Time Management

Project Time Management

By

Eng. Ashraf Bahaa, PMP

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Ashraf Bahaa, PMP – Jan 2003

1.0 Time Management

For most people, time is a resource that, when lost or misplaced, is gone forever. Fora project manager, time is more of a constraint, and effective time managementprinciples must be employed to make it a resource.Inexperienced project managers often work large amount of overtime, with the faultynotion that this is the only way to get the job done. While this may be true, experiencedpersonnel soon learn to delegate tasks and to employ effective time managementprinciples.

In Mar/Apr 1981, a survey was conducted of more than 300 project managers in 24different industries to identify the problems that exist in trying to obtain effective timemanagement. The survey was conducted with written questionnaires and personalinterviews. Fifteen areas were investigated:

- Employee's background - Energy cycle per day- Energy cycle per week - Daily/weekly work schedule- Overtime - Productivity- Meeting - Time Robbers- Time away from desk - Priorities- Communications - Conflict management- Planning/re-planning - Community service- Delegation

Project managers typically understand the role of the project manager at projectconception, but seem to forget it during project execution. Project managers mustunderstand that even through they have the authority, responsibility, and accountabilityfor a project, there are still parent company administrative duties that must beaccepted. These items are usually additional work that the project manager has notconsidered.

1.1 Planning

The most important responsibilities of a project manager are planning, integrating, andexecuting plans. Planning, in general, can best be described as the function ofselecting the enterprise objectives and establishing the policies, procedures, andprograms necessary for achieving them.The project manager is the key to successful project planning. It is desirable that theproject manager be involved from project conception through execution.Project planning must be systematic, flexible enough to handle unique activities,disciplined through reviews and control, and capable of accepting multifunctionalinputs. Successful project manager realized that project planning is an iterativeprocess and must be performed throughout the life of the project.Planning is determining WHAT needs to be done, by WHOM, and by WHEN, in orderto fulfill one's assigned responsibility.Planning is the process of preparing for the commitment of resources in the mosteffective fashion.





There are four reasons for project planning:1. To eliminate or reduce uncertainty.2. To improve efficiency of the operation.3. To obtain a better understanding of the objectives.4. To provide a basis for monitoring and controlling work.

There are nine major components of the planning phase:1. Objective: a goal and a target to be achieved by a certain time.2. Program: The strategy to be followed and a major action to be taken in order to

achieve or exceed objectives.3. Schedule: a plan showing when individual or group activities or

accomplishments will be started and/or completed.4. Budget: Planned expenditures required to achieve or exceed objectives.5. Forecast: a projection of what will happen by a certain time.6. Organization: design of the number and kinds of positions, along with

corresponding duties and responsibilities, required to achieve or exceedobjectives.

7. Policy: a general guide for decision making and individual actions.8. Procedure: a detailed method for carrying out a policy.9. Standard: a level of individual or group performance defined as adequate or

acceptable.

The contractor plans for the work in two stages:

♦ Pretender Planning :The planning undertaken by the contractor after receipt of tender notice and beforesubmitting a bid. It enables the contractor to make a proper bid and prepares him fortaking up the work speedily, in case his bid is successful.

♦ Contract Planning :After the tender has been accepted, the contractor has to undertake further intensiveplanning. It aims at organization all aspects of construction job so that the work mayproceed without any interruptions or delay.

The scheduling of activities is the first major requirement of the program office afterprogram go-ahead. Activity scheduling is probably the single most important tool fordetermining how company resources should be integrated so that synergy isproduced.





1.2 Preparation sequence for schedules and program plans

Detailed schedules are prepared for almost every activity. It is the responsibility of theprogram office to marry all of the detailed schedules into one master schedule to verifythat all activities can be completed as planned. The program office submits a requestfor detailed schedules to the functional managers. The request may be in the form of aplanning work authorization document. The functional managers then preparesummary schedules and detailed schedule. Each functional manager then reviews hisschedules with the program office. The program office, together with the functionalprogram team members, integrates all of the plans and schedules and verifies that allcontractual dates can be met. Before the schedules are submitted to publications,rough drafts of each schedule and plan should be reviewed with the customer. Afterthe document is published, it should be distributed to all the program office personnel,functional team members, functional management, and the customer.

