Project management triangle: Difference between revisions

The Project Management Triangle

The Project Management Triangle is project management model represents the constraints of project management.

Overview

Like any human undertaking, projects need to be performed and delivered under certain constraints. Traditionally, these constraints have been listed as "scope," "time," and "cost". These are also referred to as the "Project Management Triangle," where each side represents a constraint. One side of the triangle cannot be changed without affecting the others. A further refinement of the constraints separates product "quality" or "performance" from scope, and turns quality into a fourth constraint.

The time constraint refers to the amount of time available to complete a project. The cost constraint refers to the budgeted amount available for the project. The scope constraint refers to what must be done to produce the project's end result. These three constraints are often competing constraints: increased scope typically means increased time and increased cost, a tight time constraint could mean increased costs and reduced scope, and a tight budget could mean increased time and reduced scope.

The discipline of Project Management is about providing the tools and techniques that enable the project team (not just the project manager) to organize their work to meet these constraints.

Another approach to Project Management is to consider the three constraints as finance, time and human resources. If you need to finish a job in a shorter time, you can throw more people at the problem, which in turn will raise the cost of the project, unless by doing this task quicker we will reduce costs elsewhere in the project by an equal amount.

Project management triangle topics

Time

For analytical purposes, the time required to produce a deliverable is estimated using several techniques. One method is to identify tasks needed to produce the deliverables documented in a work breakdown structure or WBS. The work effort for each task is estimated and those estimates are rolled up into the final deliverable estimate.

The tasks are also prioritized, dependencies between tasks are identified, and this information is documented in a project schedule. The dependencies between the tasks can affect the length of the overall project (dependency constrained), as can the availability of resources (resource constrained). Time is different from all other resources and cost categories.

According to PMBOK the Project Time Management processes include :

1. Activity Definition
2. Activity Sequencing
3. Activity Resource Estimating
4. Activity Duration Estimating
5. Schedule Development
6. Schedule Control

Activity Definition (detail)

1a. Activity Definition Inputs
Enterprise environmental factors, Organizational process assets, Project Scope statement, Work Breakdown Structure, WBS Dictionary, Project Management Plan
1b. Activity Definition Tools
Decomposition, Activity Templates, Rolling Wave Planning, Expert Judgment Collection, Planning Components
1c. Activity Definition Outputs
Activity list, Activity scope attributes, Milestones list, Change Requests

Activity Sequencing (detail)

2a. Activity Sequencing Inputs
Project Scope Statement, Activity List, Activity Attributes, Milestones List, Approved change requests
2b. Activity Sequencing Tools
Procedure Diagram Method (PDM), Arrow Diagramming Method (ADM), Schedule Network templates, Dependency degeneration, Applying leads and lags
2c. Activity Sequencing Outputs
Project Schedule Network diagrams, Activity List Updates, Activity Attributes Updates, Request Changes

Activity Resource Estimating (detail) :

3a. Activity Resource Estimating Inputs
Enterprise Environmental factoring, Organizational process assets, Activity list, Activity attributes, Resources Availability, Project Management Plan
3b. Activity Resource Estimating Tools
Expert Judgment Collections, Alternative Analysis, Publishing estimating data, Project management software implementation, Bottom up estimating
3c. Activity Resource Estimating Outputs
Activity resource requirements, Activity attributes, Resource breakdown structure, Resource calendars Request change updates.

Activity Duration Estimating (detail):

4a. Activity Duration Estimating Inputs
Enterprise environmental factors, organization process assets, Project scope statement, activity list, activity attributes, activity resource requirements, resource calendars, project management plan, risk register, activity cost estimates
4b. Activity Duration Estimating Tools
Expert judgment collection, analogous estimating, parametric estimating, three point estimating, reserve analysis
4c. Activity Duration Estimating Outputs
Activity duration estimates, activity attribute updates and estimates

Schedule Development (detail):

5a. Schedule Development Inputs
Organizational process assets, Project scope Statement, Activity list, Activity attributes, project Schedule Network diagrams, Activity resource requirements, Resource calendars, Activity duration estimates, project management plan, risk register
5b. Schedule Development Tools
Schedule Network Analysis, Critical path method, schedule compression, what if scenario analysis, resources leveling, critical chain method, project management software , applying calendars, adjusting leads and lags, schedule model
5c. Schedule Development Outputs
Project schedule, Schedule model data, schedule baseline, resource requirements update, activity attributes, project calendar updates, request changes, project management plan updates, schedule management plan updates

Schedule Control (detail):

6a. Schedule Control Inputs
Schedule management plan, schedule baseline, performance reports, approved change requests
6b. Schedule Control Tools
Progressive elaboration reporting, schedule change control system, performance measurement, project management software, variance, analysis, schedule comparison bar charts
6c. Schedule Control Outputs
Schedule model data updates, schedule baseline. performance measurement, requested changes, recommended corrective actions, organizational process assets, activity list updates, activity attribute updates, project management plan updates

Due to the complex nature of the Process Group called 'Time' the unique project management credential PMI-SP (PMI Scheduling Professional) was created.

Cost

To develop an approximation of a project cost depends on several variables including: resources, work packages such as labor rates and mitigating or controlling influencing factors that create cost variances tools used in cost are, risk management, cost contingency),cost escalation, and indirect costs . But beyond this basic accounting approach to fixed and variable costs, the economic cost that must be considered includes worker skill and productivity which is calculated using various project cost estimate tools. This is important when companies hire temporary or contract employees or outsource work.
Cost Process Areas

• Cost Estimating is an approximation of the cost of all resources needed to complete activities.
  
• Cost budgeting aggregating the estimated costs of resources, work packages and activities to establish a cost baseline.
  
• Cost Control - factors that create cost fluctuation and variance can be influenced and controlled using various cost management tools.
  

Project Management Cost Estimating Tools

• Analogous Estimating
  

Using the cost of similar project to determine the cost of the current project

• Determining Resource Cost rates
  The cost of goods and labor by unit gathered through estimates or estimation.
  
• Bottom Up estimating
  Using the lowest level of work package detail and summarizing the cost associated with it. Then rolling it up to a higher level aimed and calculating the entire cost of the project.
  
• Parametric Estimating
  Measuring the statistical relationship between historical data and other variable or flow.
  
• Vendor Bid Analysis
  taking the average of several bids given by vendors for the project.
• Reserve Analysis
  Aggregate the cost of each activity on the network path then add a contingency or reserve to the end result of the analysis by a factor determined by the project manager.
  
• Cost of Quality Analysis
  Estimating the cost at the highest quality for each activity.
  

Frequently project manager use project management cost software to calculate the cost variances on a project.

Scope

Requirements specified to achieve the end result. The overall definition of what the project is supposed to accomplish, and a specific description of what the end result should be or accomplish. A major component of scope is the quality of the final product. The amount of time put into individual tasks determines the overall quality of the project. Some tasks may require a given amount of time to complete adequately, but given more time could be completed exceptionally. Over the course of a large project, quality can have a significant impact on time and cost (or vice versa).

Together, these three constraints have given rise to the phrase "On Time, On Spec, On Budget." In this case, the term "scope" is substituted with "spec(ification)."