Time Management

Creating Effective Information Systems

Session 5

Time Management

Abeetha De Silva

April 12, 2023 Session 5- 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


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.


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


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.


Critical path methodThis 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.


Activity sequence/network diagram


ES EF

LFLS

Float

ES-Early StartEF-Early FinishLS-Late StartLF-Late Finish


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.


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.


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


Dependency Finish to start (FS) A FS B = B can't start before A is

finished.


Finish to finish (FF) A FF B = B can't finish before A is

finished


Start to start (SS). A SS B = B can't start before A

starts


Start to finish (SF) A SF B = B can't finish before A

startsRare relationship


Exercise Activity A can start immediately and has an

estimated duration of 3 weeksActivity B can start after activity A is completed

and has an estimated duration of 3 weeksActivity C can start after activity A is completed

and has an estimated duration of 6 weeksActivity D can start after activity B is completed

and has an estimated duration of 8 weeksActivity E can start after activity C and D are

completed and has an estimated duration of 4 weeks


Draw network diagramCritical path?Float of activity 3?Float of activity 2?Total float of A-C-E?What is C’s duration get

increased to 14?


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


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.


3). Three-Point Estimatesa = the best-case estimatem = the most likely estimateb = the worst-case estimate.E = (a + 4m + b) / 6


4). Expert JudgmentJudgment 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.


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.


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.)


Schedule compressionOptimizing activity lead-lag

times, Fast-tracking, Crashing Cut ScopeReduce Quality


Fast TrackIn which phases or activities normally

performed in sequence are performed in parallel.

Start development before the designed is approved

May lead to reworkRisk is highOnly works if activities can be

overlapped to shorten the duration


CrashEmployed 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.”


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 increasesRisk increasescrashing 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.


Exercise – Crashing Cost


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


Example PPT_Crashing.pdf


Reduce ScopeCut Quality

Advantages and Disadvantages?


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.


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.

LagA 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


Artifacts Sample project schedule with MS

projectMilestone charts ->Report to MgtNetwork diagrams -> show

dependenciesBar charts ->Track progress of

the team


Your effortPractice network diagram

calculationsPractice Crashing calculationsStudy estimation techniquesStudy artifacts of time

management


References http://faculty.cbpa.drake.edu/bmeyer/web

m120/PPT_Crashing.pdf

http://www.cob.sjsu.edu/davis_r/courses/QBAreader/prjcrsh.html

http://examples.oreilly.com/9780596102340/hfpmp_ch06_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

http://faculty.cbpa.drake.edu/bmeyer/webm120/PPT_Crashing.pdf

http://faculty.cbpa.drake.edu/bmeyer/webm120/PPT_Crashing.pdf







Time Management

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