Contractor Program Office

Functional Management

SupervisePreparation

Program Team Managers Customer Office

Verify that allfunctional plans are

integrated

CustomerReview

Prepare PlansDistribution

Publications

Request fordetailed

schedule & plansLevel 3

FunctionalManagement

Review

IndividualReviews

ProgramTeam

ReviewVerification Rough

DraftsFinalizePlans /

Schedules

1

2 3

4 5 6 7 89

10

Dept. / Section Level





2.0 Scheduling Techniques

Scheduling techniques have taken on paramount importance since World War II. Themost common techniques are:

♦ Gantt or Bar Charts.♦ Milestone Charts.♦ Line of Balance♦ Networks

• Program Evaluation and Review Technique (PERT)• Critical Path Method (CPM)• Arrow Diagram Method (ADM)• Precedence Diagram Method (PDM)• Graphical Evaluation and Review Technique (GERT)

2.1 Gantt (Bar) Chart

The most common type of display is the Gantt or Bar Chart, named for Henry Gantt,Who first utilized this procedure in the early 1900s. The bar chart is a means ofdisplaying simple activities or events plotted against time or dollars. An activityrepresents the amount of work required to proceed from one point in time to another.Events are described as either the starting or ending point for either one or severalactivities.Bar charts are advantageous in that they are simple to understand and easy tochange. Bar Charts are most commonly used for exhibiting program progress ordefining specific work required to accomplish an objective.The primary advantage of the bar chart is that plan, schedule, and progress of theproject can all be portrayed graphically together.





2.2 Milestone (Master) Schedule

A summary-level schedule, which identifies the major milestones.

2.3 Development of the network plan concept:

The Major discrepancy with Gantt and Milestone Charts is the inability to show theinterdependencies between events and activities. Interdependencies are shownthrough the construction of networks. The heart of network-based planning methods isgraphical portrayal of the plan for carrying out the program. Such a graph, called anetwork, shows the dependency relationship among the project activities using thesimple logic that all activities preceding a given activity must be completed before thegiven activity may begin. The prime purpose of network planning is to eliminate theneed for crisis management by providing a pictorial representation of the totalprogram. The major use of project networks is scheduling-determining how long theproject will take (Project Duration) and when each activity should be scheduled.

2.4 Network Fundamentals:

Networks are composed of events and activities. An event is defined as the starting orending point for a group of activities, and an activity is the work required to proceedfrom one event or point of time to another.The standard nomenclature for a network is consisting of Node and Arrow.

2.4.1 Types of networks

Arrow Diagram Method (ADM) or Activity-on-Arrow (AOA)In case of ADM: the node represents an event and the arrow represents an activity.

Event EventActivity

NodeNode

Arrow





Precedence Diagram Method (PDM) or Activity-on-Node (AON)In case of PDM: the node represents an Activity and the arrow represents aRelationship.

Activity A is predecessor of activity BActivity B is successor of activity AA < B or B > A

ActivityA

ActivityB

Relationship

Predecessor Successor

Activity ActivityRelationship

NodeNode

Arrow

Activity A1 2

Predecessor Successor

Activity B3





2.5 Dummy activity:

Sometimes, it is impossible to draw network dependencies without including dummyactivities. Dummy activities are artificial activities, represented by a dotted line, and donot consume resources or require time. They are added into the network simply tocomplete the logic.

Example

A < C B < E C < D, E

A

B

3

2

4

5

CD

E X

1

a

A

B

2

4

5

CD

E

1

3

DummyActivity





2.6 The Critical Path

The expected project duration is determined by finding the longest path through thenetwork. A path is any route comprised of one or more activities connected insequence. The longest path from the origin node to the terminal node is called thecritical path; this gives the expected project duration.

The bold line in the shown network represents the critical path, which is established bythe longest time span through the total system of events. The critical path is composedof events 1-2-5-6. The critical path is vital for successful control of the project becauseit tells management two things:Because there is no float time in any of the events on this path, any slippage will causea corresponding slippage in the end date of the project unless this slippage can berecovered during any of the downstream events on the critical path.Because the events on this path are the most critical for the success of the project,management must take a hard look at these events in order to improve the totalproject.

The path is called critical in the sense that, should it be necessary to reduce theproject completion time, the reduction would have to be made by shortening activitieson the critical path. Shortening any activity on the critical path by, say one week, wouldhave the effect of reducing the project duration by one week. In contrast, shorteningactivities not on the critical path has no effect on project duration.

A

B

2

5

6

C

D

F

1

4

G3

3

7

36

2

55

E

TE = 0TL = 0

TE = 3TL = 3

TE = 2TL = 5

TE = 6TL = 9

TE = 10TL = 10

TE = 15TL = 15





2.7 Slack Time

Since there exists only one path through the network that is the longest, the otherpaths must be either equal in length to or shorter than that path. Therefore, there mustexist events and activities that can be completed before the time when they areactually needed. The time differential between the schedule completion date and therequired date to meet critical path is referred to as the slack time.Slack can be defined as the difference between the latest allowable date and theearliest expected date based on the nomenclature below:

TE = the earliest date on which an event can be expected to take place.TL = the latest date on which an event can take place without extending the completion

date of the project.

