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PERT REVIEW (last part of Ch 7)

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Title: PERT REVIEW (last part of Ch 7)


1
TODAY
  • PERT REVIEW (last part of Ch 7)
  • CAPM Exam Details
  • Time and Cost Estimation

2
PERT (Program Evaluation and Review Technique)
  • Not supported by MS Project
  • Gives you probabilities of completion of a
    project by a certain time
  • Calculates a standard normal random variate and
    uses a probability table to find its probability

3
PERT INPUTS
  • A most optimistic time
  • M most likely time
  • B most pessimistic time

4
PERT formulas
  • Task mean (A 4M B)/6
  • Task Std. Dev. (B-A)/6
  • Project mean sum of all the task means of tasks
    on the critical path
  • Project std. Dev sum of all the task standard
    deviations of tasks on the critical path

5
Beta Distribution
a m
b
6
PERT Homework Assignment
7
The CAPM
- The cost of joining PMI student member is
32/year (32 to renew). Therefore, joining PMI
first (using the on-line registration) will
reduce your examination costs and you will
receive all of the other benefits and discounts
available to members. - To apply for the CAPM,
you need to have A secondary degree (high school
diploma or the global equivalent) AND at least
1,500 hours of project experience OR 23 hours of
project management education by the time you sit
for the exam. - To apply for the PMP, you need to
have A four-year degree (bachelors degree or
the global equivalent) AND at least three years
of project management experience, with 4,500
hours leading and directing projects and 35 hours
of project management education. - The CAPM exam
is focused on the PMBOK Guide. It consists of 150
questions made up of 135 'scored' questions and
15 pre-test questions (3-hour exam). The pass
mark for CAPM is at 65. There are no minimum
requirements in each section. The CAPM
certification lasts for 5 years. At the end of
this period you either need to re-sit the
examination or more likely take your PMP
examination. - The structure of the CAPM exam is
  • The CAPM Certification lasts 5 years
  • Then you must re-take the CAPM exam or take the
    PMP exam
  • Joining PMI as a student costs 32/yr
  • Joining gives you free access to PMBOK and other
    ebooks
  • Joining reduces the cost to sit for the exam

8
The CAPM Exam
  • 150 Questions
  • 15 pretest questions
  • 135 actual exam questions over PMBOK
  • 3 hour exam
  • The pass threshold is 65

9
CAPM Exam Structure
10
Estimating Task Durations and Costs
11
Estimation An ART
  • That made McDonnell (of McDonnell/Douglas
    Aircraft) wealthy
  • Accurate intelligence information is a help

12
Three types of cost estimates
  • Five-ten year-out planning
  • Ballpark estimatesbetter to over estimate
  • Used to make decisions about which projects will
    be funded when
  • Two-year-out planning
  • More refined estimates that consider current
    costs
  • Immediate execution estimates
  • Used to drive execution

13
INPUTS 1. Activity list 2. Constraints 3.
Assumptions 4. Resource requirements 5.
Resource capabilities 6. Historical information
TOOLS 1. Expert judgment 2. Historical
data 3. Analogous estimating 4. Simulation
OUTPUTS 1. Activity duration estimates 2.
Basis of estimates 3. Activity list updates
14
The Cost estimation StorySteve McConnell
  • You cant tell exactly what its going to cost
    until you know exactly what IT is.
  • (Which is why we spent so much time talking about
    thorough product conceptualization and
    definition)

15
The WBS as price estimating tool
  • Provides the basis for effective and open
    communication between functional management and
    program/project management
  • After pricing is complete the WBS forms the basis
    of a communications tool by documenting the
    performance agreed on in the pricing effort.

