14 OPERATIONAL PLANNING TECHNIQUES (USE OF PLANNING TOOLS LIKE GANTT CHART, PERT/CPM)

Mrs Renu Arora

I. Objectives

The objectives of this unit/module are, to:

Introduce the concept of operational planning
Discuss different operational planning techniques
Explain the importance of Gantt Charts in operational planning
Elucidate the techniques of network analysis with special focus on PERT and CPM

II. Learning Outcome

After going through this unit/module you would learn that operational planning is day-by-day and month-by-month planning for what an organisation is doing. You would learn the need for operational planning in libraries; various operational planning techniques; role of Gantt Charts in operational planning; network fundamentals; network diagram with PERT/CPM, and difference between Gantt Charts and PERT/CPM.

III. Structure

1. Introduction

1.1 Strategic planning vs. operational planning

2. Operational Planning

2.1 Project graphics

2.2 Techniques of Operational Planning

3. Gantt Chart

3.1 Use of Gantt Charts as a tool

3.2 Drawing a Gantt chart

3.3 Advantages and Disadvantages

4. Network Analysis

4.1 Use of Network Analysis as a Tool

4.2 Process of Network Analysis

4.3 Techniques of Network Analysis

5. PERT/CPM

5.1 Developing a Network

6. Difference between Gantt Charts and PERT/CPM

7. Summary

8. References

1. Introduction

Planning is determining what needs to be done, by whom, and by when in order to fulfil one’s assigned responsibility. Planning varies at each level of the organisation. At the functional level, planning must include agreement on purpose and coordination of work activities.

Operational planning is the day-by-day and month-by-month planning for what an organisation is doing. The strategic planning on the other hand determines the entire direction of an organisation, including what it is not doing but should be doing. The two forms of planning must be integrated, but must not be confused.

Plans are sets of goals and ways to attain them. Without a plan, managers and their subordinates may not be able to achieve their goals or even know when they have deviated from the right path. Strategic plans are those established to meet an organization’s extensive goals. On the other hand, operational plans are those that contain fine points for executing or implementing, those strategic plans in everyday activities.

1.1 Strategic planning vs. operational planning

Planning can best be described as the function of selecting the organisational objectives and establishing the policies, procedure and programmes necessary for achieving them. Also referred to as long-range planning, the term “strategic planning” expresses the analytic and comprehensive elements of planning in libraries and information organisations. The strategic plan aims to focus on a library’s vision and priorities in response to the changing environment. These plans also ensure that staffs of the library are working toward the same goals.

Operational planning on the other hand may be described as establishing a predetermined course of action with a forecasted environment and its requirements set the major milestones. If the library managers cannot commit because the milestones are perceived as unrealistic, the operational manager may have to develop alternatives, one of which may be to move the milestones. Top management must be involved in the selection of alternatives.

2. Operational Planning

An operational plan is necessary to ensure that the activities of the library and its services are focused on achieving the priorities and goals identified in the strategic plan. The plan should reflect the following:

– a focus on services to users

– implementation of the priorities and goals of the strategic plan

– formation of operational elements of the agreed strategies

– development of clearly identified goals with manageable and achievable time frames

– definition of achievable outputs for the level of inputs

– participation of library staff who carry out the activities

– allocation of responsibility to identified staff members for achieving outputs

– a schedule for monitoring, evaluating and revising the plan at regular intervals, if needed

Operational planning must be systematic, flexible enough to handle unique activities, disciplined through reviews and control and capable of accepting multi-functional inputs. Successful operational managers realise that operational planning is a repetitive process and must be performed throughout the span of the plan. One of the objectives of operational planning is to completely define all work required so that it is readily identifiable to all concerned.

Poor operational planning leads to:

– Plan initiation without defined requirements

– Wild enthusiasm

– Disillusionment

– Chaos

2.1 Project graphics

A project is a plan, proposal or a scheme with a set of interrelated tasks to be executed over a fixed period and within certain cost and other limitations. In other words,it a temporary endeavour undertaken to create a unique product or a service.

This definition highlights some essential features of a project, which are:

– it is temporary – it has a beginning and an end, and

– it is “unique” in some way.

With regard to the use of the term unique, it refers to non-repetitive or non-routine, for example, automating the very first library was a project, running an automated library now is a repetitive/routine process, not a project.

In India, we have some major projects in real-life, e.g., the Delhi Metro Rail, Mumbai’s Eastern Freeway, Chenab Bridge, New Swanky Double Decker Express Trains, Yamuna Expressway, etc.

Typically all projects have to be broken down into:

– separate activities (tasks/jobs) – where each activity has an associated duration or completion time (i.e., the time from the start of the activity to its finish), and

– precedence relationships – which govern the order in which we may perform the activities, e.g., in a project concerned with building a house the activity ‘erect all the four walls’ has to be finished before the activity ‘lay roof on’ can start.

And the problem is to bring all these activities together in a logical manner to complete the project.

