3.3.4 Critical Path Analysis Flashcards
critical path analysis
process of planning the sequence of activities in a project in order to identify the most efficient way of completing an integrated task or project, aim is to complete project in short time as possible
information needed for critical path analysis
- activities to complete project
- duration of each activity
- dependencies
features of critical path analysis
- nodes
- activities (events or tasks that link the nodes
- duration (time taken to complete activity
- pre requisite ( activities must be completed before next activity can start)
nodes
(circle represent point in time identified by completion or start of activity) -split into 3, left half = number of node right half split into 2 top segment = earliest start time (EST) bottom segment (shows latests finish time ) (LFT)
bottom always same as top unless simultaneous activity has a node
more than 1 path to a node = need to take highest for EST and lowest for LFT
only 1 node at beginning one at end
rules for critical path
- draw a node
- identify task with no pre requisite
- draw a line for each activity and connect to first node (label activity above line) (duration below lines)
- identify next activity with pre requisite
- for 2 or more prerequisites link to 1 node
- repeat task 3-4 until all nodes are drawn
- add the EST
- add the LFT
- identify critical path activities that have LFTs identical to ESTs and represent the longest path between nodes
Earliest Start Time
EST for NEXT task
Latest finish time
LFT for PREVIOUS task
Calculating EST
first node EST = 0
EST calculated from left to right
add duration of activity to EST of previous node
more than 1 activity leads to a node highest figure = new EST
Calculating LFT
give last node of project an LFT = to the EST
work backwards from left to right
subtract duration of activity from LFT
critical path
tasks that cant be delayed without delaying whole project (longest path)
if on critical path LFT =EST
float
duration of an activity can be extended or postponed so that the project still finishes within minimum time
LFT - activity duration - EST
identifying critical path
activities with a float of 0 cant be delayed without delaying entire project
such activities represent “critical path”
on critical path activities have equal EST and LFT
float = o days activity must be completed on time or whole project will be delayed therefore critical activity
identifying all critical activities firm can see which activities must be finished on time = critical path
identifying critical path
activities with a float of 0 cant be delayed without delaying entire project
such activities represent “critical path”
on critical path activities have equal EST and LFT
float = o days activity must be completed on time or whole project will be delayed therefore critical activity
identifying all critical activities firm can see which activities must be finished on time = critical path
for/adv of critical path analysis:
allow business to meet deadlines (especially for time sensitive projects)
some projects expensive and complex CPA = minimise risk of missing deadlines/overspending
allow business to plan resources and plan contingencies (JIT/Lean)
understand critical tasks and which cant be delayed
against/dis of critical path analysis
unforeseen incidents = delays despite CPA (unexpected events)
time consuming
less necessary with experienced company in delivering similar projects (or 1 big project is just a series of small projects)
too much focus on deadline = not enough on quality
only as good as data put into it
business implication of CPA
- efficiency benefits
- business decision making benefits
- time based management benefits
- working capital benefits
efficiency benefits of CPA
increase efficiency = decrease time taken to complete project = reduce costs
business knows when activity due to take place
control and review (monitor progress against original plan)
business decision making benefits of CPA
managers involved in planning and decrease risk of delays/other problems
detailed info to customers = improve relationships
used to change allocation of resources or order of events
time based management benefits
estimate minimum time to complete project identify activities that cant be delayed
resources allocated at appropriate time
activities carried out simultaneously
working capital benefits of CPA
organisation plan when needs particular resources
know when stock needed and therefore hold lower stock levels
problems with CPA
can be fixed and some managers = dont want to move from fixed sequencing
complex activities = difficult to represent accurately on network
project has to be managed and monitored all the way through and not just at the end
if done too quick = reduction in quality
evaluation of CPA
planning and project management tool
helps ensure project is completed as quick as possible, resources used efficiently but it does depend on accuracy of the information used
just drawing a CPA doesnt ensure project runs to plan, most project encounters delays/unexpected = managers need CPA to monitor project and take swift action to rectify problems
