6.4 – Estimate Activity Resources

The process of estimating the type and quantities of material, human resources,equipment, or supplies required to perform each activity.

  1. Inputs – Schedule management plan, Activity list, Activity attributes, resources calendars, risk register, activity cost estimates, enterprise environmental factors, organizational process assets.
  2. Tools – Expert judgement, alternative analysis, published estimating data, bottom up estimating, project management software
  3. Outputs
    1. Activity resource requirements -with this output we determine what types or resources we need, their availability, and quantity.
    2. Resource breakdown structure – Like WBS, RBS is an hierarchical representation of resources by category and type. (Check image for example)
    3. Project documents updates.

6.5 – Estimate Activities Duration

In this process we estimate how much time it will take to complete each activity. The main output of this process is schedule baseline.

  1. InputsSchedule management plan, Activity list, Activity attributes, project schedule network diagrams, activity resource requirements, activity duration estimates, project scope statement, risk register, project staff assignment, resource breakdown structure, enterprise environmental factors, organizational process assets.
  2. Tools – Expert judgment, analogous estimating, parametric estimating, three point estimation, group decision-making techniques, reserve analysis.
  3. Outputs -Activity duration estimates, Project documents updates.
  • The first three techniques are based on experience and historical information.
  • When applying DELPHI technique we seek to get estimates from several (5-6) experts. Each expert submits his estimate independently from each other’s (the expert don’t even know who the other experts are). Then the project team collects the estimates and compares them. Then the similar estimates and best practices are being used, and topics with high variance is sent to round B. If round B comes back again with high variance, the project team will refer to other methods.
  • Analogous estimating – This is basically using past experience from similar projects, based on the company or industry information. This is also referred to as top to bottom estimating.
  • Parametric estimating – If we cannot evaluate an activity duration, we will decompose the activity into a smaller activities, then we estimate the smaller activities separately. This is also known as bottom to  top estimating.

Three Points Estimation

  • Three Points Estimation This technique is very useful in case there isn’t enough historical information. To apply this technique
  • We take three estimates – Optimistic, Most Likely, and Pessimistic and we place them in the following formula
    • To use Triangular distribution – Time(Estimated) = (Time(O) + Time(M) + Time(P))/3
    • To use Beta distribution – Time(Estimated) = (Time(O) + 4Time(M) + Time(P))/6

Reserve analysis

  • We should always have reserves in our project (both schedule and money) to compensate for uncertainties and risks.
  • We have three ways to analyze reserves.
    • As a fixed amount on the project total. In this case, it is ok that the reserve balance decreases as the project progresses, but we must manage it and make sure it is not being used to quickly.
    • As a fix percentage on each activity, or a fixed number on each activity
    • Using analytical analysis of the project activities and scope.
  • It is important to know that reserve in the context of schedule is called buffer, and in the context of money it is called reserve.

6.6 – Develop Schedule

  1. Inputs – Project Management Plan, Activity List, Activity Attributes, Project Schedule Network Diagrams, Activity Resource Requirements, Resource Calendars, Activity Duration Estimates, Project Scope Statement, Risk Register, Project Staff Assignments, Resource Breakdown Structure, enterprise environmental factors, organizational process assets.
  2. Tools -Schedule Network Analysis, Critical path method, Critical chain method, Resource optimization techniques, Modeling techniques, leads and lags, Schedule compression, Scheduling tool.
  3. Outputs -Schedule baseline, project schedule, schedule data, project calendars, project management plan updates, project documents updates.
  • Critical path – Used to determine the minimal amount of time required to complete the project. Does not take into consideration buffers, limited resourced, uncertainties etc.
  • Critical chain – Takes into account limited resources, schedule buffers, risks etc.

Schedule Network Analysis

  • Allows the project team to identify point in time where planning flexibility is available by “…identifying early and late start dates, as well as early and late finish dates, for the uncompleted portions of project schedule activities“.
  • In the critical chain method:
    • Forward Pass – A critical path method technique for calculating the early start and early finish dates by working forward through the schedule model from the project start date or a given point in time.
    • Backward Pass –  A critical path method technique for calculating the late start and late finish dates by working backward through the schedule model from the project end date.
    • If the free float equals the total float it mean that the successor activity is on the critical path.
    • Early Finish Date (EF) – The earliest possible point in time when the uncompleted portions of a schedule activity can finish based on the schedule network logic, the data date, and any schedule constraints.
    • Early Start Date (ES) – The earliest possible point in time when the uncompleted portions of a schedule activity can start based on the schedule network logic, the data date, and any schedule constraints.
    • Late Finish Date (LF) – The latest possible point in time when the uncompleted portions of a schedule activity can finish based on the schedule network logic, the project completion date, and any schedule constraints.
    • Late Finish Date (LF) – The latest possible point in time when the uncompleted portions of a schedule activity can finish based on the schedule network logic, the project completion date, and any schedule constraints.
    • Total Float – The amount of time that a schedule activity can be delayed or extended from its early start date without delaying the project finish date or violating a schedule constraint.
    • Free Float –  The amount of time that a schedule activity can be delayed without delaying the early start date of any successor or violating a schedule constraint.
    • Float is calculated using forward and backward pass

Schedule Compression

  • Resource leveling – A technique in which start and finish dates are adjusted based on resource constraints with the goal of balancing demand for resources with the available supply.
    This technique has an impact on the critical path. It usually makes it longer.
  • Resource smoothing – A technique which adjusts the activities of a schedule model such that the requirement for resources on the project do not exceed certain predefined resource limits.
    This technique has no impact on the critical path. Activities can be extended only within their free or total float.

 

6.7 – Control Schedule

  1. This is the process of monitoring the status of project activities to update project progress and manage changes to the schedule baseline to achieve the plan.
  2. Inputs – Project Management plan, Project schedule, Work performance data, project calendars, schedule data, organizational process assets.
  3. ToolsPerformance reviews, project management software, resource optimization techniques, modeling techniques, leads and lags, schedule compression, scheduling tools.
  4. Outputs – work performance information, schedule forecasts, project management plan updates, project documents updates, organizational process assets updates.

PMI Spirit

  1. Be realistic – Before execution phase start, a realistic project schedule should be determined
  2. Ongoing schedule measurement is required throughout the project.
  3. As PM – Focus on monitoring and controlling critical and near critical path activities.
  4. The critical is the longest duration path through the network diagram, and determines the shortest time needed to complete the project.
  5. Important part of schedule control is to decide if variation from the planned scheduled is such that requires a corrective action.

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