MS Projects Day 3 Final

7/29/2019 MS Projects Day 3 Final

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Computer based Project ManagementUsing MS Project 2010

Training program on

Day 3




Tasks Dependencies

A task dependency is the relationship between two tasks, in which the start or finish date of one task depends on the start or finish date of another. The task

whose start or finish date depends on another task is called the successor. Thetask that the successor is dependent upon is the predecessor. The mostcommon task dependency is a finish-to-start dependency. In this type of dependency, the second task in the relationship starts when the first task isfinished.




Lead and lag time

Overlapping linked tasks means that you want the successor task to begin beforethe predecessor task ends. Therefore, you give the successor task lead time. Leadtime can be entered as a duration. When you are entering lead time for a task,make sure it is a negative (-) value.

Working with lag time is like working with lead time, except that lag time is apositive value. It can be entered as a duration.




WBS Coding

WBS codes provide a way to number tasks in a project; the structure of the WBScode helps the reader identify the phase of the project in which the task occurs.




Task Constraints

Every task you enter into Project has some type of constraint applied to it. Aconstraint controls the start or finish date of a task and the degree to which that

task can be rescheduled. There are three categories of constraints:

Flexible constraints

Inflexible constraints Semi-flexible constraints




Adjusting Working Time for Individual Tasks

By default, your tasks are scheduled according to your Project Calendar. Butif a certain task needs to be done using a different calendar schedule, youcan assign a different calendar to the task.



Options



Help




Views




Using Split Views




Sorting Project Details

Tasks and resources appear in ID-number order in Project by default. However,you can change this by sorting them; sorting lets you rearrange the order in which

tasks and resources appear.




Grouping Project Details

Now we will concentrate on grouping. Grouping is a handy organizational tool,allowing you to focus on a variety of project angles. You can group tasks and

resources the same way.




Filtering Project Details

By filtering a list, you display only the records that meet your criteria, and hidethe records that do not. There are several ways to filter your lists.



Viewing Details



Using Zoom



Using View Bar



Building the Network

• AOA Network

• AON Network



A Sample Set of Project Activitiesand Precedences



Stage 1 of a Sample AONnetwork



Stage 2 of a Sample AONNetwork



A Completed Sample AONNetwork



Stage 1 of a Sample AOA

Network



Stage 2 of a Sample AOANetwork



A Completed Sample AOANetwork



A Completed Sample AOA NetworkShowing the Use of a Dummy Task



A Sample Problem for Finding theCritical Path and Critical Time

Activity Predecessor Duration

a -- 5 days

b -- 4

c a 3

d a 4

e a 6

f b, c 4

g d 5

h d, e 6

i f 6

j g, h 4



Stage 1 of a Sample Network



A Complete Network



Information Contents in an

AON Node



Forward Pass

Begin at starting event and work forward

Earliest Start Time Rule:

þ

If an activity has only a single immediate predecessor, itsES equals the EF of the predecessor þ If an activity has multiple immediate predecessors, its ES is

the maximum of all the EF values of its predecessors

ES = Max {EF of all immediate predecessors}



Forward Pass

Begin at starting event and work forward

Earliest Finish Time Rule:

þ

The earliest finish time (EF) of an activity is the sum of itsearliest start time (ES) and its activity time

EF = ES + Activity time



Backward Pass

Begin with the last event and work backwards

Latest Finish Time Rule:

þ

If an activity is an immediate predecessor for just a singleactivity, its LF equals the LS of the activity that immediatelyfollows it

þ If an activity is an immediate predecessor to more than oneactivity, its LF is the minimum of all LS values of all activitiesthat immediately follow it

LF = Min {LS of all immediate following activities}



Backward Pass

Begin with the last event and work backwards

Latest Start Time Rule:

þ

The latest start time (LS) of an activity is the difference of itslatest finish time (LF) and its activity time

LS = LF – Activity time



The Critical Path and Time for

Sample Project



Calculating Activity Slack

• Slack or FloatLST - EST = LFT - EFT = Slack



An MSP Version of

PERT/CPM Network



A Modified Version of MSPNetwork




Resources

Wh t i R ?



What is a Resource?