Slack time = TE - TL

The calculation of slack time is not difficult. For complex networks containing multiplepaths, the earliest starting dates must be found by proceeding from start to finishthrough the network (Forward), while the latest allowable starting date must becalculated by working from finish to start (Backward).

Some people prefer to calculate the earliest and latest times for each activity.ES = the earliest time when an activity can start.EF = the earliest time when an activity can finish.LS = the latest time when an activity can start.LF = the latest time when an activity can finish.To calculate the earliest starting times, we must make a forward pass through thenetwork (from left to right). The earliest starting time of a successor activity is the latestof the earliest finish dates of the predecessors. The latest starting time is the total ofthe earliest starting time and the activity duration.To calculate the finishing times, we must make a backward pass through the network(from right to left) by calculating the latest finish time. Since the activity time is known,the latest starting time can be calculated by subtracting the activity time from the latestfinishing time. The latest finishing time for an activity entering a node is the earliestfinishing time of the activities exiting the node?

Activity ID (ES, EF)

Duration (LS, LF)





2.8 Origin and use of PERT

PERT was developed by the U.S. Navy during the late 1950s to accelerate thedevelopment of the Polaris Fleet Ballistic Missile. The development of this weaponinvolved the coordination of the work of thousands of private contractors and othergovernment agencies. The coordination with PERT was so successful that the entireproject was completed 2 years ahead of schedule. This has resulted in furtherapplications of PERT in other weapons development program in the Navy, Air Force,and Army. At the current time, it is extensively used in industries and other serviceorganization as well.

The time required to complete the various activities in a research and development(R&D) project is generally not known a priori. Thus, in its analysis PERT incorporatesuncertainties in activity times. It determines the probabilities of completing variousstages of the project by specified deadlines, and also calculates the expected time tocomplete the project. An important and extremely useful by product of PERT analysisis its identification of various "Bottlenecks" in the project. In other words, it identifiesthe activities that have high potential for causing delays in completing the project onschedule. Thus, even before the project has started, the project manager knows whereto expect delays. He can take the necessary preventive measures to reduce possibledelays so that project schedule is maintained.Because of its ability to handle uncertainties in job times, PERT is extensively used inresearch and development projects.

2.9 Origin and use of CPM

The critical path method closely resembles PERT in many aspects but developedindependently by E.I. du Pont de Nemours Company in the period 1956-1959. As amatter of fact, the two techniques, PERT and CPM, were developed almostsimultaneously. The objective of the CPM research team was to determine how best toreduce the time required to perform routine plant overhaul, maintenance, andconstruction work.

The major difference between CPM and PERT is that CPM dose not incorporateuncertainties in job times. Instead, it assume that activity times are proportional to theamount of resources allocated to them, and that by changing the level of resources theactivity times and the project completion time can be varied. Thus, CPM assumes priorexperience with similar projects from which relationship between resources and jobtimes are available. CPM then evaluates the trade-off between project cost and projectcompletion time.

CPM is mostly used in construction projects were one has prior experience in handlingsimilar projects.

PERT and CPM techniques are similar in that they divide project into manageableactivities and identify those that are critical to project completion, that is, those where avariation in time affects project completion. All other activities are not critical.





The basic elements of both PERT and CPM are:♦ Network diagram.♦ Critical path through the network.

The differences between PERT and CPM are

PERT CPM

Uses three times estimates to eachactivity

Uses one time estimate (Normal time)for each activity

Probabilistic in nature Deterministic in nature

Used for R&D projects Used for construction projects

Percent complete is almostimpossible to determine except atcompleted milestones

Percent complete can be determinedwith reasonable accuracy andcustomer billing can be accomplishedbased on percent complete.

The basic difference between PERT and CPM lies in the ability to calculate percentcomplete. PERT is used in R&D projects or just development activities, where apercent complete determination is almost impossible. Therefore, PERT is eventoriented rather than activity oriented. In PERT, funding is normally provided for eachmilestone (event) achieved. CPM, on the other hand, is activity oriented because, inactivities such as construction, percent complete along activity line can be determined.The CPM has been widely used in the process industries, in construction, and insingle-project industrial activities.