16
Differentiate Estimates from Targets and
Commitments
  • We will have it done in three months
  • Why three months???
  • Because that is when the trade show happens

17
Is it better to overestimate or under estimate
Effect Cost Schedule
Underestimation
Overestimation
100
lt100
gt100
Target as a Percentage of Nominal Estimate
18
A Rule of Thumb
  • The time to design, document and code a module
  • equals the time to debug it (TEST IT)
  • At least 45 of the total time devoted to testing
  • According to Gildersleeve

19
Cone of Uncertainty
20
The Standish Groups Project Outcomes
21
Estimating Rules (Rakos)
  • Never use inexperienced persons to estimate
  • Get group estimates if possible
  • Never force an estimate on a programmer
  • Never take an average of different estimates
  • Granularize down to FOUR or less weeks, roughly
  • Always add for contingency
  • Always quote a range when giving estimates

22
Rakos Conclusions to Estimating
  • Our weakest talent
  • Estimating is iterative
  • Estimating is still an art

23
Review Project Time Management Processes
  • Project time management involves the processes
    required to ensure timely completion of a
    project. Processes include
  • Define activities
  • Sequence activities
  • Estimate Activity resources
  • Estimate Activity durations
  • Develop Schedule
  • Control Schedule
  • Which of these gets performed in the Planning and
    Budgeting Stage??

24
A Typical Task Duration Process
  • Assign the task to a project player
  • Ask the player how long it will take him or her
    to complete the task (This gives the player
    ownership in the planning)
  • Player provides their best estimate
  • The player understands that they will be required
    to complete the task within their estimatetheir
    feet will be held to the fire

25
Time Estimation Goldratt
  • Claims team players add safety to their estimates
  • What is safety??
  • Can determine how much by asking the question,
    How sure are you that you will finish your task
    in the time you allotted?

26
Time Estimation--programmers
  • Naïve programmers have a horrible reputation for
    underestimating task durations and costs

27
Time Estimationmaking time for creativity SLACK
  • Keep in mind that customers unintentionally put
    projects under extraordinary schedule
    pressuremore for less
  • A consideration in schedule development is to
    take the tasks requiring creativity and place
    them on ____?!?

28
Too little time syndrome
29
Needed A Rule-based Expert System for adjusting
individual task durations
  • IF ESTIMATER IS SEASONED (EXPERIENCED) AND IF THE
    WORK PACKAGE REQUIRES CREATIVITY ON THE PART OF
    THE ESTIMATOR, THEN LEAVE ESTIMATE AS IS.
  • IF ESTIMATER IS NOT SEASONED AND ESTIMATE APPEARS
    TO BE OPTIMISTIC, THEN INCREASE ESTIMATE BY 30.

30
ANOTHER AI RULE
  • IF ESTIMATOR IS SEASONED AND ESTIMATOR ASSERTS
    90 OR ABOVE CONFIDENCE HE WILL COMPLETE WORK
    WITHIN HIS ESTIMATE AND IF WORK PACKAGE DOES NOT
    REQUIRE SIGNIFICANT CREATIVITY, REDUCE ESTIMATE
    BY 40 -- 50

31
Time Estimation
  • What are the three approaches to time
    estimation??
  • Expert judgment
  • History database
  • Computer model or formula

32
Project Cost Management Processes
  • Plan Cost Management
  • Estimate Costs developing an estimate of the
    costs and resources needed to complete a project
  • Determine Budget allocating the overall cost
    estimate to individual work items to establish a
    baseline for measuring performance
  • Control Costs controlling changes to the project
    budget

33
Cost Estimating
  • We need to speak the language and understand the
    terminology
  • ROI, IRR, NPV, Sunk costs
  • Tangible and intangible costs
  • Direct and indirect costs
  • Learning curve theory
  • Reserves ( included in a cost estimate to
    mitigate cost risk also called contingency
    reserves)

34
Cost Estimating
  • An important output of project cost management is
    a cost estimate
  • There are several types of cost estimates and
    tools and techniques to help create them
  • It is also important to develop a cost management
    plan that describes how cost variances will be
    managed on the project

