1. Creating Effective Information Systems
Session 5
Time Management
Abeetha De Silva

2. Why is Project Time
Management important?
 According to research on average 82% of
projects overrun time scales
 Issues concerning project schedules cause
the most number of conflicts on projects
 Time variable is one of the project variables
with the least amount of flexibility
To avoid delays and increase the success
rate of the timely completion of projects we
need to do project time management
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3. Effort vs. Duration:
 How much time do you need to
complete this task?
 It will take 10 hours to complete it‖
or
―It will be completed in 10 hour.
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4.  Effort=Work
 Effort is the actual time required to
complete the task
 Duration is the total amount of time in
which the user has to complete the
task
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5. Network diagram
 A Work breakdown Structure ( WBS)
allows you to identify groups of activities
that you need to accomplish in your
project.
 However, the WBS does not show the
dependencies or sequence between
these activities.
 A network diagram will allow you to
illustrate this. Once your network
diagram is ready, only then can you
realistically start determining your
project‘s schedule.
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6. Critical path method
 This includes determining the longest
path in the network diagram (critical
path), the earliest and latest an activity
can start, and the earliest and latest it
can be completed.
 Critical Path – the longest duration
path through a network diagram.
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7. Activity sequence/network
diagram
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8. ES-Early Start
EF-Early Finish
LS-Late Start
Float LF-Late Finish
ES EF
LS LF
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9.  Early start(ES)
Is the earliest time that an activity can
start. An activity near the end of the path
will only start early if all of the previous
activities in the path also started early. If
one of the previous activities in the path
slips, that will push it out.
 Early finish(EF)
Is the earliest time that an activity can
finish. It‘s the date that an activity will
finish if all of the previous activities
started early and none of them slipped.
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10.  Late start(LS)
is the latest time that an activity can start.
If an activity is on a path that‘s much
shorter than the critical path, then it can
start very late without delaying the
project – but those delays will add up
quickly if other activities on its path also
slip!
 Late finish(LF)
is the latest time that an activity can finish.
If an activity is on a short path and all of
the other activities on that path start and
finish early, then it can finish very late
without causing the project to be late.
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11. Network diagram cont..
 Slack/Float = LS –ES or LF-EF
 EF=ES+Duration
 LS=LF-Duration
 ES = Calc. time at the beginning node
 LF = Calc. time at the ending node
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12. Dependency
 Finish to start (FS)
 A FS B = B can't start before A is
finished.
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13.  Finish to finish (FF)
 A FF B = B can't finish before A is
finished
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14.  Start to start (SS).
 A SS B = B can't start before A starts
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15.  Start to finish (SF)
 A SF B = B can't finish before A starts
 Rare relationship
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16. Exercise
 Activity A can start immediately and has an
estimated duration of 3 weeks
 Activity B can start after activity A is completed
and has an estimated duration of 3 weeks
 Activity C can start after activity A is completed
and has an estimated duration of 6 weeks
 Activity D can start after activity B is completed
and has an estimated duration of 8 weeks
 Activity E can start after activity C and D are
completed and has an estimated duration of 4
weeks
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17.  Draw network diagram
 Critical path?
 Float of activity 3?
 Float of activity 2?
 Total float of A-C-E?
 What is C‘s duration get increased to
14?
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18. Estimate techniques
1).Analogous estimates:
 analogous estimates are based on a previous project(s)
within the organization. This estimate is often the earliest and
most convenient one to gather. Because of that it is often
used to justify a project and for project chartering.
 Top-Down
 Initial Phases
 Quick
 Less costly
 Less accurate
 Historical Data
 Expert Judgment involves
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19. 2).Parametric Estimate
 An estimating technique that uses a
statistical relationship between historical
data and other variables
 (for example, square footage in
construction, lines of code in software
development) to calculate an estimate
for activity parameters, such as scope,
cost, budget, and duration.
 This technique can produce higher levels
of accuracy depending upon the
sophistication and the underlying data
built into the model.
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20. 3). Three-Point Estimates
 a = the best-case estimate
 m = the most likely estimate
 b = the worst-case estimate.
 E = (a + 4m + b) / 6
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21. 4). Expert Judgment
Judgment provided based upon expertise in an
application area, knowledge
area, discipline, industry, etc. as appropriate for
the activity being performed.
Such expertise may be provided by any group or
person with specialized
education, knowledge, skill, experience, or
training, and is available from many
sources, including: other units within the
performing organization; consultants;
stakeholders, including customers; professional
and technical associations; and industry groups.