2.10 Graphical Evaluation and Review Technique (GERT)

Graphical evaluation and review technique (GERT) are similar to PERT but have thedistinct advantages of allowing for looping, branching, and multiple project end results





3.0 Program Evaluation and Review Technique (PERT)

3.1 Estimating activity time

We computed the Critical Path and slack times using best estimates for activityduration times. Instead of using one estimate for activity duration, PERT addressesuncertainty in the duration by using three time estimates {Optimistic, Most Likely, andPessimistic}. These estimates are then used to calculate the "expected time" for anactivity.

♦ The Optimistic Time: (a) is the minimum time an activity could take (thesituation, where every thing goes well) There should be little hope offinishing before this time.

♦ The Most Likely Time: (m): is the normal time to complete the job. It is thetime would occur most frequently if the activity could be repeated.

♦ The Pessimistic Time: (b): is the maximum time an activity could take (thesituation, where bad luck is encountered at every step. The adverseconditions include mechanical breakdowns, minor labour troubles, andshortage of or delays in delivery of material.

The estimates are obtained from the most qualified people, expert estimators or thosewho will actually perform or manage the activity. They should be the people mostknowledgeable about difficulties likely to be encountered and about the potentialvariability in time.The three estimates are related in the form of a Beta probability distribution withparameters a and b as the end points, and m the modal, or most frequent.

Activity duration time

Probabilityoftime

Optimistic(a)

Pessimistic(b)

MostLikely(m)

Expected(t e)

BetaDistribution





Based on this distribution, the mean or expected time te and the variance ?�2 of eachactivity are computed with the three time estimates:

te = a + 4m + b6

2

?¦2 = b – a

6

The expected time te represents the point on the distribution where there is a 50/50chance that the activity will be completes earlier or later than it.

The variance ?22 : is a measure of variability in the activity completion time.

Example:

Duration (week) VarianceActivity A m B te ?á2

1-2 5 11 11 10 11-3 7 7 7 7 02-4 3 5 13 6 2.783-4 2 9 10 8 1.78

Critical Path: 1-2-3-4: 18 weeksVariance ?¢2 = 1+1.78 = 2.78Standard deviation ?Ú= (2.78)½ = 1.67

7

2

4

10

1

3

6

8





3.2 Probability of completion the project

The expected duration of the project Te is the sum of the expected duration of theactivity in the critical path. The project duration in PERT is not a single estimate but anestimate subject to uncertainty owing to the uncertainties of the activity times along thecritical path . Thus, the project duration can be thought of as a probability distributionwith an average of Te. So the probability completing the project prior to Te is less than50 %, and the probability of completing it later than Te is greater than 50 %.The distribution of project durations Te's, is approximated using the familiar bell-shape,normal distribution. Giving this assumption, the probability of meeting any targetproject completion date Ts which dose not coincide with the expected date Te can bedetermined.

Normal Distribution

Standard normal distribution for µ = 0 and σ = 1

Z = (x – µ) / σ

Probability of completing the project in less than Te = 50%Probability of completing the project in more than Te = 50%Probability of completing the project in exactly Te = 0%Probability of completing the project in (Te -1σ) to (Te +1σ) = 68%Probability of completing the project in (Te -2σ) to (Te +2σ) = 95%Probability of completing the project in (Te -3σ) to (Te +3σ) = 99.7%

ProbabilityP(x)

µ−�σ �σ−�σ−�σ �σ �σ





Probability of completing the project in less than (Te +1σ) = 84%Probability of completing the project in more than (Te +1σ) = 16%Probability of completing the project in less than (Te + 2σ) = 97.5%Probability of completing the project in more than (Te +2σ) = 2.5%Probability of completing the project in less than (Te + 3σ) = 99.85%Probability of completing the project in more than (Te + 3σ) = 0.15%

3.3 Case Study

Duration (week) VarianceActivity

a m B te ?á2

1-2 1 1 7 2 11-3 1 4 7 4 11-4 2 2 8 3 12-5 1 1 1 1 03-5 2 5 14 6 44-6 2 5 8 5 15-6 3 6 15 7 4

2

4 6

1

1

5

3

2

7

3

64

5

TE = 0TL = 0

Slack = 0

TE = 2TL = 9

Slack = 7 TE = 10TL = 10

Slack = 0

TE = 3TL = 12

Slack = 9

TE = 4TL = 4

Slack = 0

TE = 17TL = 17

Slack = 0





The critical path: 1-3-4-6The expected project time = 17 weeksVariance ?<2 = 9Standard Deviation σ = 3

The probability that the project will be completed at least 3 weeks earlier thanexpected:Z = (x – µ) / σ