Costs in a Project are associated with resources.If you want to account for costs in your project, you have to create resourcesand assign them to the tasks.When you do, you can see the resulting costs in the Total Cost column of theGantt Chart spreadsheet.

You can create resources with no associated costs. You might do that so

you can track only that resource’s time. Some people use Project strictly asa scheduling tool, so watching the time people are spending on tasks is their only interest, not what the time is costing. If you don’t assign costs toresources, you get no cost or budget information back from Project.

Fixed costs aren’t assigned through resources because they don’t accumulatecosts by time of work or units used. A fixed cost is a set cost applied directly toindividual tasks.



Types of Resources

Project works with three types of resources:Work, Material, and Cost resources

Work resources are typically (but not always) people. They can’t bedepleted but can be reassigned. Their costs are associated with theamount of work time they put in, usually at an hourly rate or a cost per use.Work resources are assigned to tasks based on a Working Time calendar,where you specify their working and nonworking hours.

Material resources can have an hourly rate or a unit cost, and they alsohave an unlimited working time. This type of resource has no calendar, noovertime, and you make no settings for working and nonworking time.

Cost resources have a set cost associated with them. Calendars andunits of work or unit costs have nothing to do with the amount suchresources deduct from the bottom line of your project.




Setting Up People Resources

Once you have created a task list for your project, the next step is to create aresource list.

Work resources are the people and equipment that do the work of the project.

The easiest way to enter resources in a project is to use the Resource Sheet.



Resource Name: Type the name of the resource. For a person, you can type the

person’s name or you can type a job description, such as Product Analyst 1 or

Product Analyst 2.

Type: Use this column to specify whether you’re defining a human, material, or cost

resource. Project refers to human resources as Work.

Material Label: For material resources, specify the unit of measure. You can set up

any label that you want. For example, you can use minutes for long distance, feet

for lumber, or miles for gasoline.

Initials: Type initials for the resource, or accept the default that Project provides,

which is the first letter of the resource name. This designation appears on any view

to which you add the Initials field. Typically, a resource’s name appears, but you

can customize the view to display initials if you prefer.



Group: Assign resources to groups if they share some common characteristic,

such as job function. Then you can use this field as a filtering or sorting

mechanism and display information about the group (a particular job function) as

opposed to a specific resource. Just type a name to create a group.

Max. Units: Project expresses the amount of the work resource that you have

available for assignment as a percentage. For example, 100 percent equals one

unit, or the equivalent of one full-time resource; 50 percent equals one-half of a

unit, or one-half of a fulltime resource’s time; and 200 percent equals two full-timeresources.



Std. Rate: The standard rate is the rate that you charge for regular work for a

resource. Project calculates the default rate in hours. However, you can charge a

resource’s work in other time increments. (For work resources, you can use minutes,days, weeks, months, or years. For material resources, think of the charge as per

unit based on the Material Label.) To specify a time increment other than hours, type

a forward slash and then the first letter of the word representing the time increment.

For example, to charge a resource’s use in days, type /d after the rate that you

specify.Ovt. Rate: The overtime rate is the rate that you charge for overtime work for a work

resource. Again, Project calculates the default rate in hours, but you can change the

default unit the same way that you changed it for the standard rate.

Cost/Use: In the Cost/Use column supply a rate for costs that are charged for



Cost/Use: In the Cost/Use column, supply a rate for costs that are charged for

each use of the resource. Resource costs may be based on the Standard rate

(which is calculated by multiplying the number of hours times the cost per hour),

the Cost/Use rate (a fixed fee for use of the resource), or a combination of the

two. Project uses a combination of the Cost/Use field and the Std. Rate field when

calculating the cost of a task. If you rented a piece of equipment that costs youRs.250/hour plus a setup charge of Rs10,000, you would assign a Std. Rate of

Rs.250/hour and a Cost/Use of Rs.10,000.

Accrue At: This field specifies how and when Microsoft Project charges resource

costs to a task at the standard or overtime rates. The default option is Prorated,

but you also can select Start or End. The three are described as follows:

If you select Start and assign that resource to a task, Project calculates the

cost for a task as soon as the task begins.

If you select End and assign that resource to a task, Project calculates the

cost for the task when the task is completed.

If you select Prorated and assign that resource to a task, Project accrues

the cost of the task as you complete scheduled work.



