive estimate that can be performed before product team is assigned Can be applied to even relatively poorly defined activities Disadvantages: Only useful when projects are similar in fact, not just in appearance (eg. Property X built in Toronto, Property Y built in Greenland) Difficult to apply to lower level tasks

6. Parametric Estimating Used for repetitive tasks where metrics are maintained Number of engineering drawings Square feet of construction Lines of programming code Example: SW Coding=4 hours/line of code Advantages: Quick and easy to use Can draw on “Industry standard” handbooks which base estimates on broad data sets (eg. Construction estimating guides) Disadvantages Most project work does not fall into this category Only applicable where large data sets are available, yielding relevant averages

7. Example: SW Lines of Code Estimated Development Effort: (Basic COCOMO model, Person-Months = 2.4 * (KSLOC**1.05)) Estimated Schedule: (Basic COCOMO model, Months = 2.5 * (person-months**0.38))

8. Probabilistic Estimating The methods so far produce “Deterministic” estimates Useful if the duration is known with a fair amount of certainty (eg. Time to produce a test report) For most estimates, the duration is uncertain (eg. Time to run the test: what if it fails? No equipment? Equipment fails? Etc.) in this case, need some way to account for the “probability” of things going better or worse than planned Two methods of accounting for uncertainty: Weighted average estimate Three point estimate used in schedule risk simulation

9. Weighted Average Estimates Probability follows a distribution (eg. For most naturally occuring phenomena = the “normal distribution or “bell curve”) Activity durations do not typically follow a “normal” distribution left skewed – ie. The difference between the soonest completion and the most likely completion date is smaller than between the mostly likely date and the latest completion early studies by US DoD lead to adoption of a “triangular distribution” called the “PERT distribution” because it was used in the “Program Evaluation and Review Technique” concurrently developed A single point estimate for a PERT distributed task is Where to , tm , and tp are the optimistic, “most likely” and pessimistic estimates Example: a test usually takes 2 days to set up and run; if setup goes smoother than usual it takes 1 day; if the test equipment breaks down and needs maintenance, it takes 5 days for this, and the initial 2 days for set up and running = 7 days to tm tp to +4 tm + tp 6 Estimated duration 1 +4x2 + 7 6 to tm tp Estimated duration = = 2.4 days

10. Schedule Risk Modelling Statistical techniques used to “model” entire schedule based on multiple duration estimates for each task Eg. Monte Carlo analysis to , tm , and tp are input into a random number generator which produces an estimated time for each task Sample total schedule duration is calculated by applying sequence logic Process is iterated until a “steady” distribution of final durations is modelled

11. Adding Schedule Duration Entering into the Activity List Entering into the “Task Info” box

12. Schedule “Leads” and “Lags” Technique that introduces a time delay to a sequencing relationship to add realistic timing without unnecessary tasks Eg. Allow time for the customer to approve test results add a lag = 36FS+4d, the phone call will now happen 1d after the paperwork starts Must exercise caution not to replace actual work with a lag (eg. Time between work completion and shipment may include test, inspect, paperwork – these should be tasks)

13. Typical Activity Duration Estimating Procedure During proposal phase, the proposal manager and/or project manager produces a high level schedule based on an analagous estimate During the preliminary planning phase, detailed activity duration estimates are developed by team leads using expert knowledge and parametric estimating where possible Upon review of the preliminary schedule, critical and near-critical paths may be subjected to risk modelling to identify areas for mitigation planning, and possible schedule reserve allowances During project execution, team leads revise duration estimates using expert knowledge modified by analagous estimating drawn from project experience to date