networks-project crashing

[Albeno69]

i struggle to get a handle of this concept i understand the critical path EST and LST but dont understand how crashing works. can anyone help me,

[crayolé]

Project crashing involves lowering the duration of events in the critical path which will change the earliest/latest starting times.

In the exam, you'll be given a list of events that can have their time lowered. All you have to do is use those instead of the normal times and redo the EST/LST. Which may or may not result in a new critical path (most of the time it will)

[LFTM]

Can someone please explain crashing in more depth, i don't get it and the essentials book barely covers it,

TIA

[_avO]

Yea I use Essentials and I find it's really pathetic in terms of explaining chapter 24 (looks like it was rushed).

Basically crashing is when a business wants to become more efficient in its operations (maybe by employing another worker or making workers work more productively) which will generally mean an increase in costs. What crashing does is that it lowers the duration of a particular stage in the process of producing a good. Crashing can only be used on paths that are within the critical path. The point of crashing is to see whether it is more or less efficient after determining its effects.

e.g. lets say A to B usually took 10 days, but now it takes 8 after crashing. Assuming A is the beginning of the critical path and B is next in the line (Critical path = A-B-D-F-G). You basically alter the [EST|LST] of B (given that it's only predecessor is A) down 2, making it [8|8] instead of [10|10]. In the end, the finishing time will be reduced by 2 days from [X|X] to [X-2|X-2]

Using the above example, lets alter it and say another path A to C (Where C is a predecessor of E only) takes 9 days. The new critical path can now be seen as A-C-E-F-G. Thus when writing out the [EST|LST] B will be altered from [8|8] to [8|?] and C will be altered from [9|?] to [9|9]. Because of the crashing of the path A to B, it has actually caused the critical path to change and hence you can say that it was not efficient to crash A to B since B is no longer in the critical path wasting business costs and floating the process.

This is basically what I think crashing is just from looking at the Essentials textbook. If anyone sees anything incorrect about this please address it

[LFTM]

Thanks. How do you know how much to crash it by?

[crayolé]

Thanks. How do you know how much to crash it by?

It'll be in the question stem. You'll get a table telling you how much each event can be lowered by