35
Proposal Pricing Strategies--Kerzner
  • Type I Acquisition One of a kind project with
    little or no follow-on opportunity
  • win the project, perform well and make a profit
  • Type II Acquisition New Program with potential
    for large follow-on business or representing a
    desired surge into a new market
  • win the project, perform well and gain a foothold
    in a new market segment, usually at a loss

36
Table 6-2. Three Types of Cost Estimates
37
Overhead Rates
  • Program/project costs involve both direct labor
    and indirect (OVERHEAD) costs
  • Each team member should understand overhead rates
  • If overhead rates are more than 50 of direct
    regular time and not chargeable to overtime, then
    overtime at 150 regular time may be cheaper
  • Overhead rates in manufacturing can be 300-450

38
Elements of Overhead Rates (Indirect Costs up
to 90 of total costs)
  • Building maintenance
  • Building rent
  • Cafeteria
  • Clerical
  • Consulting
  • Corporate Salaries
  • Depreciation of equip.
  • Executive Salaries
  • Group Health insurance
  • Holidays
  • Moving/storage exp.
  • Personnel recruitment
  • Retirement plans
  • Sick leave
  • Telephone/Utilities
  • Vacation

39
Why are Overhead Rates of Interest to Project
Management???
  • These rates must be included in any project cost
    calculation!!!
  • The contractor is going to pay both your direct
    and your indirect overhead costs if yours is the
    winning bid
  • Where do the costs associated with bidding and
    proposing go? Does anybody pay for them or are
    they just a SUNK cost???

40
Estimation in GeneralCOST or TIME
  • History data base
  • Expert judgement
  • a model like COCOMO

41
Cost Estimation Tools and Techniques
  • 4 basic tools and techniques for cost estimates
  • Analogous or top-down use the actual cost of a
    previous, similar project as the basis for the
    new estimate
  • Bottom-up estimate individual work items and sum
    them to get a total estimate, as is done with the
    WBS
  • Parametric use project characteristics in a
    mathematical model to estimate costs
  • Computerized tools use spreadsheets, project
    management software, or other software to help
    estimate costs

42
Constructive Cost Model (COCOMO)
  • Barry Boehm helped develop the COCOMO models for
    estimating software development costs
  • Parameters include source lines of code or
    function points
  • COCOMO II is a computerized model available on
    the web
  • Boehm suggests that only parametric models do not
    suffer from the limits of human decision-making

43
Factors Impacting COCOMO Cost
44
Cost Realism
  • A term widely used in the IT project management
    real
  • Not an exact prediction
  • Cost realism is about the system of logic, the
    assumptions about the future, and the
    reasonableness of the historical basis
  • The more preliminary and less studied the
    estimate, the more It should over-state the
    actual cost

45
Lets REVIEW What are the Major Cost Components?
  • Salary structure
  • Overhead structure (Indirect labor costs)
  • 50 at TTU
  • Direct Labor hours required times average hourly
    rate
  • Cost of materials and support

46
Cost of Materials??
  • Required Software
  • Diet coke, pizza

47
Stop herewill not test you on anything else
48
STOP!!!
  • Stop
  • Stop
  • Stop
  • Stop
  • Stop
  • Stops

49
Lefkons Methodology
1.  Divide the software project into as many
individual steps/tasks/modules as
possible. 2. Predict the level of effort required
to complete each task and multiply that
prediction by 2. 3.  Add up the numbers and
multiply by 2.0 again to account for testing and
debugging. 4.  Take the total and multiply by
1.25 to account for meetings, administration, and
paperwork. 5. Multiply this level of effort by
your companys magic number for labor costs.  
50
Lefkons Methodology
  • 6. Present this to management as a range. Take
    the cost as predicted above and present the range
    as 10 percent and 25 percent.
  • 7.  Stand your ground and remind management that
    you did not arbitrarily come up with these
    numbers and they cannot be adjusted arbitrarily.
    You may have to suggest reducing scope and cost
    if management does not agree with your estimate.
  • 8. Revise your project budget as you undertake
    and complete the project.