Base Calendar : Base calendar identifies the calendar that Project should use

when scheduling the resource. The calendar identifies working and nonworking

time. Project assumes that each resource uses the Standard calendar, but as youread later in this chapter, you can create calendars for resource groups (perhaps

to handle shift work) or you can modify an individual resource’s calendar to reflect

vacation or other unavailable time (such as jury duty).

Code: You can use this field as a catchall field to assign any information that you

want to a resource, using an abbreviation of some sort. For example, suppose

that your company uses cost-center codes. You may want to supply the cost-

center code for the resource in the Code field. You can sort and filter information

by the abbreviations that you supply in the Code field.




Setting Up Equipment Resources

Equipment resources are also work resources, but they are different frompeople resources in the way they are used and scheduled. People generally

have a set number of working hours that they will contribute to a task eachday. But pieces of equipment don't really have a schedule: they can workaround the clock if it's needed.You don't have to track every piece of equipment that is used in the project,but you should keep track of equipment that accumulates cost or that isshared.

S tti U M t i l R




Setting Up Material Resources

Material resources are the goods needed by work resources to complete tasks.Tracking the use of material resources helps track the rate at which theresources are used, as well as their costs. This is especially applicable in

building and construction projects that use a lot of materials, such as cement,steel etc.

Setting Up Cost Resources




Setting Up Cost Resources

You can use a cost resource to represent a financial cost associated with atask in a project. Common types of cost resources might include categories of

expenses you’d want to track on a project for accounting purposes such astravel, entertainment, or training. Like material resources, cost resources do nowork and have no effect on the scheduling of a task. However, after you assigna cost resource to a task and specify the cost amount per task, you can thensee the cumulative costs for that type of cost resource, such as total travelcosts in a project.

R I f ti di l



Resource Information dialogbox

This section discusses the fields in the dialog box that

didn’t appear by default on the Entry table of theResource Sheet.

Adjusting Working Time for Individual Resources




Adjusting Working Time for Individual Resources

A resource calendar controls the working and nonworking times of a resource.Project uses resource calendars to determine when work for a specificresource can be scheduled. Resource calendars apply only to work resources

(people and equipment) and not to material or cost resources.

Setting Up Resource Availability to Apply at Different Times




Setting Up Resource Availability to Apply at Different Times

One of the values that Project stores for each work resource is the resource’s Max.Units value. This is the maximum capacity of a resource to accomplish tasks. Aresource’s working time settings (recorded in the individual resource calendars)

determine when work assigned to a resource can be scheduled. However, theresource’s capacity to work (measured in units and limited by the resource’s Max.Units value) determines the extent to which the resource can work within thosehours without becoming over allocated.

You can specify that different Max. Unitsvalues be applied at different time periods for any resource. Setting a resource’s availabilityover time enables you to control exactly whata resource’s Max. Units value is at any time.

You set resource availability over time in theResource Availability grid on the General tabof the Resource Information dialog box.

Booking



BookingtypeYou can specify a booking type for a resource assignment. Booking types are

most useful in the Enterprise environment, where you are utilizing theEnterprise Resource Pool.The Booking Type field offers you two choices: Committed and Proposed.When you commit a resource, you are officially assigning the resource to theproject. When you propose to use a resource, you are indicating that theresource is not yet officially assigned to the project, which essentially leaves theresource’s calendar untouched by the proposed assignment to your project. Another project manager could commit the resource to a different project for the same time frame, and Microsoft Project will not identify the resource asbeing overallocated. Project does not consider proposed bookings whencalculating resource allocation.The Booking type that you choose for a resource applies to all tasks inyour project to which you assign the resource.

G i



GenericResourceGeneric Resources — resources (as defined by you) that aren’t specificpeople, equipment, or materials, but rather descriptions of the skills that youneed for a task when you don’t know what specific resources are available.

To mark a resource as generic, place a check mark in the Generic box on theGeneral tab of the Resource Information dialog box. Your company may haveset up custom fields in Project that apply to your generic resource. To assignthe appropriate custom fields, click the Custom Fields tab and assign any

appropriate values to your genericresource.

