PMP Exam - Critical Path Part 2

[Projamax]

I am new to this and understood this very easily by this video..thanks a lot

[amitmicrosoft2010]

awesome

[shankarwsme]

excellent one, explained very nice and understandably.

[shankarwsme]

excellent one, explained very nice and understandably.

[mcbvalencia0603]

thank you SirGanttalot. i'm a working student and your lectures saved me a lot of time rereading and understanding whenever i have a mental meltdown doing my assignments.

[mjoraid]

why the early start for I is 13 not 9, since it can start after we finish with G, right?

or in this case i have misunderstood the question (Activity I can start after Activity D, G and H) does the comma here indicate an OR or AND relationship?

if its AND then all of them must be completed before we start I,so we take 13, otherwise we take 9.

but since u have chosen 13, then its an AND.

I think i just answered my self.

thanks though.

[shankhawaramprashant]

Simply the best explanation i have heard! Made the CPM topic both interesting and easy to understand!

Thanks SirGanttalot!

[metallica929]

In my book it says that critical path is the path where the ES and LS are equal for all activities. That's not the same as what you said: longest duration.

[SirGanttalot]

Your book and my video are both correct. Per my video, where there is Zero Float/Slack, the item is critical. And if ES and LS are the same, then LS minus ES will be zero, making the item critical. So one charecteristic of the CP is that all tasks along it have Zero Float/Slack. ANOTHER characteristic of a critical path is that is is the longest duration path through the network. So the two statements are flipsides of the same coin, not contradictions. Hope this helps.

[metallica929]

@SirGanttalot Thanks for the reply. Appreciate it.

[eintoronto40]

This was better than my exam prep class.

Thanks

[jodisapphire]

@SirGanttalot This has proven to be quite helpful thank you. I'm having trouble constructing an activity network I got for my exam and I'm hoping u can help me. So activity A, B, C have no predecessors, D follows C, E follows B and D, F follows A and E, G follows A and E, H follows F, I follows G, J follows C, and K follows H and I. I'm okay with the calculations but I just need help with the construction of the activity. Thank you.

[SirGanttalot]

I have a solution.......feel free to email me separately (my email address is on my Channel page) and I can either FAX you or send a PowerPoint).

[Fongj1821]

Hey SirGanttalot i dont understand one part and hope you can reply me ASAP.... for the joint part in the backward pass for section C and A how did u actually get your 6 and 2 value for C and 2 and 0 for A

[SirGanttalot]

Hi.  Going backwards, for both C and for A there are TWO ways to get to the box. You can get to C from either E or from F. So there are 2 possible numbers for the LS for C. You would get 6 if you came from E, and 2 if you came from F. You can only use one number, so you use the lowest, 2. Same thing for A. You can get to A from B or from C. Coming from B gives you a number 3, coming from C gives you the number 0. So again, the rule is choose the lowest, 0. Hope this helps.

[Fongj1821]

Hey SirGanttalot i dont understand one part and hope you can reply me ASAP.... for the joint part in the backward pass for section C and A how did u actually get your 6 and 2 value for C and 2 and 0 for A

[hmpeter]

Than You very much, your videos helped me a lot!

After watching them things seem to be so obvious that i dont know why i did not understand them in the first place. ;-)

[pedroelmacho]

Hi SirFanttalot, thanks for sharing your knowledge.

In this video though, you did not get the total length of the path, since you only calculate STARS, but I finishes in 13+2, so the EF and LF is 15. This means that the total lenght of the critical path is 15. Am I right?

Thanks!

[SirGanttalot]

Yes that's right. The EF is the ES + the Duration. The LF is the LS + the duration. In both cases this is 15 for the last activity, so the schedule duration is 15. When you do the Forward Pass and Backward Pass, it might help to show ES, EF, LS, LF in all of the boxes. If that makes it easier for you, use that technique. Regards.

[pedroelmacho]

Hi SirFanttalot, thanks for sharing your knowledge.

In this video though, you did not get the total length of the path, since you only calculate STARS, but I finishes in 13+2, so the EF and LF is 15. This means that the total lenght of the critical path is 15. Am I right?

Thanks!

[doust]

hie. grt vid.

u no for the forward pass rite. y re we nt using c as a join.

is e separate for c or together which is y g is being used

or re we using g because it is at the end like h and d ???

[gembi100]

thanks exclent, much usefull thnks again

[notquitefamous]

Thank you so much! I had so much trouble understanding the backward pass and searched forever online for help but none of them helped me understand has much as this one!! Thank you! A+

[mickmurphy100]

Excellent tuition, thank you.