We have already established that a formal programme plan with detailed schedules to manage the total programme is required while preparing the operational plans. Any plan, schedule, drawing or specification that be read by more than one person must be expressed in a language that is understood by all recipients.

The ideal situation is to construct charts and schedules in suitable notation that can be used by all for status reporting. It should consist of three vital control parameters:

– Time

– Cost

– Performance

All schedules and charts should consider these three parameters and their relationship to corporate resources. Information to ensure proper plan evaluation is usually obtained through four methods:

– First hand observation

– Oral and written reports

– Review and technical interchange meetings

– Graphical displays

First hand observations are an excellent tool for obtaining unfiltered information, but they may not be possible in large plans. Although oral and written reports are a way of life, they often contain either too much or not enough details, and significant information may be disguised. Review and technical interchange meetings provide face-to-face communication and can result in immediate agreement or problem definition or solutions, such as changing a schedule. The problem here is that only those present can reach a solution. Good graphic displays make the information easy to identify and are the prime means for tackling cost, schedule and performance. Proper graphical displays can result in:

– Cutting planning costs and reducing time scale

– Coordinating and expediting planning

– Eliminate idle time

– Obtaining better scheduling and control of delegation of activities

– Developing better troubleshooting procedures

– Cutting time for routine decisions, but allowing more time for decision-making

2.2 Techniques of Operational Planning

An operational plan is the chief key for managing any organisation. It provides the library manager with detailed information on the work that must be done to ensure that planned goals and objectives are achieved. The tools of operational planning provide practical information on how to implement the objectives, strategies and programs suggested in the corporate plan of the information organisation.

Operational planning in information organisations is a challenging task with many complex responsibilities. There are many tools available to assist for accomplishing the tasks and executing the responsibilities. Some require a computer with supporting software, while others can be used manually. Information managers should choose anoperational management technique/tool that best suits their management style.

Some of the major operational planning techniques are:

a. Risk Management

b. Budgetary Control

c. Work Breakdown Structure

d. Gantt Charts

e. Critical Path Analysis or Network Analysis

f. Resource Histograms

g. Milestones, Checkpoints and Gates

Risk Management In operational planning there is always a risk or chance that adverse conditions occur that may cause a project to fail or fail to meet its planned objectives in terms of time, cost and quality. Risk management addresses the identified risk issues in advance and helps to contain them. For example, in a proposed library automation system for a library, the key risks can be identified in advance. These could be insufficient budget or misunderstanding actual requirements of end users or lack of experience of library staff or introduction of possible new technologies in near future, etc. Appropriate risk management strategies help to take immediate action in case of possible unwanted occurrences.

Budgetary Control Budgets help in authorising expenditure, communicating objectives and plans, controlling operations, coordinating activities, evaluating performance, planning and rewarding personnel based on performance. Budgetary control, therefore, compares the budgeted results as a yardstick in comparison to actual results in order to quantify deviations from the operational plan. The whole process, at regular intervals, throughout the implementation phase of the plan can be used to take control action and bring actual results in line with the plans.

Work Breakdown Structure (WBS) The purpose of the work breakdown structure is to help plan effectively for a project by breaking key tasks and activities into more manageable and small units of work. WBS thus produces a detailed list of tasks to be performed, helps to deliver better costing, scheduling and resource planning for a project.

Gantt Charts A Gantt Chart is a horizontal bar chart used for project scheduling. Each task of activity is depicted as a block overtime, actual performance is recorded in real time and compared to planned deadlines necessary for achieving completion. This will be discussed in detail in the next section.

Critical Path Analysis or Network Analysis When projects are complex and lengthy, Gantt Charts are not suitable time management tools. In large projects, there often exists a high interdependency between various tasks, for example, some activities cannot started, until others have been completed first, therefore, many activities are interrelated. Gantt charts are thus less desirable as they do not display or indicate interdependencies. Network or Critical Path analysis can display more logically the sequence and timing of each activity. They communicate interdependency and a more effective time management tool for large or complex projects.

Resource Histograms A Resource Histogram is a bar or column chart that shows the number of resources assigned to a project over a period of time. Resource histograms usually presented as bar charts, can be an effective tool for planning of resources and coordinating staff of a project.

Milestones, Checkpoints and Gates Milestones are significant events in the course of a project that are used to give visibility of progress in terms of achievement of predefined milestone goals. Failure to meet a milestone indicates that a project is not proceeding to plan and usually triggers corrective action by management. Milestones thus are points of completion or achievement on a plan.

Checkpoints are calendar points at which the project reports progress, for example, weekly checkpoint meetings.

Gates are significant events or major objectives that have been accomplished at various stages of a project. They assess key completion or quality of work achieved. Gates are formal points in the project where resourcing for continued work is agreed.

Of the above mentioned, no single tool addresses all project management requirements. Gantt Charts and Network Analysis are two of the most commonly used operational planning tools in project management. In the subsequent sections, Gantt Charts and two techniques of network analysis – Program Evaluation Review Technique (PERT)and Critical Path Method (CPM) are described in detail as these are found to be most suitable in library and information organisations. Both of these techniques can be adopted manually or with commercially available project management software.