Budget



BudgetResourceBudget resources give you the opportunity to specify how work or costs will beallocated during the project. Suppose, for example, that you want to budget for

the cost of a storage unit required during the life of your project. You wouldcreate a resource for the storage unit, setting its type as Cost, and then checkthe Budget check box on the General tab of the Resource Information dialogbox to make it a budget resource.

Project doesn’t allow you to enter any cost information for a budget resource onthe Resource Sheet. To assign a value to the budget resource, you first assignit to the project summary task—and Project won’t let you assign a value as youassign the budget resource. Then, you supply a value by adding the BudgetCost field to the table in the Task Usage view or the Resource Usage view.

Budget



You also can set up a work budget resource that you can use to budget for thenumber of hours of work you intend to perform for the entire project. You then

assign the work budget resource to the project summary task. To record thenumber of hours of work you want to budget for the entire project, add theBudget Work field to the Task Usage view or the Resource Usage view andenter your budget value. As you track the work for your project’s tasks, youcan compare the work performed with the budgeted work.

…… BudgetResource

Resources that work in groups



Resources that work in groups

Although you can't assign a group of resources to a single task, it is helpful toorganize resources into logical groups for organizational purposes. Grouping

allows you to view how resources are related, similar to outlining the task list.

Assigning Resources to Tasks




Assigning Resources to Tasks

Matching up tasks and resources to do work is called an assignment. Assignments enable your project to move forward and make progress.Technically, you could complete a project without any resources, but resource

assignments help you find out valuable information:

Assigning Equipment Resources to a Task




Assigning Equipment Resources to a Task

Assigning Material Resources to Tasks




Assigning Material Resources to Tasks

Assigning Cost Resources to Tasks




Assigning Cost Resources to Tasks

Assigning a fixed cost to a task




Assigning a fixed cost to a task

Some tasks are fixed-cost tasks, that is, you know that the cost of a particular taskstays the same regardless of the duration of the task or the work performed by

any resources on the task.To assign a fixed cost to a task, use the Gantt Chart view and apply the Costtable. Follow these steps:1. Use the View bar or the View menu to switch to the Gantt Chart view.2. Choose View Table: Entry Cost to switch to the Cost table view of the Gantt

Chart,

3. Select the task to which you want to assign a fixed cost.4. Type the cost for that task in the Fixed Cost column and press Enter.

You can control the way that Project accrues the fixed cost for a task from theFixed Cost Accrual column. Your choices are Start, Prorated, and End. You can assign more than one fixed cost as well as variable costs to a task.

Assigning a fixed resource cost to a task



Assigning a fixed resource cost to a task

Set up the resource in the Resource Sheet view. If the resource has somesort of “per unit” cost (an hourly or daily rate), assign that rate in the Std.Rate field. Otherwise, assign a standard rate of Rs.0.

Supply the fixed-cost amount in the Cost/Use field.

Assigning a budget resource



Assigning a budget resource

To assign a budget resource to your project, you must first display the projectsummary task. Choose Tools Options and click the View tab. Place a check

in the Show Project Summary Task check box. When you click OK, the firsttask in your project bears the filename of the project.Click the project summary task and then choose Tools Assign Resources to

open the Assign Resources dialog box. Click the budget resource and click Assign. Project places a check in the leftmost column beside the resource toindicate that the resource is assigned to the selected task. You cannot assignany value to the budget resource at this point, so click Close.

To assign a value to a budget resource, switch to the Task Usage or theResource Usage view; in, I’m using the Task Usage view. To add the budgetresource value on a specific day, add the Budget Cost or Budget Work fieldsto the Details section of the view and enter the budget value. To add thebudget resource value to the project, regardless of the timeframe, add theBudget Cost and Budget Work fields to the table portion of the view and enter

the budget value.

Getting help while selecting resources to assign



g p g g

You may have noticed a plus sign (+) next to Resource

List options at the top. If you click the plus sign, the boxexpands, to provide you with ways to make selectingresources easier.

Removing or replacing a resource assignment



Removing or replacing a resource assignment

To remove a resource assignment, select the task from which you want to

remove the resource assignment using the Gantt Chart view. Then click the Assign Resources button or choose

Tools Assign Resources

to display the Assign Resources dialog box. Highlight the resourcethat you want to remove from the task. You should see a check mark next tothe resource in the leftmost columnof the dialog box. Click Remove.