Z = (14 – 17) / 3 = -1The probability = 16%

The probability that the project will be completed no more than 3 weeks later thanexpected:Z = (x – µ) / σ

Z = (20 – 17) / 3 = 1The probability = 84%

If the project due date is 18 weeks:The probability of meeting the due date:Z = (x – µ) / σZ = (18 – 17) / 3 = 0.33The probability = 37.07%The probability of not meeting the due date = 62.93%

For probability 90%Z = 1.28Z = (x – µ) / σ1.28 = (x – 17) / 3x = 20.84 weeks





4.0 Precedence Networks

An important extension to the original activity-on-node concept appeared around 1964in the Users Manual for an IBM 1440 computer program. One of the principal authorsof the technique was J. David Craig, who referred to the extended node scheme as"precedence diagramming". The computation and interpretation of early/latestart/finish times for project activities for this scheme is considerable more complexthan those shown for the basic finish-to-start constraint logic of arrow or nodediagrams. The computation and interpretation of these times was both simple andunique.The basic computational approach to be used in this text is to adopt a procedure thatwill lead to activity early/late start/finish times for a precedence diagram network thatare identical to those that would be obtained for the equivalent arrow diagram and theconventional forward and backward pass computations.The computational procedure to be given here is based on an extension of thePERT/CPM network logic from a single finish-to-start type of dependency to includethree other types. The other dependency relationships are presented in figure below.

Activity(1)

Activity(2)

Activity(1)

Activity(2)

Activity(1)

Activity(2)

Activity(1)

Activity(2)

(A) Finish-To-Start

(B) Start-To-Start

(C) Finish-To-Finish

(D) Start-To-Finish

SS12

FF12

SF12

FS12





The arrow represents the relationship between activity (1) and activity (2) which arerelated activities in network

(A) Finish-To-Start: FS12: is equal to the minimum number of time unitsthat must transpire from the completion of the predecessor {activity (1)}prior to the start of the successor {activity (2)}. This is the sole logicconstraint used in PERT/CPM with FS12 = 0

(B) Start-To-Start: SS12: is equal to the minimum number of time units thatmust be completed on the predecessor {activity (1)} prior to the start ofthe successor {activity (2)}.

(C) Finish-To-Finish: FF12: is equal to the minimum number of time unitsthat must remain to be completed on the successor {activity (2)} afterthe completion of the predecessor {activity (1)}.

(D) Start-To-Finish: SF12: is equal to the minimum number of time unitsthat must transpire from the start of the predecessor {activity (1)} to thecompletion of the successor {activity (2)}.

The figure below show the typical information that appears in each of the activityboxes (nodes)

Activity Duration Activity ID Total Float (Slack)

Activity Description

Early StartES

Late StartLS

Early FinishEF

Late FinishLF

4.1 Lag

The time period between the early start or finish of one activity and the early start orfinish of another activity in the sequential chain. Lag is most commonly used inconjunction with precedence networks.





4.2 Precedence diagram computational procedures

Obviously the forward and backward pass computational problem becomes morecomplex with precedence diagramming. In the computational procedures we willassume that the specified activity durations are fixed and the activity splitting is notallowed on any activities.

4.2.1 Forward pass computations

The following two steps are applied to each project activity. The term called Initial Timeis set equal to zero or to an arbitrarily specified project schedule start time.

Step 1: Compute ES2, the early start time of the activity (2). It is the maximum (latest)of the set of start times which include the Initial Time, and one start time computedfrom each constraint going to the activity (2) from predecessor activities indexed by (1)

Initial TimeEF1 + FS12

ES2 = Max1 ES1 +SS12EF1 + FF12 – D2ES1 + SF12 – D2

Step 2: EF2 = ES2 + D2

4.2.2 Backward pass computations

The following two steps are applied to each project activity in the reverse order of theforward pass computations. The term called Terminal Time is set equal to the projectduration or to an arbitrarily specified project schedule completion time.

Step 1: Compute LF1, the late finish time of the activity (1). It is the minimum (earliest)of the set of finish times which include the terminal Time, and one finish timecomputed from each constraint going to the activity (1) to successor activities indexedby (2)

Terminal TimeLS2 - FS12

LF1 = Min2 LF2 - FF12LS2 - SS12 + D1LF2 - SF12 + D1

Step 2: LS1 = LF1 – D1





4.3 Total Slack (Total Float)

The Es and Ls (EF and LF) are not always the same at each activity. The differencebetween ES and LS is referred to as total slack (float) TF. Slack is the range ofallowable variation between when an activity can be scheduled and when it must bescheduled for the project to complete on target.