3. Gantt Chart

A Gantt chart is a horizontal bar chart developed as a production control tool in 1917 by Henry L. Gantt, an American engineer and a social scientist. Frequently used in project management, a Gantt chart provides a graphical illustration of a schedule that helps to plan, coordinate, and track specific tasks in a project.

3.1 Use of Gantt Charts as a tool

Gantt Charts (Gant Charts) are useful tools for analysing and planning more complex projects. They:

– Can be used to plan time scale for a project,

– Help to plan, coordinate and track specific tasks that need to be completed for a project,

– Can be used to estimate required resources,

– Give a basis for graphic scheduling when these tasks will be carried out,

– Allow to plan the allocation of resources needed to complete the project,

– Are good for small projects when the number of tasks or activities are small and not complex, and

– Help to work out the critical path for a project which has to be completed by a particular date.

The charts may be in the form of any of the following:

a. Scheduling or progress charts, which show the sequence of job progress.

b. Load charts which show the work assigned to a work group or allocated to machines.

c. Record charts which track the actual time spent and delays, if any.

Gantt charts need to be updated at regular intervals. For example, charts have to be updated – when a work is delayed at the start or when work continues beyond its time schedule or if the progress of work is not as per the actual plan. If unforeseen eventualities occur, corrective actions may have to be taken, and this will also need corresponding changes in Gantt charts.

A Gantt chart isa matrix which lists on the vertical axis all the tasks to be performed. Each row contains a single task identification which usually consists of a number and name. The horizontal axis is headed by columns indicating estimated task duration, skill level needed to perform the task and the name of the person assigned to the task, followed by one column for each period in the project’s duration. Each period may be expressed in hours, days, weeks, months and other time units. In some cases it may be necessary to label the period columns as period 1, period 2 and so on.

The graphical portion of the Gantt chart consists of a horizontal bar for each task connecting the period start and period ending columns. A set of markers is usually used to indicate the estimated and the actual start and end. Each bar on a separate line and the name of each person assigned to the task is on a separate line. In many cases, when this type of project plan is used, a blank row is left between tasks.

When the project is under way, this row is used to indicate progress, indicated by a second bar which starts in the period column when the task is actually started and continues until the task is actually completed. Comparison between the estimated start and end and the actual start and end should indicate project status on a task-by-task basis. Variants of this method include a lower chart which shows personnel allocations on a person-by-person basis. For this section, the vertical axis contains the number of people assigned to the project, and the columns indicating task duration are left blank, as is the column indicating persons assigned.

The graphics consist of the same bar notation as in the upper chart indicates that the person is working on a task. The value of this lower chart is evident when it shows the slack time for the project personnel, i.e., times when they are not actually working on any project.

Gantt Charts help to monitor whether the project is on schedule or not when a project is under way. If it is not, it allows to pin-point the remedial actions necessary to put it back on schedule. The Gantt chart shows the relationship between different activities over a time span.

3.2 Drawing a Gantt chart

As mentioned above, a Gantt chart is a bar chart that shows the tasks of a project, when each must take place and how long each will take. As the project progresses, bars are shaded to show which tasks have been completed? People assigned to each task also can be represented. To draw up a Gantt chart (Gantt diagram), follow these steps:

i. Identify tasks:

– Identify the tasks needed to complete the project.

– Identify key milestones in the project by brainstorming a list, or by drawing a flowchart, storyboard or arrow diagram for the project.

– Identify the time required for each task.

– Identify the sequence, i.e., which tasks must be finished before a following task can begin or which can happen simultaneously or which tasks must be completed before each milestone.

ii. Draw a horizontal time axis along the top or bottom of a page. Mark it off in an appropriate scale for the length of the tasks (days or weeks).

iii. Down the left side of the page, write each task and milestone of the project in order. For events that happen at a point in time (such as a presentation), draw a diamond under the time the event must happen. For activities that occur over a period of time (such as developing a plan or holding a series of interviews), draw a bar that spans the appropriate times on the timeline: Align the left end of the bar with the time the activity begins, and align the right end with the time the activity concludes. Draw just the outlines of the bars and diamonds; do not fill them.

iv. Check that every task of the project is on the chart.

v. As events and activities take place, fill in the diamonds and bars to show completion. For tasks in progress, estimate how far along task has reached and fill in that much of the bar.

vi. Place a vertical marker to show where project is on the timeline. If the chart is posted on the wall, for example, an easy way to show the current time is with a heavy dark string hung vertically across the chart.

Besides drawing manually, there are many other ways to create a Gantt Chart. For example, Microsoft Project, a task planning program, makes it easy to track and chart project timelines with a built-in Gantt chart view. Another option is to use Excel. Excel does not contain a built-in Gantt chart format, however, we can create a Gantt chart in Excel by customizing the stacked bar chart type. Using these not only eases the drawing of Gantt Charts, they also make modification of plans easier and provide facilities for monitoring progress against plans, as well as generating resource
histograms.

