Lecture 3 Flashcards
what are work packages?
a subset of a project (mini project) that can be assigned to specific resources and produces a deliverable within the project
what should work packages be?
small enought ot require the same resources throughout keeping track of WPs ggives a good view of the projects overall status,
large enough to lead to a verifiable outcome and form independent units of work with distinct start times and resources
what are the three types of actrivity project breakdowns
major activity groups
activity subgroups
individual work pacakges
what are the three types of breakdown
functional breakdown
physical breakdown
activity breakdown
when would a functional break down be used
when the project takes place in a functional org.
when the PM has little authority over team members in functional units
when would a physical breakdown be used
when the project decomposes naturally into independent modules (construction, softrware physical products)
when would an acitivity breakdown be used
project oucome is a service
what do node diagrams take into account
Task dependency on the completion of other tasks
what is EST, LST in CPA
critical path analysis
earliest start time: all predecessor tasks started asap
LST: project completion delayed, started latre
what is the total float
difference between LST and EST for each task, max time that task can be delayed without affecting project duration,
what does it mean if total float is zero?
activity is critical - lies on critical path.
what method can be used to calculate EST
forward pass method
add timing of each event + timing of predesseccor, to see earliest start time
what can be used to calculate LST
backward pass, same principle as forward but start at end and work back
task finish must not delay the project completion time
what can be used to visualise project tasks over time
Gantt chart
task list on the ordinate, timeline of the abscicca
how can you translate a gantt chant?
tasks as bars,
milestones as diamonds
precedences as arrows
what are the advantages of CPA and Gantt charts
1`. determines most likely project completion date
- what if analysis possible (e.g. different durations.
- visualises dependencies and tasks that can be run in parallel
- helps to determine critical and non critical paths
- good communication tool to clients, stakeholders etc
what are the limitations of CPA and Gantt charts
- task durations are often difficult to estimate, does not handle resources constraints, may result in excessive multi tasking, can become complex for large projects
what are the problems with CPA and Gantt charts
- expensive
- many tasks cancelled before completion
- average time overrun is 222% of initial estimates
- 52.7% of projects cost on av. 189% of initial estimates
- only 16.2% of projects completed on time and on budget
what is parkinsons law
tasks expand to fill the time available,
-early finish is disadvantagoues, new work, less margin in future
available extra time can be used to polish the result
what is student syndrome?
margins are wasted as task start
- not started before they become critical
- cpa worsens problem through explicit lastest start times
what is murphys law
unexpected will happen for sure
anything that can go wrong will go wrong.
5 reasons there are problems with gantt and cpa`
- estimates include large safety margin
- parkinsons law
- student syndrome
- murpheys law
- cpa encourages multitasking
how can cpa encouraging multitasking be abad thing
time lost when switching between tasks
task priorities - critical non critical
how can we buffer management in critical chain
- estimate task durations
- determine the projects critical chains
- include buffers to protect critical chain
- project control
how can estimating task durations buffer management
- use median task durations to match duration (50%)
no safety added to task duration, remove stigma of late finish
how can determining the projects critical chain buffer management
fixed dates
custom and practise (‘task starts monday’)
no other constrains present = critical path
availibity of resources
what buffers can be added to protect critical chain
- project buffer - protects project being delayed at critical chain - inserted at end of project network
- feeding buffers - inserted at end of task paths feeding critical chain
- resource buffers - inserted when non critical tasks precedes a critical one and both share commojn resource
