2.1 Activity lists
The activity list is essentially an itemized documentation of all of the schedule activities that are part of a particular project. These lists are typically very detailed and comprehensive, providing as many details as possible to make it as easy and quick as possible for a user to attain general, broad sheet information. Some specific categories of information that should be included within the activity list can include the title or brief description of the activity, the detailed description of the activity, the unique activity identifier, a list of project team members who may be assigned to that particular activity. The detailed description of each activity is essential in providing all project team members with a big picture perspective of what is taking place, what work needs to be performed, and what their role will be within that activity. The activity list should be compiled as early in the process as possible to assure that all team members have a chance to review it.
2.2 Activity Attributes
Activity attributes typically refers to the specific components that make up an activity. These can include descriptive factors of the activity at the onset, or can also refer specific characteristics that may become relevant at a later phase of an activity. Activity attributes can be sorted, organized, and summarized according to some specific categories. Some types of activity attributes can include those related to time needed to complete specific components, costs related to completion of an activity or of some specific components, activity codes, responsible persons or persons involved in the activity, specific locations in which the activity may be taking place, or other miscellaneous categories into which these attributes can be conveniently and appropriately organized. Activity attributes can also include discussion of specific constraints that may make completion more difficult.
2.3 Project Schedule Network Diagram
A network diagram is a graphic representation of a series of activities and events depicting the various aspects of a project and the order in which these activities and events must occur. It reflects all activities and events from the beginning to the ending of the project. The few rules of networking may be classified as those basic to all arrow networking systems. Further information will be discussed hereunder.
2.4 Activity Resource Requirements
This includes any resources needed for a certain activity (labour, plant & materials required...etc)
2.5 Resource Calendars
This is the process of keeping track of schedules and time. One of the best ways to accomplish this feature is through the careful use of calendars to keep track of the project related events, occurrences, and dates that will take place during the project’s life cycle.
2.6 Activity Duration Estimates
Activity duration estimating will be used to calculate the number of work periods required to complete a certain activity.
2.7 Project Scope Statement
Identifies and describes all work necessary to reach the final results. The statement establishes the tone for the rest of the planning efforts and therefore should be adequately detailed.
2.8 Enterprise Environmental Factors
It is an input output mechanism that is meant to measure the particular environmental factors influence the ultimate success of a particular phase of a project or of the project as a whole.
2.9 Organizational Process Asset
List of any asset of the organizations involved in the project that can influence the success of the project one way or another.
3) Tools and Techniques
3.1 Schedule Network Analysis
Schedule network analysis, as defined by the Project Management Body of Knowledge (PMBOK), is a technique used by project managers to analyze schedule information and generate realistic and optimal project schedules. This analysis should be performed upon completion of the draft schedule and network diagram and after each schedule update. Schedule network analysis involves:
- Identifying the schedule impact of task dependencies
- Identifying critical path tasks and understanding the impact of the critical path on the schedule. Software tools such as Microsoft Project automatically display critical path tasks once project information such as tasks, dependencies, and durations are identified in the tools.
- Analyzing the effects of schedule constraints and externally imposed dates
- Understanding which tasks can experience delays without delaying the overall schedule
- Conducting “what if” analysis of various activity durations (for example, what if the testing activities take twice as long as is currently planned?)
- Assessing resource allocation and leveling to prevent resource over-allocation
- Assessing fast tracking or crashing options to ensure optimal schedule performance
3.2 Critical Path Method (CPM)
Critical Path Method (CPM) is a schedule network analysis technique that determines the shortest time to complete the project and it is the longest duration path through a network of tasks. The critical path method calculates the longest path of planned activities to the end of the project (the critical path) and the earliest and latest date that each activity can start and finish without extending the project. Any activity delay on the critical path impacts the planned project completion date. A network diagram visually conveys the critical path. This visibility into the critical path allows project managers to prioritize activities and take appropriate corrective actions to meet schedule deadlines. An understanding of the critical path also allows project managers visibility as to which schedule activities are flexible – that is, those activities that are not on the critical path. The essential technique for using CPM is to construct a model of the project that includes the following:
- A list of all activities required to complete the project (WBS)
- The duration that each activity will take to completion
- The dependencies between the activities.
Advantages of critical path method according to Lewis James in his book “Project Planning, Scheduling & Control”
1. Planning - Critical path methods first require the establishment of project objectives and specifications, and then provide a realistic and disciplined basis for determining how to attain these objectives, considering pertinent time and resource constraints. It reduces the risk of overlooking tasks necessary to complete a project, and also it provides a realistic way of carrying out more long-range and detailed planning of projects, including their coordination at all levels of management.