Gantt charts are thus useful tools for planning and scheduling projects. They allow us to assess how long a project should take, determine the resources needed, and layout the order in which tasks need to be carried out. They are useful in managing the dependencies between tasks. When a project is under way, Gantt charts are useful for monitoring its progress. One can immediately see what should have been achieved at a point in time, and can, therefore, take remedial action to bring the project back on course. This can be essential for the successful and profitable implementation of the project.

An example of Gantt chart with various details and a diagram can be seen
at http://en.wikipedia.org/wiki/Gantt_chart.

3.3 Advantages and Disadvantages

This is a simple and very inexpensive method and can be developed even by supervisory staff withvery little training. The charts visually depict complex ideas in totality.
These charts clearly show the decided time and work schedules for every job, thereby increasing visibility.
Monitoring and control are easier and can be done within a minimum time frame and at the lowest cost.
These charts can be changed and updated quickly at a very low cost.
Gantt charts are presentation tools that show the key milestones of a project.
The bars on the charts indicate the period in which a particular task or set of task will be completed. This helps to understand what is happening in the project all the time.

Disadvantages

In spite of the above-mentioned advantages, there are certain disadvantages.

1. A major disadvantage of Gantt charts relates to task dependencies. When project managers are illustrating tasks in a project, sometimes they want to show how the tasks depend on one another. Unfortunately, the Gantt chart’s format does not allow for this. They also do not show job interrelationships and interdependence.

2. Cost implications cannot be shown.

3. With these charts, it is not possible to depict other alternatives for project completion.

4. The shape and form of Gantt charts can differ according to the nature of the requirement. Also the size of the bars on the chart does not indicate the amount of work.

5. The charts need to be updated constantly.

6. Gantt charts are not flexible as they cannot accommodate changes once the project has commenced. A change to the schedule requires redrawing of the chart.

7. As the Gantt chart does not highlight work breakdown structure (WBS) elements, it has the highest risk of failure or delay.

4. Network Analysis

Network analysis is the general name given to certain specific techniques which can be used for the planning, management and control of projects. It is defined as

‘Breaking down’ a complex project’s data into its component parts, i.e., activities, events, durations, etc. and plotting them to show their interdependencies and interrelationships.

According to McGraw-Hill Dictionary of Scientific & Technical Terms, network analysis is an analytic technique used during project planning to determine the sequence of activities and their interrelationship within the network of activities that will be required by the project. It is also known as network planning.

In libraries and information organisations, network analysis helps to plan, carry out and complete various small and large projects by analysing the project activities. Each project isdivided into individual tasks and activities, which are arranged in logical sequence. The sequence in which the tasks are to performed including those to be carried out simultaneously has also to be decided before commencement of the project. Eventually a network diagram has to be constructed depicting relationship between various tasks, activities and their sequence. Finally costs, time and other resources are allocated to variousactivities.

Network analysis is an effective and powerful method of assessing:

– What tasks must be carried out

– Where parallel activity can be performed

– The shortest time in which one can complete a project

– Resources needed to execute a project

– The sequence of activities, scheduling and timings involved

– Task priorities

– The most efficient way of shortening time on urgent projects

4.1 Use of Network Analysis as a Tool

Network analysis or critical path analysis is a useful tool for lengthy and complex projects. Their usefulness is as below:

Good planning and visual communication tool for effective time management.
Clearly displays interdependent relationships that exist between the different activities or tasks to be completed.
Arranges activities and tasks into proper sequence of events enabling a project to be completed in the most efficient time possible
Helps to calculate estimated time or elapsed time to complete a project.
Highlight the activities that are considered critical, i.e., those activities which have to be completed with their planned time to complete the projects.
Identify the critical and non-critical activities.

4.2 Process of Network Analysis

The process of network analysis is:

a. Break down project into a logical sequence of activities to be completed.

b. Estimate the time duration of each activity.

c. Arrange activities in the most efficient sequence of events and estimate the elapsed time of the project.

Network analysis has some advantages as below:

– Identifies interrelationships between different tasks or activities.

– Resources can be planned and allocated for appropriate use.

– Good communication and planning tool for time management.

Besides the advantages mentioned above, there are also some disadvantages of network analysis:

– In case of larger projects, the complexity of the network diagram increases as number of activities increases.

– There is a definite relationship between time and money but personnel cost is usually a fixed and not a variable cost.

– While estimating the duration of activities, key uncertainties often exist which lead to poor prediction of elapsed time.

4.3 Techniques of Network Analysis

Two techniques for network analysis were developed independently in the late 1950’s – these were:

– PERT (Program Evaluation and Review Technique); and

– CPM (Critical Path Method)

PERT (Program Evaluation and Review Technique) was developed by the US Navy for the planning and control of the Polaris Missile Program and the emphasis was on completing the program in the shortest possible time. In addition, PERT has the ability to cope with uncertain activity completion times. For example, for a particular activity the most likely completion time is 4 weeks but it could be anywhere between 3 weeks and 8 weeks.