Effort Driven Scheduling




Effort Driven Scheduling

The Scheduling Formula

Work = Duration xUnits

40 hours task duration x 100% resource units = 40 hours of work

20 hours task duration x 200% resource units = 40 hours of work

You can turn off effort-driven scheduling for every new task that you create. SelectTools >> Options from the menu, click the Schedule tab, and uncheck the Newtasks are effort driven checkbox.

Wh D i T k Ti i



What Drives Task Timing

The timing of tasks is at the heart of all projects.

When you perform a task, the time it takes to complete it might be a settime, or the task might not finish until all the work is done.

Task types

Task types define the relationship that balances a task’s duration, the workrequired to complete the task, and resource availability.

Fixed UnitsFixed Duration

Fixed Work

Fixed Units: This is the default task type With this task type when you assign



Fixed Units: This is the default task type. With this task type, when you assignresources to a task with a certain number of units (hours of work expressed as apercentage of the working day), the resources’ assignments don’t change even if you change the duration of the task and the work amount.

Fixed Duration: This task type takes a set amount of time to complete,no matter how many resources you add to the mix.

Fixed Work: The number of resource hours assigned to the task determinesits length. If you set the duration of a Fixed Work task at 40 hours, for example, and you assign two resources to work 20 hours each(simultaneously) at units of 100 percent, the task will be completed in 20

hours. If you take away one of those resources, the single resource must putin 40 hours at units of 100 percent to complete the task.

Task Types




Assigning Additional Resources to a Task




There are two ways to assign multiple resources to a task:

Assign multiple resources when the assignment is created.

Assign additional resources after the assignment is created.

Changing Task Types




Defining task types changes how tasks are scheduled. For any task,setting the task type determines which part of the scheduling equationMicrosoft Project uses to schedule a task. Once a resource assignment is

created, tasks are scheduled using this formula:

Duration = Work / Units

Work = Duration x Units "Effort driven" checkbox

This option tells MicrosoftProject to keep the totaltask work at its currentvalue. The duration of atask shortens or lengthensas resources are added or

removed from a task, whilethe amount of effortnecessary to complete atask remains unchanged.




Advance Resource Schedule

Entering Multiple Pay Rates for a Resource




Some work resources might perform different tasks withdifferent pay rates.

Setting Up Pay Rates to Apply at Different Times




Resources can have both standard and overtime pay rates. By default, Projectuses these rates for the duration of the project. However, you can change aresource’s pay rates to be effective as of the date you choose.

Delaying the Start of Assignments




If more than one resource is assigned to a task, you might not want all of theresources to start working on the task at the same time. You can delay the startof work for one or more resources assigned to a task.

Applying Contours to Assignments




In the Resource Usage and Task Usage views, you can see exactly how long eachresource is scheduled to work on each task. In addition to viewing assignmentdetails, you can change the amount of time a resource works on a task in anygiven time period. There are two ways to do this:

• Apply a predefined work contour to an assignment.• Edit the assignment details directly.



Applying Different Cost Rates to Assignments




You can set as many as five pay rates per resource, which allows you to applydifferent pay rates to different assignments for a resource. Project initially usesrate table A by default, but you can specify that another rate table should be

used.

Entering Material Resource Consumption Rates




Material Resource Consumption

• fixed consumption rate•

variable consumption rate

A fixed consumption rate means that, regardless of the duration of the task towhich the material resource is assigned, an absolute quantity of the resource willbe used. For example, pouring concrete for a house foundation requires a fixed

amount of concrete no matter how long it takes to pour it.

A variable consumption rate means that the quantity of the material resourceconsumed depends on the duration of the task. When shooting film, for example,you can shoot more film in four hours than in two, and you can determine an hourlyrate at which you shoot (or consume) film. After you enter a variable consumptionrate for a material resource’s assignment, Project calculates the total quantity of thematerial resource consumed based on the task’s duration. The advantage of usinga variable rate of consumption is that the rate is tied to the task’s duration. If theduration changes, the calculated quantity and cost of the material resource willchange as well.



