Determine Late Start (LS) and Late Finish (LF) of acitivies in PDM network diagram

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[@Engineer4Free]

Glad to hear it, thanks for letting me know!

[@aidenluke4727]

For my study style, i like concised and simple examples + explanations, you did just that in these tutorials. Tomorrow i have project management test and i understand everything you taught in this lesson. A bunch of thanks and kudos to you sir.

[@Engineer4Free]

Thanks for the feedback, hope the exam goes well!!!

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I don't know why they don't teach it like this in school...they have to make as difficult as possible in the textbook...Thank you for making it easy!

[@Engineer4Free]

Thanks for the feedback. This stuff really isn't that complicated, it just gets complicated for no reason a lot of the time in teaching =/

[@mohammedmj4006]

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[@Engineer4Free]

Glad I can help =) thanks for the comment!

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[@Engineer4Free]

wins all around! glad you like it :)

[@edwardrodriguez8783]

Excellent video!!!! Just wanted to add. You can always calculate the amount of time you can delay an activity by using the following formula: Late Start - Early Start or Late Finish - Early Finish. So for example on Activity B, LS-ES = 5-5 = 0. This means that here you have 0 float or slack and therefore you cannot delay this activity. Pretty much all activities part of the Critical Path has Zero float. In contrast to Activity C, LS-ES = 7-5 = 2. This means you have a float or slack of 2 and you actually can delay this activity by 2 days and it won't impact your total project duration.

[@Engineer4Free]

Hey thanks for the contribution Edward! Yup you're right all activities on the critical path have zero float/slack. This video is an earlier one in a greater playlist, I get into float/slack in videos 13-15 here: engineer4free.com/project-management =)

[@syedhaq12]

Great and excellent work in CPM. After had searched tons of videos, finally came across your video and you nailed it. Thanks from Pakistan.

[@Engineer4Free]

Once again, glad you found the videos Syed 🙂🙂

[@kausalyaakannan7064]

The explanation is straight to the point and the boxes improve my understanding towards this topic. Thanks love!

[@Engineer4Free]

Thanks Kausalyaa!! Do check out the rest of the vids at engineer4free.com/project-management if you haven't already 🙂🙂

[@Thris22]

Thanks mate. You just saved a student's life here.

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Professor= Egyptian mathematics Enginner4free= counting numbers But it is a same concept 😂 Brother your teaching skills are just tooo good than bald professors 👍

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[@Engineer4Free]

Glad I could help 😊😊

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You are a life saver! this was way more helpful than the power point slides my SDSU professor placed for us. Thanks a bunch!!!

[@Engineer4Free]

Glad I could help! You should check out the rest of the PM videos i did at engineer4free.com/project-management =)

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[@Engineer4Free]

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[@Engineer4Free]

Glad to hear it! Thanks for watching =)

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[@Engineer4Free]

Awesomeeee! CPM can be unnecessarily complicated if not explained right. Glad you found the explanation in the video easy to understand!!

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[@Engineer4Free]

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2hours lecture cramp into 5minutes, excellent.

[@Engineer4Free]

=)

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[@Engineer4Free]

haha that's how we do it engineer4free style :p

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Absolute Hero man Thank you.

[@Engineer4Free]

You're welcome, thanks for watching! Check ob the rest of the vids at too at engineer4free.com/project-management if you have some time 👌

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thank you, much more helpfull an easier to understand than my lecturer

[@Engineer4Free]

Glad that I can help =)

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[@Engineer4Free]

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You explained this better than my textbook, Pearson online learning and my professor combined. Thanks. Amazing how people leave this out when showing their work. Like how else am i supposed to figure it out?!!

[@Engineer4Free]

Wow thanks for the compliment! Glad to hear that my videos are helping so much! =)

[@TheACCmy]

This is short and to the point thanks!!

[@Engineer4Free]

Thanks for watching, glad you liked it!