Total Slack (Float) = LS – ESTotal Slack (Float) = LF – EF

The total slack for activities on the critical path is ZERO, meaning that a delay in any ofthe critical activities would delay the project. One reason why the longest path is calledthe "critical" path is because, besides being the longest path, slack along the criticalpath is always the smallest slack of any where in the project. Activities not on thecritical path (non critical activities) can be delayed by their amount of total slackwithout affecting the completion date and the total slack is the maximum time they canbe delayed, once their total slack time is used up, non critical activities become criticaland further delays will delay the project completion date.

4.4 Free Slack (Free Float)

Some non critical activities can be delayed without affecting the slack of successoractivities. The term Free Slack (Float) FF is used to refer to the amount of time anactivity can be delayed without affecting the start time of any successor activities.

Free Slack (Float) = ES earliest successor – EF predecessor





4.5 Case Study:

Forward pass computation:

Activity (A):ESA = { INITIAL TIME = 0 } = 0EFA = ESA + DA = 0 + 8 = 8

Activity (B):ESB = MaxA { INITIAL TIME = 0 }

{ ESA + SSAB = 0 + 3 = 3 } = 3{ EFA + FFAB - DB = 8 + 4 - 12 = 0 }

EFB = ESB + DB = 3 + 12 = 15

Activity (C):ESC = MaxB { INITIAL TIME = 0 }

{ ESB + SSBC = 3 + 6 = 9 } = 9EFC = ESC + DC = 9 + 4 = 13

Activity (D):ESD = MaxB { INITIAL TIME = 0 }

{ EFB + FSBD = 15 + 0 = 15 } = 15EFD = ESD + DD = 15 + 6 = 21

Activity (E):ESE = MaxC,D { INITIAL TIME = 0 }

{ EFC + FSCE = 13 + 0 = 13 } = 21{ EFD + FSDE = 21 + 0 = 21 }

EFE = ESE + DE = 21 + 6 = 27

Activity (F):ESF = MaxD { INITIAL TIME = 0 }

{ ESD + SFDF - DF = 15 + 15 - 12 = 18 } = 18EFF = ESF+ DF = 18 + 12 = 30





Backward pass computation:

Activity (F):LFF = { TERMINAL TIME = 30 } = 30LSF = LFF - DF = 30 - 12 = 18

Activity (E):LFE = { TERMINAL TIME = 30 } = 30LSE = LFE - DE = 30 - 6 = 24

Activity (D):LFD = MinE,F { TERMINAL TIME = 30 }

{ LSE - FSDE = 24 - 0 = 24 } = 21{ LFF - SFDF + DD = 30 - 15 + 6 = 21 }

LSD = LFD - DD = 21 - 6 = 15

Activity (C):LFC = MinE { TERMINAL TIME = 30 }

{ LSE - FSCE = 24 - 0 = 24 } = 24LSC = LFC - DC = 24 - 4 = 20

Activity (B):LFB = MinC,D { TERMINAL TIME = 30 }

{ LSC - SSBC + DB = 20 - 6 + 12 = 26 } = 21{ LSD - FSBD = 15 - 0 = 15 }

LSB = LFB - DB = 15 - 12 = 3

Activity (A):LFA = MinB { TERMINAL TIME = 30 }

{ LFB - FFAB = 15 - 4 = 11 } = 8{ LSB - SSAB + DA = 3 - 3 + 8 = 8 }

LSA = LFA- DA = 8 - 8 = 0





5.0 Resource Management

Each activity in a network may have some form of resource associated in itsexecution. Typically, these are manpower, machine (equipment), material, and money(financial). In developing a program of work, its duration and the amount of resourcesit requires are totally dependent on each other. The next step is to consider the totaldemand for key resources. So far we have assumed that the requirements of eachindividual activity can be met but, when considering the project or contract as whole,there will be competition between activities and the demand may either exceed theplanned availability of resources or produce a fluctuating pattern for their use.Two techniques : resource smoothing and resource leveling are available for themanipulation of resource demands. In both cases, it is essential to realize that this is acomplex process and therefore only selected key resources should be considered.Manual adjustment can be attempted for small programs but schemes of 50 activitiesor more will normally require the use of a computer software.