PROJECT UNCERTAINTY AND RISK MANAGEMENT



The Statistical Distribution of all



The Statistical Distribution of allPossible Times for an Activity

Activity Expected Time and



Activity Expected Time andVariance

2

2

E

6

)(Var

6

)(

6

)4(T

−

==

−=

++=

ab

ab

bma

σ

σ

95 Percent Level



95 Percent Level

• Task will be a or lower 5 percent of thetime

• Task will be b or greater 5 percent of

the time

3.3

)( ab −

=σ

90 Percent Level



90 Percent Level

• Task will be a or lower 10 percent of thetime

• Task will be b or greater 10 percent of

the time

6.2

)( ab −

=σ

95 Percent Level (Alternative



95 Percent Level (AlternativeInterpretation)

• Task will be between a and b 95

percent of the time

90 Percent Level (Alternative



90 Percent Level (AlternativeInterpretation)

• Task will be between a and b 90percent of the time

29.3

)( ab −=σ

An AON Network



An AON Network

An MSP Version of a Sample



An MSP Version of a SampleProblem Network

A Pert/CPM Network for the



A Pert/CPM Network for theDay Care Project

An MSP Calendar for the Day Care



yProject, 4/16/00 to 5/27/00

The Probability of Completing



The Probability of Completingthe Project on Time

2

)(

µ σ

µ −=

D

Z

=NORMDIST(D, , ,TRUE)

The Statistical Distribution of Completion



The Statistical Distribution of CompletionTimes of the Path a-b-d-g-h

Selecting Risk and Finding D



Selecting Risk and Finding D

2

µ σ µ Z D +=

NORMINV(probability, , ,TRU

E)

AON Example



p

Activity DescriptionImmediate

Predecessors A Build internal components —

B Modify roof and floor —C Construct collection stack A

D Pour concrete and install frame A, B

E Build high-temperature burner C

F Install pollution control system C

G Install air pollution device D, E

H Inspect and test F, G

Project Schedule



Activity Description Time (weeks)

A Build internal components 2

B Modify roof and floor 3

C Construct collection stack 2D Pour concrete and install frame 4

E Build high-temperature burner 4

F Install pollution control system 3

G Install air pollution device 5

H Inspect and test 2Total Time (weeks) 25

Project Schedule

AON Network



AON Network

G

E

F

H

CA

Start

DB

AOA Network



H

(Inspect/ Test)7

AOA Network

6

F ( I n s t a l l

C o n t r o l s )

E

( B u i l d

B u r

n e r )

G ( I n s t a l l

P o l l u

t i o n

D e v i c

e )

5D

(Pour Concrete/Install Frame)

4C

(ConstructStack)

1

3

2

B ( M o d i f y

R o o f / F l o o r )

A

( B u i l d

I n t e r n a l

C o m p o

n e n t s )

Determining the Project Schedule



Determining the Project Schedule

Perform a Critical Path Analysis

A

Activity Nameor Symbol

EarliestStart

ESEarliestFinishEF

LatestStart

LS LatestFinish

LF

Activity Duration

2

LS/LF and ES/EF Times



LS/LF and ES/EF Times

E

4

F

3

G

5

H

2

4 8 13 15

4

8 13

7

13 15

10 13

8 13

4 8

D

4

3 7

C

2

2 4

B

3

0 3

Start

0

0

0

A

2

20

42

84

20

41

00

Computing Slack Time



Computing Slack Time

Earliest Earliest Latest Latest OnStart Finish Start Finish Slack Critical

Activity ES EF LS LF LS – ES Path

A 0 2 0 2 0 YesB 0 3 1 4 1 NoC 2 4 2 4 0 YesD 3 7 4 8 1 NoE 4 8 4 8 0 YesF 4 7 10 13 6 No

G 8 13 8 13 0 YesH 13 15 13 15 0 Yes

Critical Path



Critical Path

E

4

F

3

G

5

H

2

4 8 13 15

4

8 13

7

13 15

10 13

8 13

4 8

D

4

3 7

C

2

2 4

B

3

0 3

Start

0

0

0

A

2

20

42

84

20

41

00

ES – EF Gantt Chart



ES EF Gantt Chart

A Build internalcomponents

B Modify roof andfloor

C Construct collectionstack

D Pour concrete andinstall frame

E Build high-temperature burner

F Install pollutioncontrol system

G Install air pollutiondevice

H Inspect and test

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

LS – LF Gantt Chart



LS LF Gantt Chart

A Build internalcomponents

B Modify roof andfloor

C Construct collectionstack

D Pour concrete andinstall frame

E Build high-temperature burner

F Install pollution

control system

G Install air pollutiondevice

H Inspect and test

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

Variability in Activity Times



þ CPM assumes we know a fixed timeestimate for each activity and there is

no variability in activity timesþ PERT uses a probability distribution for activity times to allow for variability