51
Typical Problems with IT Cost Estimates
  • Developing an estimate for a large software
    project is a complex task requiring a significant
    amount of effort. Remember that estimates are
    done at various stages of the project
  • Many people doing estimates have little
    experience doing them. Try to provide training
    and mentoring.
  • IT People have a bias toward underestimation.
    Review estimates and ask important questions to
    make sure estimates are not biased
  • Management wants a number for a bid, not a real
    estimate. Project managers must negotiate with
    project sponsors to create realistic cost
    estimates

52
Table 6-3. Business Systems Replacement Project
Cost Estimate Overview
53
Table 6-4. Business Systems Replacement Project
Cash Flow Analysis
54
Cost Budgeting
  • Cost budget involves allocating the project cost
    estimate to individual work items and providing a
    cost baseline
  • For example, in the Business Systems Replacement
    project, there was a total purchased costs
    estimate for FY97 of 600,000 and another 1.2
    million for Information Services and Technology
  • These amounts were allocated to appropriate
    budgets as shown in Table 6-5

55
Table 6-5. Business Systems Replacement Project
Budget Estimates for FY97 and Explanations
56
Designing the Baseline
  • One of the most crucial inputs to the pricing
    decision
  • Baseline design should be started early so its
    cost estimates can be included in the proposal
  • Effective pricing should begin a long time before
    proposal development
  • Gives management an opportunity to terminate a
    bid initiative before too many resources get
    committed to proposal development, presentations,
    negotiations, etc..

57
Pricing Process
  • This activity schedules the development of the
    work breakdown structure and provides management
    with two of the three operational tools necessary
    for the control of a system or project
  • The third tool is the WBS

58
The WBS as price estimating tool
  • Provides the basis for effective and open
    communication between functional management and
    program/project management
  • After pricing is complete the WBS forms the basis
    of a communications tool by documenting the
    performance agreed on in the pricing effort.

59
Organizational Input Requirements
  • After the WBS and activity schedules are
    established, an organizational meeting is called.
  • The WBS is described in depth
  • Responsibilities are clarified
  • Costing information is solicited and collected
    from the responsible parties
  • A short time fuse is usually involved in
    estimating/pricing which makes it all the more
    risky
  • RFPs sometimes require a response within 30 days
    of their submittal

60
Labor Distributions
  • Functional units supply their input in the form
    of man-hours
  • See Figure 14-2
  • Man-hours submitted are often over-estimated
  • Man-hours are converted to dollars by multiplying
    by the labor rates
  • Rates are only averages
  • Base rates are then escalated as a factor,
    based on past experience

61
Labor Distributions--Conflict Resolution
  • The reduction of man-hours is often the source of
    heated discussions between project and functional
    management
  • Most common solution rests with the project or
    program manager
  • This becomes the usual turf-fight
  • How would you resolve all such conflicts???

62
A Proposal Manager
  • Integrates the activities of the program and
    functional managers
  • Insures that a robust proposal gets submitted to
    the REQUESTER on time

63
Overhead Rates
  • Program/project costs involve both direct labor
    and indirect (OVERHEAD) costs
  • Each team member should understand overhead rates
  • If overhead rates are more than 50 of direct
    regular time and not chargeable to overtime, then
    overtime at 150 regular time may be cheaper
  • Overhead rates in manufacturing can be 300-450

64
Elements of Overhead Rates (Indirect Costs)
  • Building maintenance
  • Building rent
  • Cafeteria
  • Clerical
  • Consulting
  • Corporate Salaries
  • Depreciation of equip.
  • Executive Salaries
  • Group insurance
  • Holidays
  • Moving/storage exp.
  • Personnel recruitment
  • Retirement plans
  • Sick leave
  • Telephone/Utilities
  • Vacation

65
Why are Overhead Rates of Interest to Project
Management???
  • These rates must be included in any project cost
    calculation!!!
  • The contractor is going to pay both your direct
    and your indirect overhead costs if yours is the
    winning bid
  • Where do the costs associated with bidding and
    proposing go? Does anybody pay for them or are
    they just a SUNK cost???