5.1 Resource Loading

The discussion of work scheduling has assumed implicitly that any resources neededto do the work would always be available. The only schedule restriction was thatpredecessor activities must be completed first. A different, additional restriction willnow be considered: constrained resources.While many resources are available in sufficient quantity so as not to pose schedulingproblems, all resources are finite and many are scarce. In many cases, limitedavailability of skilled labor, equipment, and material dictate that activities must bescheduled at times other than the early or even late start date.In most situations, the resources available are limited, and it is obviously essential tosee that the resources required are never greater than those available. Critical pathanalysis, while not resolving this situation uniquely, provides useful assistance inachieving an acceptable solution, since it shows which activities can be moved withoutincreasing the total project time, and also the effect of moving time-limited activities.This type of manipulation can be very difficult if there are a large number of activitiesand a large number of resources, as the number of possible moves increasesfactorially with the number of activities. To allow a systematic procedure to befollowed, a set of decision rules must be generated. These rules, which will differ fromorganization to organization, will not necessarily produce a best or optimum solution,but they will tend to produce feasible or workable solutions in a reasonable time.





1

3 6

0 2

Dur = 4Res = 9

4

7

8

9

5

Dur = 2Res = 3

Dur = 2Res = 6

Dur = 2Res = 4

Dur = 3Res = 1

Dur = 3Res = 8

Dur = 2Res = 7

Dur = 3Res = 2

DummyStart

DummyEnd





5.2 Resource Leveling

In many project scheduling situations, the total level of resource demands projected fora particular schedule by the resource loading diagram may not be of major concernbecause ample quantities of the required resources are available. But it may be thatthe pattern of resource usage has undesirable features, such as frequent changes inthe amount of a particular manpower skill category required. Resource levelingtechniques are useful in such situations; they provide a means of distributing resourceusage over time to minimize the period-by-period variations in manpower, equipment,or money expended. They can also be used to determine whether peak resourcerequirements can be reduced with no increase in project duration.

As this simple example shows, the essential idea of resource leveling centers aboutthe rescheduling of jobs within the limits of available float to achieve better distributionof resource usage. The float available in each activity is determined from the standardCPM calculations.When applying resource leveling to the activities that constitute a network, the authorvisualizes the network as a flexible framework that can be pushed and pulled in orderto change its shape. Imagine this network superimposed onto a horizontal time axisand a vertical scale of resource availability. If unlimited resources are provided, theoverall duration will be the critical path duration the minimum time to complete all thework with the given logic and activity durations and resource demand is likely to bevery uneven. If resource levels are reduced, the network will be squashed and, oncethe available float is absorbed, the time scale must then be extended.





6.0 Project crashing

It is often true that the performance of some or all activities can be accelerated by theallocation of more resources at the expense of the higher activity direct cost. Whenthis is so, there are many different combinations of activity durations that will yieldsome desired schedule duration. However, each combination may yield a differentvalue of total project cost. Time/Cost trade-off procedures are directed at determiningthe least-cost schedule for any given project duration.Each activity can be performed at different duration ranging from an upper "Normal"value, at some associated "Normal" cost, down to a lower, "Crash" value, with anassociated higher cost. The cost of intermediate activity durations between the normaland crash durations is easily determined from the single cost "Slope" value for eachactivity.

Activity Duration ES EF LS LF TF CP0-1 4 0 4 0 4 0 *0-2 8 0 8 2 10 21-2 6 4 10 4 10 0 *1-4 9 4 13 6 15 22-3 4 10 14 15 19 52-4 5 10 15 10 15 0 *3-5 3 14 17 19 22 54-5 7 15 22 15 22 0 *

Cost Slope =

(Crash Cost – Normal Cost) / (Normal Duration – Crash Duration)

1

3

5

F

0

4

2

4

6

9

38

4

5

7





Normal Crash

Duration Cost Duration CostCostSlopeActivity

Days L.E Days L.E L.E0-1 4 210 3 280 700-2 8 400 6 560 801-2 6 500 4 600 501-4 9 540 7 600 302-3 4 500 1 1100 2002-4 5 150 4 240 903-5 3 150 3 150 04-5 7 600 6 750 150

Total 3050 4280

If all activity durations are set at "Normal" values, the project duration is 22 days, asdetermined by the critical path (CP) 0-1-2-4-5. The associated cost of projectperformance is 3050 L.E; this cost could be increased to 3870 L.E throughunintelligent decision-making by crashing all activity not on the critical path with nodecrease in project duration. Between these upper and lower cost values for projectduration of 22 days there are several other possible values, depending upon thenumber of non-critical activities crashed.If all activity durations are set at "Crash" values, the project duration can be decreasedto 17 days, with total cost of 4280 L.E. Duration of 17 days can also be achieved atlower cost by not crashing activities unnecessarily. With all other activities set at crashvalue, the associated cost of performance for 17 days project duration is reduced to3520 L.E. This value is the lowest possible value for 17 days project duration.