2. Communication - Critical path methods provide a clear, concise, and unambiguous way of documenting and communicating project plans, schedules, and time and cost performance.
3. Psychological - Critical path methods, if properly developed and applied, can encourage a team feeling. It is also very useful in establishing interim schedule objectives that are most meaningful to operating personnel, and in the delineation of responsibilities to achieve these scheduled objectives.
4. Control - Critical path methods facilitate the application of the principle of management by exception by identifying the most critical elements in the plan, focusing management attention on the 10 to 20 per cent of the project activities that are most constraining on the schedule. It continually defines new schedules, and illustrates the effects of technical and procedural changes on the overall schedule.
5. Training - Critical path methods are useful in training new project managers, and in the indoctrination of other personnel that may be connected with a project from time to time.
Disadvantages of critical path method according to Rupen Sharma who is “Certified Project Management Professional (PMP)”
- For large and complex projects, there’ll be thousands of activities and dependency relationships.
- For large projects with thousands of activities, it may be difficult to print the project network diagram.
3.3 Project Evaluation and Review Technique (PERT)
A Program Evaluation and Review Technique (PERT) chart is a method to visually represent a project. PERT charts are effective tools in showing activities and their relationships with other activities. PERT charts have two major components, arrows and nodes. Activities, called nodes, are connected by arrows with their previous and following activities. Once the activities are plotted and connected, a project manager can then determine the critical path. The critical path of a project can be defined as the sequence of activities that are essential to the completion of the project, and the duration of the project is affected by changing the duration of any of the activities on the critical path. CPM and PERT can be used together to have a better results.
3.4 Critical Chain Method
The basis for the critical chain method is the same as the basis for the critical path method but with one key difference; the critical chain method accounts for resource limitations. By adding resource limits to the analysis, the result is that critical path is generally longer. The resource-constrained critical path is known as the critical chain. If resources are allocated in the scheduling tool, the network diagram will display the critical chain. Using the critical chain method involves adding duration buffers to project schedules to protect the targeted finish date from slippage. Duration buffers are added to the schedule as non-work schedule activities, one at the end of the critical chain and others at the end of each sequence of tasks that feeds into the critical chain. As a result, “buffer” time is integrated throughout the project schedule to account for duration uncertainty. Later in the project, project teams monitor project progress by reviewing the consumption rate of the buffers.
3.5 Resource Leveling
Resource leveling is the process of changing schedule resource allocation to resolve over-allocations or conflicts. Resource leveling is applied to a schedule that has already been analyzed by the critical path method. This technique is used to adjust a project schedule if shared resources are only available at certain times, or in limited quantities, or if a Project Manager wants to maintain resource usage at a constant level. Resource leveling is often used to correct resource over-allocations and will often change the critical path. The network diagram should be recreated after resource leveling to assess the updated critical path.
3.6 What-if Scenario Analysis
This analysis examines the schedule impact of various scenarios, such as the delayed delivery of a major deliverable. What-if scenario analysis may include simulation that calculates multiple project durations with different sets of activity assumptions. Multiple network diagrams may be generated to visually convey the impact of varying scenarios. Project managers can use the results of this analysis to determine schedule feasibility under adverse conditions and prepare relevant contingency plans.
3.7 Applying leads and lags
Here, the project manager determines the needs that may require a lead or a lag to accurately define the logical relationship.
3.8 Schedule Compression
As a result of network diagram analysis, project teams may identify a need to compress the schedule. Schedule compression shortens the project schedule in order to meet schedule deadlines without reducing the project scope. Schedule compression techniques include crashing and fast tracking. If utilized, project teams should recreate and reassess the network diagram to ensure that no new schedule issues have emerged.
Crashing – Crashing involves either adding resources or increasing work hours to shorten task duration. Shorter task durations typically result in higher task costs, so project teams must determine, prior to crashing, whether the total costs savings is enough to justify the higher costs. It almost always requires cost increases because it usually necessitates new tasks. It is a controversial technique because adding project resources can increase project complexity or risk and may ultimately have a negative impact on the schedule. It does not involve reducing project scope or eliminating project tasks.
Fast Tracking – Fast tracking is a schedule compression technique in which project phases or activities usually conducted sequentially are performed in parallel to reduce duration. Care must be taken to ensure that parallel work does not create additional work or increase risk. Fast tracking frequently results in increased complexities in task needs, so additional project controls must be implemented to ensure ongoing and accurate insight into schedule performance.