PERT charts depict tasks, duration, and dependency information. Each chart starts with an initiation node from which the first task, or tasks, originate. If multiple tasks begin at the same time, they all start from the node or branch, or fork out from the starting point. Each task is represented by a line which states its name or other identifier, its duration, the number of people assigned to it, and in some cases the initials of the personnel assigned. The other end of the task line is terminated by another node which identifies the start of another task, or the beginning of any slack time, that is, waiting time between tasks.

Each task is connected to its successor tasks in this manner forming a network of nodes and connecting lines. The chart is complete when all final tasks come together at the completion node. When slack time exists between the end of one task and the start of another, the usual method is to draw a broken or dotted line between the end of the first task and the start of the next dependent task.

A PERT chart may have multiple parallel or interconnecting networks of tasks. If the scheduled project has milestones, checkpoints, or review points (all of which are highly recommended in any project schedule), the PERT chart will note that all tasks up to that point terminate at the review node.

Importance of PERT Because it is primarily a project-management tool, a PERT chart is most useful for planning and tracking entire projects or for scheduling and tracking the implementation phase of a planning or improvement effort. It is also important due to following:

– Reduction in cost

– Saving of time

– Determination of activities

– Elimination of risk in complex activities

– Flexibility

– Evaluation of alternatives

– Useful in effective control

– Useful in decision making

– Useful is research work

CPM CPM (Critical Path Method) was developed by Du Pont and the emphasis was on the trade-off between the cost of the project and its overall completion time. When time is less of an uncertainty and the project has relatively routine task, CPM is more likely to be useful. It also distinguishes activities critical and non-critical for maintaining the schedule. For example, for certain activities it may be possible to decrease their completion times by spending more money. How does this affect the overall completion time of the project?

Critical Path Method (CPM) charts are similar to PERT charts and are sometimes known as PERT/CPM. In a CPM chart, the critical path is indicated. A critical path consists of a set of dependent tasks (each dependent on the preceding one) which together take the longest time to complete. Although it is not normally done, a CPM chart can define multiple, equally critical paths. Tasks which fall on the critical path should be noted in some way, so that they may be given special attention. One way to do this is to draw critical path tasks with a double line instead of a single line.

The Critical Path Method (CPM) is one of several related techniques for doing project planning. CPM is for projects that are made up of a number of individual “activities.” If some of the activities require other activities to finish before they can start, then the project becomes a complex web of activities.

Therefore, CPM can help to figure out:

– how long a complex project will take to complete, and

– which activities are “critical,” meaning that they have to be done on time or else the whole project will take longer.

If weput in information about the cost of each activity, and how much it costs to speed up each activity, CPM can help to figure out:

– whether we should try to speed up the project, and, if so,

– what is the least costly way to speed up the project.

Activities An activity is a specific task. It gets something done. An activity can have these properties:

– names of any other activities that have to be completed before this one can start

– a projected normal time duration

In the next section, we will discuss PERT/CPM as operational planning technique.

5. PERT/CPM

While planning library and information centre projects, the PERT and CPM techniques have been used jointly to plan and control the progress of the projects from start to finish. This technique has been most suitable especially for highly complex and long-term projects. PERT and CPM are used together as scheduling techniques to plan, schedule, budget and control the many activities associated with projects in libraries and information organisations. These projects are usually very large, complex, and consist of many interrelated activities to be performed either concurrently or sequentially. Utilizing PERT/CPM involves breaking the total project down into many different individual activities with identifiable time requirements. Each activity must be accomplished as part of the total work to be done.

The project’s desired completion date is the focal point for scheduling. The time to begin work on the project is determined by working backward from the desired completion date. Project managers must coordinate each of the activities so the project can be completed at the desired date and with minimal costs. The PERT/CPM schedule allows for converting the project plans into an operating timetable; thus providing direction for managing the day-to-day activities of projects.

Although application of both PERT and CPM follow the same steps and use network diagrams to schedule and control projects, the primary difference between these two techniques is that PERT is probabilistic where CPM is deterministic. The terms PERT and CPM are usually used together or interchangeably in this context.

5.1 Developing a Network

A network is a graphic plan of all the activities and events that must be completed to reach the end objectives of a particular project. It should show the planned sequence of their accomplishments, their dependencies and inter-relationships. Every PERT/CPM network has two basic components, namely, Event and Activity. Before developing a network, it is essential to know some terms related to network planning methods.

PERT/CPM Terminology

Event An event is a point in time, i.e., a milestone in the total work to be accomplished. It marks the beginning and end of an activity. Events do not consume resources or time. Events are numbered with those at the tail of the activity having lower numbers than the events at the head of each activity arrow (left to right). Events are represented by circles (nodes) and the event number is written within the circle.

Event is a point that marks the start or completion of one or more tasks. It consumes no time, and uses no resources. It marks the completion of one or more tasks, and is not “reached” until all of the activities leading to that event have been completed. Event is:

– A predecessor event: an event (or events) that immediately precedes some other event without any other events intervening. It may be the consequence of more than one activity.

