3.3.4 Critical Path Analysis

Question 1

critical path analysis

Answer 1

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

Question 2

information needed for critical path analysis

Answer 2

1. activities to complete project
2. duration of each activity
3. dependencies

Question 3

features of critical path analysis

Answer 3

1. nodes
2. activities (events or tasks that link the nodes
3. duration (time taken to complete activity
4. pre requisite ( activities must be completed before next activity can start)

Question 4

nodes

Answer 4

(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

Question 5

rules for critical path

Answer 5

1. draw a node
2. identify task with no pre requisite
3. draw a line for each activity and connect to first node (label activity above line) (duration below lines)
4. identify next activity with pre requisite
5. for 2 or more prerequisites link to 1 node
6. repeat task 3-4 until all nodes are drawn
7. add the EST
8. add the LFT
9. identify critical path activities that have LFTs identical to ESTs and represent the longest path between nodes

Question 6

Earliest Start Time

Answer 6

EST for NEXT task

Question 7

Latest finish time

Answer 7

LFT for PREVIOUS task

Question 8

Calculating EST

Answer 8

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

Question 9

Calculating LFT

Answer 9

give last node of project an LFT = to the EST
work backwards from left to right
subtract duration of activity from LFT

Question 10

critical path

Answer 10

tasks that cant be delayed without delaying whole project (longest path)
if on critical path LFT =EST

Question 11

float

Answer 11

duration of an activity can be extended or postponed so that the project still finishes within minimum time

LFT - activity duration - EST

Question 12

identifying critical path

Answer 12

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

Question 13

identifying critical path

Answer 13

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

Question 14

for/adv of critical path analysis:

Answer 14

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

Question 15

against/dis of critical path analysis

Answer 15

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

Question 16

business implication of CPA

Answer 16

1. efficiency benefits
2. business decision making benefits
3. time based management benefits
4. working capital benefits

Question 17

efficiency benefits of CPA

Answer 17

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)

Question 18

business decision making benefits of CPA

Answer 18

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

Question 19

time based management benefits

Answer 19

estimate minimum time to complete project identify activities that cant be delayed
resources allocated at appropriate time
activities carried out simultaneously

Question 20

working capital benefits of CPA

Answer 20

organisation plan when needs particular resources

know when stock needed and therefore hold lower stock levels

Question 21

problems with CPA

Answer 21

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

Question 22

evaluation of CPA

Answer 22

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