66
Lets REVIEW What are the Major Cost Components?
  • Salary structure
  • Overhead structure
  • Labor hours required
  • Cost of materials and support

67
Cost of Materials??
  • Required Software
  • Diet coke, pizza

68
Materials Support Costs
  • Are submitted by month for each month of the
    project
  • An escalation factor for material costs must be
    applied

69
Pricing out the WorkSTEPS (from Kerzner, p. 738)
  • Provide a complete definition of the work
    requirements
  • Establish a logic network with checkpoints
  • Develop the work breakdown structure
  • Price out the WBS

70
Pricing out the Work--STEPS, Contd
  • Review WBS costs with each functional manager
  • Decide on the basic course of action
  • Establish reasonable costs for each WBS element
  • Review the base case costs with upper-level
    management

71
Pricing out the Work--STEPS, Contd
  • Negotiate with functional managers for qualified
    personnel
  • Develop the linear responsibility chart
  • Develop the final detailed and PERT/CPM schedules
  • Establish pricing cost summary reports
  • Document the result in a project plan

72
Smoothing out Department Man-hours
  • Ramp-up at project initiation and Ramp-down at
    project completion cause step functions in
    manpower requirements, as shown in Figure 14-8
  • Functional managers attempt to SMOOTH this out
  • QUESTION?? Does the department have sufficient
    resources to fulfill the requirements?

73
Smoothing out Department Man-hours
  • ANOTHER QUESTION?? Can the departments ramp-up
    fast enough?

74
The Pricing Review Procedure
  • Based on Kerzners work
  • Remember only 30 days to get the proposal out and
    this is one of 13 steps
  • Many contractors require the actual team members
    to be identified in the proposal
  • What solution comes to mind?

75
Systems Pricing
  • The project pricing model (also called the
    strategic planning model) acts as a management
    information system
  • Also provides management with an invaluable tool
    for performing perturbation analysis on the base
    case costs

76
Developing the Supporting/Backup Costs
  • Some proposals require backup support
  • When required backup support must be included in
    the pricing
  • An issue is the type of contract

77
Types of contracts
  • Fixed-price (developer assumes all of the risk)
  • Cost-plus (contractor pays for every hour
    invested and thus assumes all the risk)
  • An infinite array in between these

78
The Low-Bidder Dilemma
  • The price of your contract will definitely affect
    the viability of your proposal
  • A low price on cost-plus type proposals is
    suspect
  • A low price on fixed-price contracts may be
    perceived as impossible and undoable, or if
    accepted will lead to a disaster

79
The Price on the Proposal is always relative to
  • the competitive prices
  • the customer budget
  • the bidders cost estimate
  • IN ANY CASE, LOW PRICING WITHOUT MARKET
    INFORMATION IS MEANINGLESS

80
If its a new market for the Developer
  • Cost sharing may be an effective strategy
  • Bidding below your actual costs is commonplace
  • Contractors objectives might include system life
    cycle cost or unit production cost

81
The Bottom Line on Price
  • THE LOWEST BIDDER IS NOT NECESSARILY THE
    AUTOMATIC WINNER
  • Makes project a risky image regarding cost,
    performance or schedule
  • The ability to perform under contract is a
    definite consideration
  • A compliant, technically and managerially sound
    proposal based on past experience, with
    realistic, well-documented cost figures, is often
    chosen over the lowest bidder

82
Special Problems
  • Pricing must include an understanding of cost
    control--how costs are billed back to the project
  • There are three situations
  • Work is priced out at the department average, and
    all work performed is charged to the project at
    the department average, regardless of who
    performed the work
  • Work is priced out at the dept.. average, but all
    work performed is billed back to the project at
    the actual salary of the employees who performed
    the work
  • Work is priced out at the actual salary of those
    employees who will perform the work, and the cost
    is billed back the same way.
  • This is the ideal situation

83
This is as far as we will go with these
slidesignore the remainder
84
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85
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86
Estimating Pitfalls
  • The buy-in decision is the most serious pitfall
    because it means that the project will be
    under-funded
  • If the customer initially defines the
    requirements and you (the developer) further
    refine them and the customer doesnt understand
    what youve done, whose fault is it?