4) Output
4.1 Project Schedule
Project Schedule is the outcome that provides a graphical representation of predicted tasks, milestones, dependencies, resource requirements, task duration, and deadlines. The project master schedule interrelate all tasks on a common time scale. The project schedule should be detailed enough to show each WBS task to be performed, the name of the person responsible to complete this task, the start date of each task, and the expected duration for each task. The project schedule is presented using one or more of the following formats:
4.1.1 Bar Charts
The project bar chart is a graphic illustration of the project or of a part of the project in which the dates and durations of the work packages can be seen. The activities are shown in bars proportional to the duration. These charts are easy to read and usually used in management presentations. Milestones chart and Gantt chart are examples of the Bar Charts. The bars represent activities, show activity start and end dates, as well as expected durations.
The steps followed in preparing a bar chart are as follows:
1. Analyze the project and specify the basic approach to be used.
2. Break the project down into a reasonable number of activities to be scheduled.
3. Estimate the time required to perform each activity.
4. Place the activities in sequence of t i e , taking into account the requirements that certain activities must be performed sequentially while others can be performed simultaneously.
5. If a completion date is specified, the diagram is adjusted until this constraint is satisfied.
The advantage of bar chart according to Lewis James in his book “Project Planning, Scheduling & Control” is that the plan, schedule and progress of the project can all be portrayed graphically together. Figure 1 show the five-activity plan and 15-week schedule, and current status (end of third week) indicates, for example, that activity B is slightly behind schedule. In spite of this important advantage, bar charts have not been too successful on one-time through projects with a high engineering content, or projects of large scope. The reasons for this include the following:
1. Planning and scheduling are considered simultaneously.
2. The simplicity of the bar-chart precludes showing sufficient detail to enable timely detection of schedule slippages on activities with relatively long duration times.
3. The bar-chart does not show explicitly the dependency relationships among the activities. Hence, it is very difficult to impute the effects on project completion of progress delays in individual activities.
4. The bar-chart is essentially a manual-graphical procedure. It is awkward to set up and maintain for large projects, and it has a tendency to quickly become outdated and lose its usefulness.
Figure 1
4.1.2 Milestone Chart
Milestones mark significant events in the life of a project, usually critical activities which must be achieved on time to avoid delay in the project. Milestones should be truly significant and be reasonable in terms of deadlines as shown in Figure 2. For example:
- installation of equipment;
- completion of phases;
- file conversion;
- Cutover to the new system.
Figure 2
4.1.3 Gantt Charts
A Gantt chart is a horizontal bar or line chart which will commonly include the following features:
- Activities identified on the left hand side;
- Time scale is drawn on the top or bottom of the chart;
- Horizontal line against each activity indicating estimated duration;
- At a review point the lines are shaded to represent the actual time spent;
- A vertical cursor placed at the review point.
Figure 3
Advantages of Gantt chart:
- They provide an easy graphical representation of when activities (might) take place.
Disadvantages of Gantt chart:
- Do not clearly indicate details regarding the progress of activities
- Do not give a clear indication of interrelation ship between the separate activities
4.1.4 Project Schedule Network Diagrams
Network diagrams are schematic displays of project schedule activities and the interdependencies between these activities. When developed properly, this graphical view of a project’s activities conveys critical schedule characteristics required to effectively analyze and adjust schedules – thus resulting in accurate and feasible schedules. Examples of network diagrams are the CPM and PERT.
Figure 4
4.2 Schedule Baseline
The schedule baseline represents the project team’s schedule commitment and it establishes target dates and time span for the accomplishment of activities. It also documents the project’s schedule assumptions. The schedule baseline provides a time perspective to the project team and sets benchmarks against which schedule performance is measured and forecasts projected.
4.3 Schedule Data
This includes the milestones, activities, attributes, and documentation of assumptions and constraints.
4.4 Project Documents Updates
Any documents might be updated. (Resource requirements, Attributes, Calendars, Risk register…etc).
5) Summary
Scheduling aims to predict the future, and it has to consider many uncertainties and assumptions. In project management, the schedule is a critical part of efforts. It identifies and organizes project tasks into a sequence of events that create the project management plan. A variety of inputs and tools are used in the scheduling process, all of which are designed to help the project manager understand his resources, his constraints, and his risks. The end result is a plan that links events in the best way to complete the project efficiently. The project schedule is the output of schedule development and there is different types of project schedules which in the format of diagrams or graphical charts. (Network Diagram, CPM, Critical chain method, Gantt charts…..etc).
7) References
- A Guide to the Project Management Body of Knowledge (PMBoK Guide) – Fourth Edition 2009’
- Practice Standard for Scheduling – by PMI ( Project Management Institute)
- Project Planning, Scheduling & Control, Lewis, James P., 1995
- Project Management, A Systems Approach to Planning, Scheduling & Controlling - Kerzner.
