6 5 Estimate Activity Duration The process of

6. 5 Estimate Activity Duration The process of approximating the number of work periods needed to complete individual activities with the assigned or estimated resources • Previous experience in the type of project and activities being estimated greatly helps with the accuracy of duration estimates • Duration is a function of work effort and resources • Most project management software can perform this function Monitor • Occurs during the Planning Phase Initiation Planning Execution Close Control Adapted from PMBOK 5 th Edition

6. 5 Estimate Activity Duration Inputs to Estimate Activity Duration ü Schedule Management Plan ü Activity list and attributes ü Activity Resource requirements and estimates ü Resource Calendars ü Project Scope Statement ü Risk Register ü Resource Breakdown Structure ü Enterprise Environmental Factors: e. g. : Productivity metrics and estimating data ü Organisational Process Assets: e. g. : historical information Adapted from PMBOK 5 th Edition

6. 5 Estimate Activity Duration Tools and techniques to Estimate Activity Duration Analogous Estimating Three-Point Estimating Parametric Estimating Group Decision-Making Expert Judgement Reserve Analysis Adapted from PMBOK 5 th Edition

6. 5 Estimate Activity Duration Analogous Estimating ü Develops duration estimates based on previous projects or activities ü Can use duration, budget, size, weight, complexity as the basis of measurement ü Relies heavily on expert judgement and previous experience ü Less costly and less time consuming than other methods ü Least accurate ü Most common form of duration estimating Parametric Estimating 1 day per sqm ü Duration is quantified by multiplying the quantity of work by Monitor the labour hours required ü Relies on published estimating data ü Common in Construction Initiation Planning Execution Close Control Adapted from PMBOK 5 th Edition

6. 5 Estimate Activity Duration Three-Point Estimates - PERT ü Calculates the Expected activity duration based on the weighted average of the Most Likely, Optimistic and Pessimistic estimates ü Often more accurate than other methods and quantified range of uncertainty Reserve Analysis ü Inclusion of contingency 10% 20 % ü Can be calculated for each activity ü Can be calculated for entire project Monitor Initiation ü Often a percentage based on risk or complexity Planning Execution Close Control Adapted from PMBOK 5 th Edition

6. 5 Estimate Activity Duration The major output of this process ü Activity Duration Estimates ü Draft or High Level Project Duration Estimate Often include some form of range of possible results Most common form of range is plus or minus – e. g: ü 2 weeks +/- 2 days – the activity could take between 8 and 12 days ü 3 weeks +/- 30% - the activity could take between 2 weeks Monitor and 4 weeks Initiation Planning Execution Close Control Adapted from PMBOK 5 th Edition

6. 5 Estimate Activity Duration - Example ID Phase/Task Description Dependencies Duration Resources 1. Design Phase 2. Design Shed N/A 10 days Architect 3. Obtain Councils Approval 2 (Design Shed) FS 2 weeks Project Manager, Architect 4. Council Approval Obtained 3 (Obtain Councils App. . ) FS 0 days Project Manager 5. End design phase 4 (Council Approval Ob. . ) FS 0 days 6. Execution Phase 7. Sign contract 5 (End design phase) FS ½ day Project Manager, Client 8. Check existing boundaries 5 (End design phase) FS 1 day Surveyor 9. Check underground cable locations 5 (End design phase) FS 1 day Surveyor 10. Establish site services and amenities 5 (End design phase) FS 2 days Site Manager, Project Manager, Site Office 11. Excavate site 7 (Sign contract) FS 8 (Check existing boun. . ) FS 9 (Check underground. . ) FS 10 (Establish site servic. . ) FS 5 days Construction 1, Construction 2, Construction 3 4 th Edition Adapted from PMBOK