87
Estimating High-Risk Projects
  • Validity of historical estimates determine the
    difference between high-risk and low-risk
    projects
  • Estimating high-risk projects is commonly done by
    means of the rolling wave or moving window
    approach
  • For a 12-month project the first six months are
    estimated to level 5, while the last six months
    are estimated to level two only.
  • As the project proceeds more and more of the last
    six months is estimated to level 5
  • See Figure 14-13, Kerzner

88
Project Risks
  • RISKS--Factors that increase the probability that
    the projects goals of time, cost and performance
    will not be met
  • See Figures 14-14, 14-15 and Table 14-13
    (Especially useful)

89
Common Risks include
  • Poorly defined requirements
  • Lack of qualified resources
  • Lack of management support
  • Poor estimating
  • Inexperienced project manager

90
Tools to Aid in Risk Identification
  • Decision Support Systems
  • Expected value measures
  • Trend analysis/projection
  • Independent reviews and audits

91
Six steps to risk management are
  • Identification of the risk
  • Quantification of the risk
  • Prioritizing the risk
  • Developing a strategy for managing the risk
  • A contingency plan
  • Project sponsor/executive review
  • Taking action

92
The Disaster of Applying the 10 Solution to
Project Estimates
  • 10 is taken from every on-going project to
    create a budget out of thin air
  • The result is havoc on top of chaos
  • Most high-level executive committees do not
    realize the impact of adopting the 10 solution
  • A REDUCTION IN BUDGET MUST BE ACCOMPANIED BY A
    TRADEOFF IN TIME OR PERFORMANCE

93
The Disaster of the 10 Solution, Contd
  • 90 of the budget generates 10 of the desired
    service or performance levels and the remaining
    10 will generate the last 90 of the desired
    service or performance
  • If there is FAT, i.e., padding, it may, however,
    be possible to sustain a cut in the project
    budget without major consequence
  • Most projects do not have FAT

94
Cost vs. Performance
  • I much prefer the word performance to quality
    here
  • A 10 reduction in cost can be expected to
    produce much greater than a 10 reduction in
    performance

95
More on the 10 Solution
  • 10 reduction solutions should be undertaken only
    after a careful impact study has been completed
  • A far better choice is for the executive
    committee to cancel or de-scope some projects in
    order to release funds

96
14.19 Life-Cycle Costing (LCC)
  • These are the total costs to the organization for
    the ownership and acquisition of a product over
    its full life
  • Especially appropriate for in-house software
    development projects, but is used in some
    (outhouse) contracted projects as well

97
Life-cycle cost breakdown
  • R D Costs (Definition, Analysis)
  • Production cost (Design)
  • Construction cost (Programming and testing)
  • Operation and maintenance cost
  • Product retirement cost

98
Life-cycle costing process
  • Define the problem
  • Define the requirements of the cost model being
    used
  • Collect historical data-cost relationships
  • Develop estimates and test results

99
Successful applications of LCC will
  • Provide downstream resource impact visibility
  • Provide life-cycle cost management
  • Influence RD decision making
  • Support downstream strategic budgeting

100
Estimating Methods for LCC
  • Method choice is based on the problem context,
    operational considerations, etc.
  • Informal estimating methods
  • Judgment based on experience
  • Analogy
  • SWAG method, ROM method
  • Rule-of-thumb method
  • Formal estimating methods
  • Detailed (from industrial engineering standards)
  • Parametric