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22. 5). Bottom-Up estimates
 A Bottom Up analysis is a technique to improve the
accuracy of the overall project estimate. This technique
requires the project team to decompose the work into
very small work packages.
 Generally, the smaller the project activity, the easier it is
to estimate because the work scope is very small. All of
these estimates of small activities are added up into
subgroups and finally into the project total.
 The advantage of this technique is that the estimate is
usually more accurate since the work is better
understood. The disadvantages of this technique is that
it is very time consuming, and it may be impossible to
decompose activities that cannot be easily defined.
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23. 6).Published Estimated Data
 Published Data Estimating is an excellent technique for those
activities for which there is published data. In this
technique, the activity is compared to the activities for which
data exists and the actual cost or durations of the closest
comparable activity is selected from the data and used as the
estimate.
 The advantage of this technique is that it is very accurate
when the project conditions match the conditions under which
the published data was generated. The disadvantages are
that data does not exist for many activities and that the
published data that does exist is based upon the
characteristics of the organizations who compiled and
published the data - which may not correspond with your
organization's characteristics. (For instance you may have
individuals on your project who are either much more or much
less experienced than those who were in the projects
comprising the data.)
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24. Schedule compression
 Optimizing activity lead-lag times,
 Fast-tracking,
 Crashing
 Cut Scope
 Reduce Quality
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25. Fast Track
 In which phases or activities normally
performed in sequence are performed in
parallel.
 Start development before the designed is
approved
 May lead to rework
 Risk is high
 Only works if activities can be
overlapped to shorten the duration
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26. Crash
 Employed in those cases where
activity overlap is unacceptable.
Crashing critical path activities is the
practice of reducing their duration
while allowing them to remain in
series, essentially the ―F-S
arrangement.‖
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27.  By reducing the duration of a critical path
activity it may be necessary to apply
additional resources such as
personnel, extra equipment, or
supplementing with outsourced
resources.
 Cost increases
 Risk increases
 crashing should be practiced only when
the project schedule completion date is
of a higher priority than the project cost.
The priorities should therefore be clearly
delineated in the authorizing project
charter.
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28. Exercise – Crashing Cost
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29.  Assume project has a project float of 3
months, which activity(s) presented
above would you crash?
 Its J and N.
 If the ‗float‘ is not there:
◦ First determine the critical path
◦ Select the activities with lowest cost
◦ Determine the crash time
◦ IF there are 2 critical paths then need to
crash both together
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30. Example
 PPT_Crashing.pdf
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31.  Reduce Scope
 Cut Quality
Advantages and Disadvantages?
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32. Terminology
 Milestone and milestone chart
 A milestone is a significant event in the
project, such as an event restraining future work or
marking the completion of a major deliverable or
phase. Duration is zero.
 Lead time is used to represent partial
dependencies. By using lead time, certain tasks
can overlap by a fixed amount or by a percentage
of the predecessor task.
 For example, testing can start when 30% of coding
is finished. It can be thought of as the predecessor
task getting a head start, or lead, before the
successor task starts. lead time is also referred to
as negative Lag.
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33.  Float (Slack )
The float of an activity is the amount of time that the
activity can be delayed without causing a delay in the
Project.
 Lag
A modification of a logical relationship that directs a delay
in the successor task. For example, in a finish-to-start
dependency with a ten day lag, the successor activity
cannot start until ten days after the predecessor has
finished.
 An example where a lag makes sense is that you're
painting a house, you paint the first coat (predecessor
task), and then you have to wait a day (that's your
lag), and then you can start with the second coat
(successor task).
 Negative float means behind the schedule
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34. Artifacts
 Sample project schedule with MS
project
 Milestone charts ->Report to Mgt
 Network diagrams -> show
dependencies
 Bar charts ->Track progress of the
team
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35. Your effort
 Practice network diagram calculations
 Practice Crashing calculations
 Study estimation techniques
 Study artifacts of time management
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36. References
 http://faculty.cbpa.drake.edu/bmeyer/webm120/PPT_Cr
ashing.pdf
 http://www.cob.sjsu.edu/davis_r/courses/QBAreader/prj
crsh.html
 http://examples.oreilly.com/9780596102340/hfpmp_ch0
6_errata_pp257-265.pdf
 http://www.projectmanagementguru.com/estimating.htm
 (PMBOK® Guide)—Fourth Edition ... PMI
Publications, 14 Campus Boulevard, Newtown
Square, PA 19073-3299 USA
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