Calculating Critical Path with Forward and Backward Pass - Key Concepts in Project Management

This video delves deeper into calculating the Critical Path on your Schedule Network Diagram by using the Forward and Backward pass. The steps are:
1. Note the task durations
2. Perform the forward pass to get early start and finish dates
3. Perform the backward pass to get late start and finish dates
4. Calculate float as Late Start minus Early Start
5. The critical path is the path with zero float
#PMP #PMBOK #CAPM #ProjectManagement
See all the Project Management Key Concepts (tools & techniques from the PMBOK Guide): • PMBOK Key Concepts for...

[@Bell-uf9fn]

Hey David! I just wanted to say a huge thank you for your help in explaining the process and providing an example. I was able to create my own version based on your fantastic example. I really appreciate your videos, and I've been sharing them with my PM colleagues too. You're really good at explaining things in a clear and concise way. So, thanks for taking the time to make these videos and sharing your expertise - it's really helped me out a lot. Thanks again!

[@ShihanMeegasdeniya]

My friend. You have no idea how helpful this is. I appreciate this from the bottom from my heart. This helped me to do my pm assignment. Thanks again. ❤

[@Canadianehhhhh]

Thank you for explaining this 100% better than the garbage instructions I received from my project management essentials course at SAIT.

[@MrSilviut]

So many other videos just ignore the plus one minus one thing which makes it so confusing. Thank you for explaining that. Well done.

[@andreanberry4273]

Hi David - For people new to this please announce that you are using the "accepted convention of the project starting on Day 1." I was confused until I saw it on page 211 in the PMBOK 6th Edition. I couldn't figure out where you were getting the number 1 from. These are excellent videos by the way! Thank you so much!

[@videogamesare1]

Thanks David, this helped explain the backward pass very clearly.

[@afshanlakdawalla]

Absolutely made simple...thanks so much!

[@kevinjamal836]

You've made this so simple!! Thanks man

[@konsichguyita5246]

Wow you described this easiest possible way. Thank you!

[@LekhaJD]

Thank you! Your explanation easily clarified a lot of my doubts.

[@jadwigapolak2161]

Very well explained!

[@sargamkapoor1899]

All your vides are great and so helpful

[@london12327]

You made this look very simple !!

[@mdshahzebrahman7223]

Very helpful, thanks!

[@schiefele5514]

You are the best, better than my professors!

[@user-xk6eq4ov9c]

Excellent way of teaching

[@charlotteybradley7579]

David, You are amazing. Your explanation was so much better than.... I wont mention any names 😀🤣

[@myramyra2]

Great breakdown explanation. New subscriber

[@zuzanalima8742]

Hello David, thank you again for all your great videos, you are doing for the PMP students. Not using anythig else now and its very efficient! 🙂But the only thing I am struggling now is to manage the time with the Diagrams questions (the Critical path questions and other one when you need to fill in all the boxes or do longer calculation. If I have in avarage 3 min for quetion, there is no change I can do it. Do you have any tips how I can improve the speed of solving these questions?? I am pretty sure, other students have the the similar problem. Thanks a lot!

[@nimmadhillonz]

Hello David, great video, you really make it clear. The only think which through me off in your explanation is that you are using the +1 and -1 for the ES and EF. Is that necessary? In other explanations they didn't do it. Thanks for the answer!

[@davidmclachlanproject]

Yes you are right, they are not needed and it's simpler without them. I have adjusted this in my course 🙂

[@mopremo]

Does that mean you made a new video explaining it without the +1 and -1? 😊

[@YogeshPatil-db2sc]

Amazing ty

[@TheLilboy6]

Love you mate

[@wflzoom6219]

Whats been throwing me for a loop on these CPA's I have been watching a few, and the -1 and +1 to compensate for the starting ES of 1, instead of zero. is there a reason why the first activity ES in some diagrams starts with 0, and others with a 1 ? or is this just preference?

[@mopremo]

I had the exact same question!

[@Alldidas]

@@mopremo Same, I think the best practice is to utilize 0 as your earliest start. Typically everything else starts with 0

[@Alldidas]

@@mopremo Your early start on your second task should match the earliest finish on your first.

[@mopremo]

@@AlldidasThank you!

[@MrAbitha123]

Hi David, I am preparing for the PMP exam, and your videos have been incredibly helpful! I have a question, In the video, you said that the Early Finish (EF) date is calculated using the following formula: EF = ES + Duration - 1, however, the PMI website states that the EF date is calculated using the following formula: EF = ES + Duration Which formula is correct to use for the PMP exam? Thank you for your time and consideration. I appreciate your help.

[@garrettbell8419]

the plus one and minus one is just compensating for starting the first activity at '1' instead of '0'(including the work done in day 1 in your duration). It confused me as well initially. I hope this helps.

[@yuliiavenhlovska9028]

Can you please explain how the duration was calculated for activity 2? You calculated 4-3-1

[@davidmclachlanproject]

Do you mean the late start during the backward pass? It is the late finish minus duration plus one: 15 - 5 + 1 = 11. Durations themselves are just estimated at the beginning 🙂

[@Ola92408]

How can you answer this kind of questions quickly on the exam without overthinking? Do you have any tips or that? Thank you.

[@davidmclachlanproject]

With these, there won't be many questions on it (I had around 2-3 and that was before the new Agile format). They're mostly around either critical path (just calculate the longest overall path) or float (a task's late finish minus its early finish). With that, plus the general knowledge of it (i.e this video) you should do fine 🙂

[@Ola92408]

@@davidmclachlanproject thank you. I'd practiced it on paper using your way and it totally makes sense. Thank you for the great video!

[@calciumdd7696]

this helps me prep before my exam hahah

[@shehab976]

Is that gonna work all the time?i have examples that has negative floats

[@davidmclachlanproject]

Good question. I've had a look at your video - love your program! Great stuff. For that, it is a normal PERT diagram with no ES or LS etc, you can just add up the shortest path (e.g. 1, 4, 7, 9). Using a schedule network diagram, you should have ES and LS, and I can't think of any situation where your late start would be BEFORE your early start (and hence, a negative number). Especially if doing the forward and backward pass first. I may be missing something?

[@shehab976]

@@davidmclachlanproject sir,those were (ls,lf,es,ef) in the image too,u just need to increase the text size at top of the app,i updated the app several times,its no more exactly that one in the video...bt i am stuck finding critical path

[@jud3356]

The video seems to be broken? It’s not playing

[@timmyhiggins5220]

I don't understand where he got 15..6 plus 10 equals 16

[@chakekarabo1421]

Same here because in my understanding it should be ES plus Duration to get EF

[@agapeagapeone]

🤣🤣🤣 4:29

[@pushpanaorem4371]

you miss explaining certain thing. Please make sure u explain everything at least what u have displayed on the screen..forward and backward pass explanation is not clear

[@zuzanalima8742]

Hello David, great video, you really make it clear. The only think which through me off in your explanation is that you using the +1 and -1 for the ES and EF. Is that necessary? In other explanations they didnt do it. Thanks for the answer!

[@davidmclachlanproject]

Yes, I think you are right! The way in this video is from the PMBOK guide, but yours is an easier way and it still gets the same outcome 🙂

[@zuzanalima8742]

@@davidmclachlanproject Awesome. Thank you very much for the quick reply. Really appreciated!