þ Three time estimates are requiredþ Optimistic time (a) – if everything goes

according to plan

þ Pessimistic time (b) – assuming veryunfavorable conditions

þ Most likely time (m) – most realistic

estimate





Estimate follows beta distribution


Expected time:

Variance of times:t = (a + 4m + b)/6

v = [(b – a)/6]2




Estimate follows beta distribution


Expected time:

Variance of times:t = (a + 4m + b)/6

v = [(b − a)/6]2Probability of 1in 100 of > boccurring

Probability of 1in 100 of < a occurring

P r o b a b i l i t y

OptimisticTime (a)

Most LikelyTime (m)

Pessimistic Time(b)

ActivityTime

Figure 3.12

Computing Variance



Computing Variance

Most ExpectedOptimistic Likely Pessimistic Time Variance

Activity a m b t = (a + 4m + b)/6 [(b – a)/6]2

A 1 2 3 2 .11B 2 3 4 3 .11C 1 2 3 2 .11D 2 4 6 4 .44E 1 4 7 4 1.00F 1 2 9 3 1.78

G 3 4 11 5 1.78H 1 2 3 2 .11

Probability of Project



y jCompletion

Project variance is computed bysumming the variances of criticalactivities

σ2 = Προϕεχτ ϖαριανχε

= ∑(ϖαριανχεσ οφαχτιϖιτιεσ

ον χριτιχαλ πατη)

p




y jCompletion

Project variance is computed bysumming the variances of criticalactivitiesProject variance

σ2 = .11 + .11 + 1.00 + 1.78 + .11 = 3.11

Προϕεχτ στανδαρδ δεϖιατιον

σπ = Προϕεχτ ϖαριανχε= 3.11 = 1.76 ωεεκσ

p




y jCompletion

PERT makes two more assumptions:

þ Total project completion times follow anormal probability distributionþ Activity times are statistically independent




Completion

Standard deviation = 1.76 weeks

15 Weeks

(Expected Completion Time)




Completion

What is the probability this project can becompleted on or before the 16 weekdeadline?

Z = –

/σπ

= (16 ωκσ 15 ωκσ)/1.76

= 0.57

due expected datedate of completion

Where Z is the number of standarddeviations the due date or target date lies

from the mean or expected date




y jCompletion

What is the probability this project can becompleted on or before the 16 weekdeadline?

Z = −

/σπ

= (16 ωκσ 15 ωκσ)/1.76

= 0.57

due expected datedate of completion

Where Z is the number of standarddeviations the due date or target date lies

from the mean or expected date

.00 .01 .07 .08

.1 .50000 .50399 .52790 .53188

.2 .53983 .54380 .56749 .57142

.5 .69146 .69497 .71566 .71904

.6 .72575 .72907 .74857 .75175

From Appendix I




Completion

Time

Probability(T ≤ 16 weeks)

is 71.57%

0.57 Standard deviations

15 16Weeks Weeks

Determining Project



g jCompletion Time

Probability of 0.01

Z

Figure 3.15

From Appendix I

Probability of 0.99

2.33 Standarddeviations

0 2.33

Variability of Completion Time



Variability of Completion Time

for Noncritical Pathsþ Variability of times for activities on

noncritical paths must be considered

when finding the probability of finishing in a specified timeþ Variation in noncritical activity may

cause change in critical path

What Project Management



Has Provided So Far

þ The project’s expected completion time is15 weeks

þ There is a 71.57% chance the equipment

will be in place by the 16 week deadlineþ Five activities (A, C, E, G, and H) are on thecritical path

þ Three activities (B, D, F) are not on thecritical path and have slack time

þ A detailed schedule is available



Thank You

MS Projects Day 3 Final

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