– A successor event: an event (or events) that immediately follows some other event without any other events intervening. It may be the consequence of more than one activity.

Activity Every project consists of a number of jobs or tasks called as activities. Activities are to be accomplished as part of the total work to be done. Activities consume resources and/or time. They lie between two events and can be identified with starting and ending points. The network activities are represented by arrows and can be referred to by their endpoints and/or a letter assigned to the arrow.

Activities can be:

Critical activities:If an activity consumes more than its estimated time, it is called a critical activity. An activity becomes critical when its earliest start time plus the time taken by it is equal to the latest finishing time. A critical activity is indicated by marking a thick arrow to distinguish it from non-critical activities.

Non-critical activities: The activities that have provision, so that even if they consume more than estimated time, do not result in project delay.

Dummy activities: When two activities commence at the same time, their head events are joined by a dotted arrow is known as a dummy activity. Dummy activities do not consume time and may be critical or non-critical.

Precedence Relationships Some activities cannot begin until others have been completed. Precedence relationships must be defined in order to determine the sequence of activities in the network.

Path A sequence of activities that leads from the starting node to the finishing node.

Critical Path Critical path, formed by critical activities is the longest path through a network and consumes maximum time. The critical path is the minimum time for expected completion of the entire project. Each of the activities on the critical path has zero slack. The sequence of activities in a network can have more than one critical path.

Duration is the estimated or actual time required to complete a task or an activity.

Optimistic time (O): the minimum possible time required to accomplish a task, assuming everything proceeds better than is normally expected
Pessimistic time (P): the maximum possible time required to accomplish a task, assuming everything goes wrong (but excluding major catastrophes).
Most likely time (M): the best estimate of the time required to accomplish a task, assuming everything proceeds as normal.
Expected time (TE): the best estimate of the time required to accomplish a task, assuming everything proceeds as normal (the implication being that the expected time is the average time the task would require if the task were repeated on a number of occasions over an extended period of time).
Float or Slack is the amount of time that a task in a project network can be delayed without causing a delay – Subsequent tasks – (free float) or Project Completion – (total float)
Lead time: the time by which a predecessor event must be completed in order to allow sufficient time for the activities that must elapse before a specific event is reached to be completed.
Lag time: the earliest time by which a successor event can follow a specific PERT event.
Slack: the slack of an event is a measure of the excess time and resources available in achieving this event. Positive slack(+) would indicate ahead of schedule; negative slack would indicate behind schedule; and zero slack would indicate on schedule

Total Project Time It is the time taken to complete a project and is found from the sequence of critical activities. In other words it is the duration of the critical path.

Earliest Start Time (EST) The earliest possible time an activity can start, assuming all preceding activities start as early as possible. It is calculated by moving from the first to the last event in a network diagram.

Earliest Finish Time (EFT) It is the earliest possible time at which as activity can finish.

EFT = EST + Duration of that activity

Latest Start Time (LST) It is the latest possible time by which an activity can start.

LST = LFT – Duration of the activity

Latest Finish Time (LFT) It is calculated by moving backwards, that is, from the last event to the first event of the network diagram. It is the last event time of the head event.

Float or Slack Slack is with reference to an event and float is with respect to an activity. This means that slack is used with PERT and float is used with CPM. But when preparing PERT/CPM charts, they may be used interchangeably. Float or slack means spare time, a margin of extra time over and above its duration which a non-critical activity can consume without delaying the project. Float is the difference between the time available for completing an activity and the time necessary to complete the same.

Total Float It is the additional time which a non-critical activity can consume without increasing the project duration. However, total float may affect the floats in previous and subsequent activities and it can also be negative.

Total Float = (LST- EST) OR (LFT- EFT)

Free Float If all the non-critical activities start as early as possible, the spare time is the free float. Free float, if used, does not change the float in later activities. This means that if an activity is delayed by the free float period, the succeeding activity will not by delayed in turn.

Free Float = EST of tail event – EST of head event – Activity duration

Independent Float The use of independent float of an activity does not change the float in other activities. Independent float can be used to advantage if one is interest to reduce the effort on a non-critical activity in order to apply the same on a critical activity thereby reducing the project duration. The independent float associated with an activity is not reduced by delaying previous operations whereas such a reduction can be noticed with free float.

Independent Float = EST of tail event – LFT of head event – Activity duration

Network or Arrow Diagram A network is a graphic view or display of all project activities interrelated through logical or precedence relationships. Networks should begin with one node and end with another node. These diagrams are usually drawn from left to right to show project chronology and they are also called PERT/CPM charts.A PERT/CPM chart is thus a project management tool used to schedule, organize, and coordinate tasks within a project. The chart presents a graphic illustration of a project as a network diagram consisting of numbered nodes (either circles or rectangles) representing events, or milestones in the project linked by labeled directional lines representing tasks in the project. The direction of the arrows on the lines indicates the sequence of tasks.

In Fig. 1, “Tasks” are represented by Arrows, “Events” are circles, “Dummy Tasks” are Dashed Arrows and “Critical Tasks” are Thick Arrows

Steps in PERT/CPM There are six steps involved in PERT/CPM that should be completed in chronological order:

– Identify activities required by the project.