[blacon9]

Very well done with these videos, great help to everyone.

[testpmp]

Great Videos on Critical Path. Thanks a lot. Made it so easy for all of us. Most concise and simple explanation I have come across. Will love to hear more from you

[ankercho]

Ty so much! I was trying to understand it for hours and now after your 10 mins video i finally realized what is it for :) Ty Ty Ty Ty Ty :)))

[pculver]

This was the clearest, simplest explanation of CP and float I've ever seen. Thanks.

[Intermilano99]

Alright Thank you Sir much appreciated, however I do have another question, but will do some research before asking :) thank you again

[Intermilano99]

ES of activity A=0? is not suppost to be 1? as it is the first in the path? thank you

[SirGanttalot]

Some approaches do set the ES of the first activity to 1. If you take that approach, you calculate the EF of that activity by using the formula EF = ES + Duration - 1. Then set the ES of the SUCCESSOR to be EF of the PREDECESSOR + 1. So you keep adding 1 and then subtracting it again at each step. On the backward pass you take a similar manipulation, this time subtracting 1 and then adding it back again. None of this is needed if you start at 0. However, either approach is fine.

[dt55805]

Ok since both approaches are fine (starting your first activity in the forward pass with a value of 1 or 0), which one will the test use? and can I use yours for test?

[SirGanttalot]

Most likely on the PMP test you will not have a question that asks, for example, "What is the ES for Activity NNN?". The reason is exactly the one that prompted your question...there are two different approaches that work, and therefore two possible answers. Instead, questions might be to give you a list of say, 6 tasks, showing the ES and LS for each of them using real dates. Then you might be asked which task is critical, or which has most slack.

[danielvarjao]

Thank you so much, really good video

awesome

[mrohailiqbal]

Thank u very much Sir. It helped me a lot to pass through my University exam. :)

[rishitesting]

Awesome...Sir you are great..

[Msylladiby]

SirGanttalot you are a genious! this is great! I final know how to do this.

[sensationfreak]

thanks for the really good and simple video. Its good for even the IB

[Faisal9033]

Thank you for the wonderful and simple style of teaching. It is highly appreciated!

[TheBreze]

Thanks. It helps me to better understand the concept!

[SirGanttalot]

Thanks for the feedback! There is always a chance that you may need to calculate ES, LS, EF, LF. In this Part 2 Video we calculated ES and LS, the Earliest each task can Start, and the Latest each task can Start without extending the project duration. To calculate EF or LF, simply add the task duration to ES or LS, i.e. EF = ES + Task Duration, and LF = LS + Task Duration. I hope this helps.

[dt55805]

@SirGanttalot Please update your slide set with the EF and LF. Your slides are spot on. Heads First PMP has a good Critical Chain Learning Process as well for figuring this out, but yours is the best...if it had the EF and LF:)

[lewissteve7]

How do you draw a diagram showing tasks with a lead or lag time and then calculate the ES or LS?

[SirGanttalot]

Part 1 response: To draw lags you could replace the lag with an activity actually named "Lag", or use a real name such as "Wait for paint to dry". Alternatively you could add the words "Lag +3 days" for example above the arrow connecting the two tasks. To draw leads, you could either show the connector arrow as a line that turns back underneath itself before turning to go forward again and also label it as "Lead -3 days", or leave it as normal connector but still label it as just described.

[SirGanttalot]

Part 2 response: You may have seen in Microsoft Project, Leads and Lags in the Network Diagram don't show up as ANYTHING other than adjustments to ES and LS. So basically to calculate ES and LS in a lead/lag situation you can do what MS Project does, i.e. modify the predecessor duration by adding time for lags, subtracting time for leads. That way the formulas mentioned in the video should work. Try it out in a simple situation with 4-5 activities to see what approach works best for you.

[lewissteve7]

Thanks for the response SirGanttalot, don't suppose you want to take my exam for me do you!?

[sevensteps007]

Seek284, probably we will have to fight for becoming the biggest fan.

Sir Ganttalot, I have attended PM classes in the undergrad life, in work life and in PG studies, in class rooms and distant learning. I have never experienced an explanation with this clarity. You are definitely gifted.

In summary, 5 Star work and I look forward to learning a lot from you.

[Crazynu]

this was very helpful.thank you so much.

[BM79ZHG]

excellent.

[ssupnel]

Thank you very much...

[Seek284]

Sir Ganttalot I am your biggest fan,the vid is up to your usual excellent standards.