3050

3870

3520

33703270

3150 3100

40803970

3920

42104280

2500

3000

3500

4000

4500

16 17 18 19 20 21 22 23

Days

Cost

All normalpoint

Crash allexcept CP

All crashpoint

Line ofmin. cost

Line ofmax. cost

Region of possible costs





7.0 Project Control

Controlling is a three-step process of measuring progress toward an objective,evaluating what remains to be done, and taking the necessary corrective action toachieve or exceed the objectives.These three steps: measuring, evaluating, and correcting are defined as follows:

♦ Measuring: determining through formal and informal reports the degree towhich progress toward objectives is being made.

♦ Evaluating: determining cause of and possible ways to act on significantdeviations from planned performance.

♦ Correcting: taking control action to correct an unfavorable trend or to takeadvantage of an unusually favorable trend.

The project manager is responsible for ensuring the accomplishment of group andorganizational goals and objectives. To affect this, he must have a thoroughknowledge of standards and cost control policies and procedures so that a comparisonis possible between operating results and pre-established standards. The projectmanager must then take the necessary corrective actions.

Objectives

Planning

Execution

Results

CorrectiveActions

Followup&

Monitoring





The requirements for an effective control system should include:♦ Through planning of the work to be performed to complete the project.♦ Good estimating of time, labor, and costs.♦ Clear communication of the scope of required tasks.♦ A disciplined budget and authorization of expenditures.♦ Timely accounting of physical progress and cost expenditures.♦ Periodic re-estimation of time and cost to complete the remaining work.♦ Frequent, periodic comparison of actual progress and expenditures to

schedule and budgets, both at the time of comparison and at projectcompletion.

Management must compare the time, cost, and performance of the program to thebudgeted time, cost, and performance, not independently but in an integrated manner.All three parameters (time, cost, and performance) must be analyzed as a group.

♦ The first purpose of control therefore becomes a verification processaccomplished by the comparison of actual performance to date with thepredetermined plans and standards set forth in the planning phase.

♦ The second purpose of control is that of decision making.

Control provides an organization with ways to :♦ Adapt to environment change.♦ Limit the accumulation of error.♦ Cope with organizational complexity.♦ Minimize costs.

There are three reports are required by management in order to make effective andtimely decisions:

♦ Status reporting: describing where the project now stands.♦ Progress reporting: describing what the project team has accomplished.♦ Forecasting: predicting future project status and progress.

Three useful results arise through the use of these reports, generated during athorough decision-making stage of control:

♦ Feedback to management, the planners, and the doers.♦ Identification of any major deviations from the current program plan, schedule,

or budget.♦ The opportunity to initiate contingency planning early enough that cost,

performance, and time requirements can undergo corrected action withoutloss of resources.

One way to increase the effectiveness of control is to fully integrate planning andcontrol. The control system should be flexible, accurate, timely, and as objective aspossible. Employees may resist organizational controls if they feel over-controlled, ifthey think that control is inappropriately focused, if they are being rewarded forinefficiency, or if they desired to avoid accountability. Managers can overcome thisresistance by improving the effectiveness of control and by allowing employeeparticipating and developing verification procedures.





References

Adel El-Shabrawy “The professional program in project management” PM10 ProjectPlanning and Control Techniques, Oct. 1997 / AUC

E.F.L.Brech “Management Its Nature and Significance” 4th Edition 1967

Frank T. Anbari "Quantitative Methods for Project Management" International Institutefor Learing (IIL), 1997

Gamal Nassar “The professional program in project management” Dec. 1990 / AUC

Harold Kerzner “Project Management A System Approach to Planning, Scheduling,and controlling” 6th Edition 1997.

Keith Lockyer "Production Management" 4th Edition 1983

Mohamed Fahmy Hassan "Project Planning & Control" Center of advancement ofpost-graduate studies in engineering sciences – Faculty of Engineering, CairoUniversity.

Osama Hosny “The professional program in project management” PM20Management of Project Resources, Oct. 1997 / AUC

PMI. A Guide to the Project Management Body of Knowledge (PMBOK Guide) 2000Edition. Project Management Institute, 130 South State Road, Upper Darby, 2000

Ricky W.Griffin “Management” 5th Edition 1996

R.S.Dwivedi "Manpower Management" An Integrated approach to personnelmanagement and labour relation – New Delhi 1980

S.A.Sherlekar "Business Administration and Management" 1st Edition 1979