– Identify the precedence relationships among the activities.

– Determine the expected time requirements for each activity.

– Develop a network diagram of activities (arrows) and events or nodes (circles) showing precedence relationships.

– Determine the earliest and latest feasible event times.

– Identify the critical path (the minimum time to complete the project).

Example Let us take an example to explain the steps of PERT/CPM.

Illustration of network analysis of redesigning of an information product and its associated activities including its repackaging are presented below:

The key question is: How long will it take to complete this project?

Activity Number	Activity	Completion time (in weeks)
1	Redesign Information Product	6
2	Seek approval from authorities	2
3	Request for inputs for redesigned product	3
4	Receive inputs for redesigned product	2
5	Assemble details related to redesigned product	4
6	Make up redesigned product	1
7	Finalise the product	1
8	Test the redesigned product	6
9	Revise redesigned product based on feedback	3
10	Present to authorities for approval	1
11	Receive and Circulate to the users	1

Before starting any of the above activity, the questions asked would be:

– What activities must be finished before this activity can start?

– Could we complete this project in 30 weeks?

– Could we complete this project in 2 weeks?

One answer could be, if we first do activity 1, then activity 2, then activity 3, …., then

activity 10, then activity 11 and the project would then take the sum of the activity completion times, 30 weeks.

But the main question is:

“What is the minimum possible time in which we can complete this project?”

For clarity, this list is kept to a minimum by specifying only immediate relationships, that is relationships involving activities that “occur near to each other in time”.

Activity number		Activity number
1	must be finished before	3	can start
2	must be finished before	4	can start
3	must be finished before	5	can start
4	must be finished before	6	can start
5, 6	must be finished before	7	can start
7	must be finished before	8	can start
8	must be finished before	9	can start
8	must be finished before	10	can start
9,10	must be finished before	11	can start

We shall see below how the network analysis diagram/picture we construct helps us to answer this question.

Data Entry Table

Activity No.	Activity Name	Immediate Predecessor	Normal Time (in weeks)

1	1		6
2	2		2
3	3	1	3
4	4	2	2
5	5	3	4
6	6	4	1
7	7	5,6	1
8	8	7	6
9	9	8	3
10	10	8	1
11	11	9,10	1

Calculations for Network

Activity	Activity	On	Activity	Earliest	Earliest	Latest	Latest	Slack/Float
No.	Name	Critical	Time	Start	Finish	Start	Finish	(LST-EST)
		Path		Time	Time	Time	Time
1	1	Yes	6	0	6	0	6	0
2	2	No	2	0	2	8	10	8
3	3	Yes	3	6	9	6	9	0
4	4	No	2	2	4	10	12	8
5	5	Yes	4	9	13	9	13	0
6	6	No	1	4	5	12	13	8
7	7	Yes	1	13	14	13	14	0
8	8	Yes	6	14	20	14	20	0
9	9	Yes	3	20	23	20	23	0
10	10	No	1	20	21	22	23	2
11	11	Yes	1	23	24	23	24	0
Project Completion Time	=	24	Weeks

Number of Critical Path(s)	=	1

CRITICAL PATH TAKES 24 WEEKS FOR THE COMPLETION OF THIS PROJECT.

In the figure 3, the Critical Path is indicated by the blue line.

The critical path is: Activity 1-3-5-7-8-9-11

and, time taken is: 6+3+4+1+6+3+1 = 24 weeks

For items on the critical path, the early days and late days will be the same and there will be no slack time. While working backwards, the late start of a task is the same as the late finish of the previous task or tasks. When there is more than one task with different late starts which is derived from a single task, the earliest late start is used as the late finish of the previous task.

When the PERT chart is completed, the critical path is the tasks without slack time.

From a project management point of view, the tasks on the critical path need to be tracked more closely than the tasks that are not on the critical path. This allows the project manager to focus his or her time with the areas that are most likely to affect the schedule.

The PERT/CPM chart is more complicated than the Gantt chart but it does provide the project manager with more information. The PERT/CPM chart is typically not used in presentations or in meetings due to its complexity. Presently, project management tools such as Microsoft Project can be used to show both the Gantt and the PERT/CPMview so a project manager would not necessarily need to make two separate diagrams.

– Useful at many stages of project management

– Especially useful when controlling large projects

– Mathematically simple

– Give critical path and slack time

– Provide project documentation

– Useful in monitoring both the schedules as well as the costs

Limitations in PERT/CPM Technique

– Project activities have to be clearly defined, independent and stable in their relationships

– Precedence relationships must be specified and networked together

– Over emphasis on critical paths

– Deterministic CPM model

– Activity time estimates are subjective and depend on judgment

– PERT consistently underestimates the expected project completion time due to alternate paths becoming critical

6. Difference between Gantt Charts and PERT/CPM

When creating a project schedule, information managers will find both PERT/CPM and Gantt charts to be essential tools for successfully completing the project at hand. Both types of charts provide tools for managers to analyse projects through visualization, helping divide tasks into manageable parts. Their major differences are discussed below:

Visualization One of the key differences between a PERT/CPM Chart and a Gantt chart is the way the information is presented. Gantt charts present information in the format of a bar chart. This presentation helps show the percentage of work completed for each task. PERT/CPM, on the other hand, displays information as a network model. This means that a PERT/CPM chart presents an initial node from which tasks branch out. This helps project managers visualize the sequence of tasks, as you cannot start on the next activity until the one preceding it is completed.