101
Figure 14-18
  • For every 12 DOD puts into RD, 28 are needed
    downstream for production and 60 for operation
    and support
  • After Conceptual definition and
    demonstration/validation, 85 of the lifecycle
    decisions are made and cost reduction
    opportunities are down to 22

102
14.20 Logistics Support
  • A frequent occurrence in software development
    where the developer is paid to provide
    after-market support in the form of operation and
    maintenance on the product (deliverable)
  • Recall that after the design phase 85 of the
    deliverables life-cycle cost has been committed
    and the majority of the total life-cycle cost is
    still ahead gtgt 60

103
Performance metrics for Products requiring
Logistics Support
  • Suppportability--the ability to maintain or
    acquire the necessary human resources to support
    the system
  • Readiness--measure of how good we are at keeping
    the product performing as planned and how quickly
    we can make repairs during a shutdown

104
Ten elements of logistics support
  • Maintenance planning
  • Manpower and personnel
  • Supply support
  • Support equipment
  • Technical data
  • See page 765
  • Training and training support
  • Computer resources support
  • Facilities
  • Packaging, handling, storage and transportation
  • Design interface

105
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106
Estimating --
  • An iterative process
  • Definition, Analysis, Design
  • After Definition, 50-100 off
  • After Analysis, 25-50 off
  • After Medium level design--within 10
  • A good WBS is absolutely essential to do
    estimating

107
Estimating Techniques
  • Professional Judgment
  • Developer estimate
  • History (database)
  • Formulas

108
Use of Professional Judgment
  • Based on WBS, an expert judgment estimate is made
    for each work package
  • Amazingly accurate when experts are available
  • Often, however experts arent available

109
Developer Estimate
  • The programmer assigned to the work package will
    make every effort to complete the task in the
    time he estimated it would take

110
Use of History Database
  • For this to work, your firm must keep a history
    database
  • The database should record how long each task
    took and who did the task
  • Break new projects up into tasks that have a
    history database
  • 8 to 1 productivity ratio between best to worst
    professional

111
Questions, Contd
  • How much of the total time does Brooks devote to
    Definition, Analysis and Design?
  • 1/3
  • How much time to coding?
  • 1/6 to Coding
  • How much time to testing?
  • 1/4 to component test and early system test
  • 1/4 to total system test
  • So how much time are you going to devote to
    testing in your projects?????

112
Use of Formulas
  • COCOMO--project cost, effort, schedule, staffing
    for each of the phases
  • Preliminary design
  • Detailed design
  • Code and unit test
  • System test
  • COCOMO was developed by Barry Boehm in
    1981--COnstructive COst MOdel

113
Inputs to COCOMO
  • Monthly cost of staff involved
  • Factors indicating the general level of
    complexity of the software
  • Programming practices and tools used
  • Experience of staff
  • Lines of LOSC--rendering COCOMO unusable

114
Function Points
  • A user input
  • User display
  • Peripheral I/O
  • Restructuring data
  • Condition checking
  • Calculation
  • Branching

115
Function point approach--BEFORE YOU LEAP
  • Vendor is Gordon Group
  • It must know how many LOSC are required for each
    function point.
  • It calculates LOSC based on function points it
    knows about and feeds this into the COCOMO
    algorithm

116
Estimacs from CA (Computer Associates)
  • Can take into account modern code generation
    tools
  • Determines effort, but also
  • Hardware required
  • financial break-even analysis
  • risk analysis
  • maintenance costs
  • Expensive gt 20K

117
Estimating Programming Function Points
  • D C ( G J)
  • D is the task duration in person-days
  • C is the complexity of the task
  • G is the assigned persons general experience
  • J is the assigned professionals job knowledge
    factor

118
Complexity
  • Must break task down into its smallest possible
    repeatable functions
  • Then add up the complexity of each function
  • User input, user display, peripheral I/O,
    restructuring data, condition checking,
    calculation, etc.
  • Repeatable functions are called function points.
  • Function points are graded as SIMPLE, COMPLEX and
    VERY COMPLEX