[@kometthegenesis7878]

Wow this is the best explanation of this lesson I have ever heard! Thanks a lot!!

[@Engineer4Free]

Thanks!!! Really happy to hear that =) =)

[@memorablename5187]

This is too easy yet i found it tricky to get my head around, some text books say to add 1 onto each node during the forward pass and minus 1 during the back pass. this is why i was confused but ill just do it this way it makes more sense

[@efeerol2805]

It was very helpful. Thanks a lot.

[@Engineer4Free]

Glad you liked it! The full playlist is here: engineer4free.com/project-management =)

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You are so articulate Thank you because i had someone explain this to me and i felt like a dumbass

[@Engineer4Free]

Thanks Lentie! I know the feeling, so I do try to be super clear 😊😊. Do check out the rest of my PM videos if you haven't already here: engineer4free.com/project-management you might like them

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[@Engineer4Free]

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[@Engineer4Free]

Happy to help, thanks for watching! 👍👍

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[@Engineer4Free]

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[@Engineer4Free]

Glad I could help. Thanks for watching!!! 😁

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[@Engineer4Free]

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[@Engineer4Free]

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[@Engineer4Free]

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Simple, easy. Thanks.

[@Engineer4Free]

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Thank you so much... This is really helpful

[@matthewlong7040]

so helpful compared to my professor!!!!!!! Thank you every much

[@Engineer4Free]

Glad I can help!! Do check out the rest of the vids at engineer4free.com/project-management 😊😊

[@hasithawickramasinghe7153]

Thanks ... much helpful for me

[@Engineer4Free]

You're welcome, again! 😁

[@ThusithaJayakody]

Problem! I'm doing PMP and we are taught to put 1 in the early start of the first activity /activities and put early finish value as , early start + duration -1. So my boxes come essentially the same in all finish values and one incremented in start values. In question papers, when asked the ES or LS of any activity, your values will be wrong. What's this other method. Explain please

[@Engineer4Free]

Hey Thusitha. Both methods are correct. If you're going to be tested starting with an initial ES of 1, then practice with that numbering system. If you're curious as to why there's two numbering systems, then continue reading. My network diagram stars with a zero because my Gantt chart starts with a zero. Watch this video in how I draw Gantt charts: www.engineer4free.com/4/how-to-draw-a-gantt-chart . Notice how my Gantt chart vertical starts counting from zero? I do it that way, because it's more mathematically sensible. Axis normally start at 0 in most maths, but to each their own. So anyways, notice that in that video, 0 represents the beginning of day one. 1 represents the end of day one, and the beginning of day two. 2 represents the end of day two, and beginning of day three, and so on. 0, 1, 2, are just labels associated with real times (and usually two different times to be slightly confusing) but if you're looking at the Gantt chart, it should be clear that each "column" is a day, and the lines (0,1,2,3...) are the points between the days. Aaaany how, I was saying that the numbers 0,1,2,3 are just labels, and one can pick any label to describe a certain time. PMP chooses 1,2,3 where I choose 0,1,2. it's why you're taught to have a -1 in your formula, but overall the logic is exactly the same, and the projects as described by a table of dependencies will be exactly the same, whether we call the end of day one, 1 or 2. Some institutions teach it my way, some teach it the other way. Doesn't really matter, but just follow the convention that your going to be tested on, and understand that some people are going to be following a convention that appears to be off by one. Hope that helps. 🤜🤛

[@ThusithaJayakody]

@@Engineer4Free Thank you for the great detailed explanation. You're so inspiring. It's now clear to me like never before

[@thandolwami1]

thank you so much,this helped me a lot am busy preparing for my exams.

[@Engineer4Free]

Glad it helped! If you haven't already, check out the rest of my PM tutorials here: engineer4free.com/project-management :)

[@scorpioinny24]

Thank you, these videos have been very helpful. what do I do if the network doesn't close?