Work Breakdown Structure One of the key responsibilities of a project manager is to break down the workload into tasks to guarantee that the project will be finished by the deadline. Both PERT/CPM and Gantt charts will display the tasks to be completed, but the charts emphasize different pieces. In Gantt charts, the focus is on the percentage completion of each task, without demonstrating the link that two tasks may have to each other. While PERT/CPM typically does not show the percentage completed, because it employs a network model, it is easy to see which tasks depend on each other.

Simplification Gantt charts are ideal for straightforward projects with few interlinking tasks. Gantt charts present project tasks and time allocation as the only two pieces of data. While this is a limitation where there are interconnecting tasks that depend on each other, for more basic projects it is easier to interpret the data in a Gantt chart. PERT/CPM charts, while also including project tasks and time allocation, display dependency. Gantt charts are easier to change as a task moves along and it comes closer to completion.

Accuracy Gantt charts are simpler to read, but PERT/CPM charts extend an element of detail to the project scheduling through both the network model’s ability to display dependency and PERT/CPM’s unique ability to anticipate actual time that a task will take to completion. Tasks in PERT/CPM charts will have three representative time structures, namely, optimistic, most likely, and pessimistic. By averaging these times, a manager can predict how long a task will actually take to complete more realistically than the single time that Gantt charts provide.

7. Summary

Operational planning is a subset of strategic planning. It describes short-term ways of achieving milestones and explains how, or what portion of, a strategic plan will be put into operation during a given operational period, in the case of commercial application, a fiscal year or another given budgetary term.

In this lesson, we have learnt that an operational plan is necessary to ensure that the activities of the library and its services are focused on achieving the priorities and goals identified in the strategic plan. Information managers should choose an operational management technique/tool that best suits their management style.No one tool addresses all project management needs. The two major techniques discussed in this module are Gantt Charts and Network analysis.

A Gantt chart is a type of bar chart, developed by Henry Ganttthat illustrate a project schedule. Gantt charts illustrate the start and finish dates of the terminal elements and summary elements of a project. Terminal elements and summary elements comprise the work breakdown structure of the project. Some Gantt charts also show the dependency (i.e., precedence network) relationships between activities.

Network analysis is the general name given to certain specific techniques which can be used for the planning, management and control of projects. Two different techniques for network analysis were developed independently in the late 1950’s – these were – PERT (for Program Evaluation and Review Technique); and CPM (for Critical Path Management). In this lesson, these two techniques have been discussed in detail with examples.

Lastly, major differences between Gantt charts and PERT/CPM charts have been discussed.

8. References

1. Arora, Renu. Monitoring and Control Techniques. InMLI-102, Part I, MLIS Course, IGNOU, New Delhi. 2005. P.156-180.

2. Clark, Wallace, Polakov, Walter Nicholas and Trabold, Frank W. The Gantt Chart: A Working Tool of Management. New York: Ronald Press Co. 1922

3. Punmia, B. C. and Khandelwal K. K.Project Planning and Control with PERT & CPM. E-book @ http://theijes.com/papers/v2-i1/Y02101540159.pdf

4. Richman, Larry. Successful Project Management, 3r d ed. New York: AMACOM. 2011

5. Sharma, S C. Operation Research: Pert, Cpm& Cost Analysis. New Delhi: Discovery Publishing House, 2006.

Learn More:

DID YOU KNOW

Inpractice, project managers use software tools like Microsoft Project to create Gantt Charts and CPA Charts. Not only do these make them easier to draw, they also make modification of plans easier and provide facilities for monitoring progress against plans.

INTERESTING FACTS

No.	Interesting Facts
1.	Also known as a network diagram, the PERT chart was first used in the late 1950s by the U. S. Navy while working on the Polaris missile project during the Cold War era.
2.	Although Gantt charts and PERT charts are often used hand-in- hand, Gantt chart actually predates the PERT chart by almost 40 years. However,despite being used earlier, the Gantt chart did become more popular during the 1950s, at about the same time the first PERT charts were implemented.
3.	While both PERT and Critical Path Method came into existence at about the same time, the two methodologies were actually developed independently of one another

Web Links

http://en.wikipedia.org/wiki/Gantt_chart

http://searchsoftwarequality.techtarget.com/definition/Gantt-chart

https://www.smartsheet.com/s/online-gantt-chart?

https://www.scss.tcd.ie/~yoonj/Teaching/ST4004/CPM_Reading3.pdf

http://www.interventions.org/pertcpm.html