119
Productivity
  • Your average programmer gets a productivity
    factor of 1 for G
  • Slower programmers get factors gt 1
  • Faster programmers get factors lt 1

120
Formula method conclusions
  • Will work if you develop accurate factors
  • Can be used for any task from building a house to
    developing software
  • Depends on how well you granularize

121
Estimating The Analysis Phase
  • Interviews
  • Analyze Existing Documents and Systems
  • Prepare Functional Specification
  • Presentation

122
RATIOS
  • PHASE PERCENTAGE
  • Definition phase -- 10
  • Analysis phase -- 20
  • Design phase -- 10
  • Programming -- 20
  • System test -- 17
  • Acceptance -- 7
  • Operation -- 16

123
This breaks down to
  • PLAN -- 40
  • BUILD -- 20
  • TEST -- 40

124
Another Rule of Thumb
  • The time to design, document and code a module
  • equals the time to debug it
  • According to Gildersleeve

125
Can you use RATIOS for Forecasting?
  • Suppose you found that it took 20 days to do
    definition.
  • How long, based on ratios will it take to do the
    project?

126
Estimating Rules
  • Never use inexperienced persons to estimate
  • Get group estimates if possible
  • Never force an estimate on a programmer
  • Never take an average of different estimates
  • Granularize down to one week or less
  • Always add for contingency
  • Always quote a range when giving estimates

127
Conclusions to Estimating
  • Our weakest talent
  • Estimating is iterative
  • Estimating is still an art

128
Scheduling --
  • Also assists with estimating, especially when PM
    software is used

129
PM software supports
  • WBS
  • Gantt
  • PERT
  • Calendar(s)
  • Resources and their assignments

130
PERT
  • Use activity on node approach
  • doesnt require dummy activities
  • Understand what float is--it is slack
  • Critical path is the longest path
  • shows precedent activities, relationships
  • doesnt show what will be done when, by whom

131
Resource allocation
  • Assign tasks to individuals whose skill level
    suits the task
  • Assign similar tasks to the same person
  • Assign time-critical tasks to your most reliable
    people
  • Assign tasks that communicate to the same
    individual to minimize peoples interaction
  • Dont assign too many different tasks to any one
    individual

132
Reducing task duration by adding manpower
  • Add 20 direct time for each additional member on
    a professional team
  • If it takes 10 person days for one person, it
    will take 12 person days for two people, 14.4
    person days for three people, etc.

133
Cost effects of adding resources
  • More resources, gets the project done sooner,
    USUALLY
  • But it also costs more
  • The PM must come up with the best balance,
    depending on the priorities set by management or
    the user

134
Shortening the duration of projects
  • Fast tracking
  • Crashing
  • Adding resources to the critical path
  • Allowing your current CP teams members to work
    overtime

135
Crashing projects
  • Crash tasks on the critical path only, only as
    long as no other path becomes critical
  • If other paths become critical, the analyst must
    crash those as well

136
Gantt Chart
  • a time bar chart
  • Invented by Henry Gantt in 1910
  • Determine the units of time
  • Mark all known calendar events at bottom
  • Schedule each activity from PERT

137
Use three sets of Gantts
  • one for yourself alone, with all float and
    contingency visible
  • second for the individuals involved--their
    resource Gantt, contingencies hidden
  • third for distribution to upper
    management--contingencies hidden
  • Include a 10 contingency into all estimates

138
Conclusions to Scheduling
  • Use PM software--worth every penny
  • Do at least one PERT and one GANTT manually, just
    to get a feel for the process

139
Recitation
  • What is the probability of completing a project
    by its estimated completion time??
  • What is the formula for calculating the
    completion time for a PERT network?
  • What is the formula for calculating the standard
    deviation of the completion time for a PERT
    network?
  • Name some processes that are part of project
    integration management

140
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