[@Engineer4Free]

If you have more than one terminal activity then take the highest EF of all terminal activities as the end date of the project. Bring that value into the LF of all terminal activities, and then proceed with the backwards pass as usual 🤜🤛

[@abrahamjohn9060]

Thank you for your video for making it really simple. I was struggling a little :)

[@Engineer4Free]

Hey Abraham glad I could help! If you haven't already, check out all the PM videos I did at engineer4free.com/project-management =)

[@kevig1792]

thx man! better than my class tutor.

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Wow very helpful for my study!

[@Engineer4Free]

Awesome! Make sure you check out all my PM videos at engineer4free.com/project-management

[@catstarr0]

Thank you!!! So helpful!

[@Engineer4Free]

You’re welcome thanks for watching!!! =)

[@ashleykopf404]

This was so helpful! Thank you so much.

[@Engineer4Free]

Awesome! Thanks for letting me know =)

[@divinigraceful]

Engineer4Free Is it possible to have negative LS?

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i am some who love education but lives one of the most lawless gun vessted state in world love to increase my education thank you teacher

[@SUPERPROGOODS]

What is Lag and Lag relationship?

[@Engineer4Free]

I don’t know. Typically the relationships are called Finish to Start, Start to Finish, Finish to Finish, or Start to Start. Lead/Lag may be an aspect of any of them, but I have never hear of a Lag and Lag relationship, sounds like a typo. Check out videos 16-22 here: engineer4free.com/project-management 🙂

[@iTzThis]

When you do the backwards pass, why do you use the smaller number? What's the logic behind this?

[@Engineer4Free]

Pretty much just so you don't violate the successor with the smaller ES. If you brought in the larger one, the EF of the predecessor and the successor with smaller ES would not agree. It turns out bringing in the smaller ES always satisfies the big picture. That's the gist of it, make sense?

[@hotl1kefire]

Thank you!

[@Engineer4Free]

You're welcome!

[@ramatumassaquoi1227]

thanks for a job well done. it was helpful than my leacture

[@Npvp98]

Thank you good sir...well explained.everything .🤟🤟😃.amazing sir.

[@Engineer4Free]

You're welcome, thanks for watching! ☺️

[@TheManubarcafan]

you are a KING

[@Engineer4Free]

+Yusuf Katalony ahahaha thanks :). If you're looking for any more PM tutorials, you can find the rest of mine here! www.engineer4free.com/project-management

[@taylorreid6839]

how do you determine the bottleneck from a PDM network diagram?

[@robinkuederli]

You have to put -1 to each activity in the pmi certificate

[@Engineer4Free]

I am aware of this. The method that I use was the method that was taught to me when I initially studied this in university. If you are pursuing certification, it's necessary to follow the convention used in the program, but at the end of the day, it's just a convention, and the logic is what is important. Both conventions use the same logic despite having a different initial starting number.

[@cettysai5468]

Really helpful thank u

[@Prophetesselishaburgess]

Thank you thank you thank you!

[@Engineer4Free]

You're welcome you're welcome you're welcome!

[@platelet9999]

Why don't you add one day in the forward pass? How can you finish one activity and start the next activity on the same day?

[@platelet9999]

kzbin.info/www/bejne/m4vKp2R4jJafebc This is the correct method as per PMI PMBOK

[@maryscars]

I'm studying for the PE and the reference book just glides over this topic. This explains it perfectly! Thanks!

[@Engineer4Free]

Glad to hear that this is more helpful! Thanks for watching!

[@thomasallison3169]

great video

[@Engineer4Free]

Thanks! ☺️

[@susuteehee]

Thank youuuu!!!

[@Engineer4Free]

Ja welcome!!

[@xt1calendar17]

hi! thanks for your videos!! they are REALLY HELPFUL! but i still can't wrap my head around the logic of picking the smaller number for the late finish of the previous event ._.

[@sai_pranav_karri]

Thanks...

[@Engineer4Free]

You’re welcome!!

[@joejoe4172]

Nice video.Really helpful

[@prabaseelan1999]

You are great.Thank u so much

[@Engineer4Free]

Thanks!!!! 😊😊

[@dtv3804]

Thank you 💙💙💙💙💙💙

[@Engineer4Free]

You're welcome 😊

[@sunglass17]

This is very helpful. Thanks

[@Notrends]

What if A has a predecessor? Would diagram start from a different activity?

[@Engineer4Free]

Yes. Don't be fooled by the choice of names of activities and assume that because the letter A comes first in the alphabet that an activity named "A" must come first. It does in this case, but the ultimate factor in determining the which is the initial activity in the project is communicated to us in the table of dependencies as the activity that has no predecessor. If this was a construction project, the activities wouldn't be named A, B, C, etc... they could be Excavate, Pour Concrete, Framing, Roofing, etc... It is possible for a project to have more than one initial activity (with no predecessors) and/or more than one terminal activity (with no successors), and in that case multiple initial activities all have ES = 0, and for multiple terminal activities you find the largest EF of them and set that as the LF of all terminal activities to begin the backward pass. Hope that clears it up!

[@Notrends]

Engineer4Free thank you for the reply. I have a case that project starts from A and B but they both have predecessors. That's where I got lost. I really appreciate your help

[@emiliadyck7476]

youre awesome!

[@Engineer4Free]

Thanks Emilia!!

[@TheAntonellav]

great tutorial

[@Engineer4Free]

Thanks Antonella

[@marcopeiser]

Helped me a lot :-)

[@Engineer4Free]

Glad to hear it!! 😊

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Dude you’re so nice

[@Engineer4Free]

Haha thanks ☺️

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Thank you sir

[@Engineer4Free]

You're welcome, thanks for the comment!

[@mohammedomarfaruk2837]

very helpful

[@Engineer4Free]

Thanks Mohammed, do tell some friends/colleagues that could also use it =)

[@afrasiabhamid7860]

nice and easily understand

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Thank you♥️

[@ndehstanley1572]

Very helpful. Thank you.

[@Engineer4Free]

+Ndeh Stanley Thanks for the comment! You can find the rest of the PM tutorials I made here: www.engineer4free.com/project-management Good luck studying!

[@thedarkspy99]

Thank you sir, this was very helpful!

[@Engineer4Free]

Glad to hear it, thanks for letting me know!

[@nabilanowrin6356]

thanksssssssssssssssssssss a lot.it was so helpful

[@Engineer4Free]

You're welcomeeeeeeeeeeeee glad to hear it 🙂

[@divinigraceful]

Is it possible to have negative LS?

[@Engineer4Free]

No, that indicates that you have just made a math error somewhere along the way.

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[@suyashschmidt6985]

Nice and concise... Thumbs up

[@Engineer4Free]

Thanks!

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saved mai life

[@Engineer4Free]

I gochu

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Thanks, love it!

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Thanks sooooo much

[@Engineer4Free]

You're welcome sooooo much ^_^

[@kharn105]

Dude, thank you so much!!

[@chezburger69420]

Early start of any activity should be always 1 ? where the early start of any other activity should be early finish of the previous activity +1? Please help?

[@Engineer4Free]

There is more than one way to network diagrams. I follow a consistent method in all of my videos on engineer4free.com/project-management , which stems from the way I draw and interpret Gantt charts. Basically, 0 represents the start of day one. 1 represents the end of day one, but also the start of day two. 2 represents the end of day two, but also the start of day three. If you trace the lines down on this Gantt chart www.engineer4free.com/4/how-to-draw-a-gantt-chart, you will see where the numbers that I use come from.

[@chezburger69420]

Thanks for yours clarification, can you help what should we follow in PMP?

[@ashberry2852]

thanks a lot

[@Engineer4Free]

you're welcome