Analyzing P6 Schedules Part 1

hello this is Bill pappan managing partner at construction science I've been using Primavera software almost since the very beginning the original program Primavera p3 was introduced in 1983 at the time I was using a different scheduling program the starting in 1987 I switched over exclusively to Primavera software so today we're going to look at a tool that it has evolved over the years originally it was called claim digger and at that time it was a standalone program into which you would import a Primavera p3 file when Oracle took over Primavera systems they incorporated claim digger into p6 now we're going to be looking at this version of the tool as it currently exists in version 18 of Primavera p6 and that's an important distinction as you're going to see in a few minutes it's no longer called claim digger they chose I suppose a less controversial name and now it's just schedule comparison but the concept is the same you take two files compare them to each other to see what exactly is different you're going to find out that there are pros and cons to this particular tool but I would say up front one of the biggest advantages of schedule comparison it is free once you buy Primavera p6 there are certainly other tools out there and in other videos I'll be discussing those as well but we might as well consider what can this free tool do for us schedule here and it's very simple what we're going to be doing is making a minor modification to this schedule I want you to watch me make the modification and then we will look at how schedule comparison tells us what changes have been made so this is the original version I'm going to copy it now I'm going to copy think about it I'm not going to leave anything out and then once I finish doing this well we'll call this the revised plan so I'll pick up over here and give it a slightly different name all right and you may have noticed that anytime you copy a p6 file that both the original and the copy will now be open so I'm going to reopen just the revised file so here's what I'm going to do I've got a relationship here between ruff and plumbing and roughen hvac if I click on it we can see that it's a finish to start relationship I'm going to overlap these activities by putting in a finish to finish relationship I'm also going to put in a 10-day lag now I have the scheduling mode turned on so the change has already taken effect and we can now see that these activities overlap between the plumbing and the HVAC so naturally that makes this different than the other schedule a couple of other things I want to point out that are very important for this particular analysis I am using project specific activity codes now this is the only one I really spent much time playing with I have this responsibility code so in a very simple fashion I gave each activity a responsibility code they keep in mind it's project specific I do not use EPS nor do I use global and that's just a rule something that you'll learn about in other videos that I've produced likewise the calendar is something we need to take a look at for a similar reason I never use global calendars I always use project specific I've got a seven-day calendar I've got a five-day calendar now it's also true I may have a global calendar with exactly the same names but Primavera stores them in different places in the database so it's not a conflict let's go ahead and close this out all right so I've made a change now we're going to compare the two files now in most recent versions of p6 in order to launch scheduled comparison you're actually opening up another program called visualizer schedule comparison runs inside visualizer so I'm going to go up to tools because that's what it is a tool you'll see that visualizer can be launched by itself now visualizer has two other tools which have to do with drawing the schedule as basically a Gantt chart but the one we're going to look at of course is schedule comparison particular button it's going to understand I want to go into schedule comparison and not one of the other tools I need to give my comparison a name so I'll say that it's the original versus the revised baseline if you've already run the comparison then you would be opening it up from an existing report so we're going to go down here to options and the first thing we have to do is pick these two schedules now what you're seeing here is a reflection of your enterprise project structure shown twice we have it on the left side and you have it on the right side now here's something that is extremely important because if you don't follow my instructions you're going to do this backwards and again I want you to understand I'm using version 18 everything I'm going to tell you right now gets flipped when you're using an older version of the program so in my version of p6 on the left side of the screen you are going to be selecting the new schedule what you consider to be the newer one now in my mind the revised schedule is the new schedule the original plan is the older version of that schedule and I think that's important because what if I go into the revised schedule and I add five activities if I reverse the comparison here Primavera is going to tell me that I deleted five activities because it's going to look at the old schedule as being the newer one so this is not just semantics it is very important to consider which one of these is the newer schedule and again in my version of p6 you select the newer schedule on the left side of the screen I have to expand these out every single time so here it is base - one without what I call the revised plan I'm gonna highlight that one and then on the right-hand side of the screen I do it all over again and this time I'll pick the other one the original plan now also I always thought it was curious because you can see here that you could also pick a baseline from the current schedule and call that the old schedule and that's what used to throw me off because it's always been on the right side of the screen so it's very easy to think that you are always picking the old schedule on the right hand side but if you're using that say version 16 or 15 anything like that anything older than that in fact you need to pick on the left side of the screen what you think is the old schedule so chances are on the right hand side you're not going to be using a baseline you'll be picking some other schedule now once you highlight them you click on add as you might have guessed I could go select two more schedules and add that to the comparison I would have one report that compares several schedules but this can be a fairly long report so I never really want to run more than one comparison of time so we're done selecting the schedules the next step is what sort of output would you like if you've never run this report before always choose HTML the first time you need to see it formatted because if you dump it into a spreadsheet which is what CSV would be you're not gonna notice the headers right away and there's quite a few of them in there so it's better to see how Primavera presents the data and then maybe dump it into a spreadsheet so I'm going to go back to HTML you would not want to grump it excuse me grouping by activity you're gonna have a line break after each activity it's gonna make for an extremely long report which I don't think gives you any benefit at all now under the Advanced Options we're going to leave all the boxes checked now eventually what I do if I'm only looking for logic changes you can probably see that some of these would be more useful comparisons than others let's say you had a thousand activities and you adjust the start date of the very first activity by one day Primavera is gonna tell you in this report that 999 activities all have new start dates new finish dates it's gonna be an extremely long report but it's a bit misleading because you didn't really change much it's just the ripple effect of changing a very early activity so quite frankly most of the time I don't even care to know that the dates have changed because it almost always is gonna show quite a few lines of data so if I was focusing on what I might call logic changes I would look at relationships right here and perhaps only leave that one checked and then we see we have a few others such as added and deleted activities that would be a real good one too also I would consider constraints so if you want to curve if you want to create the most concise report that you can to just focus on logic changes that's all you need added and deleted activities constraints and added and deleted relationships but again I'm gonna leave the whole thing checked so you get a sense of how big the report can be even though I think you would agree we changed very little about this schedule one relationship the last step here in the upper right hand corner is save and draw because this is a drawing program they do give you a slightly odd option here now I'm going to apologize because starting with version 18 the way that this is presented even on my screen the font is very small I can't really do much about it but when I print it I can try to blow everything up so it is a little difficult to read and this makes it hard to present even during my classes but that's at the very top you're gonna see that we have the two versions of the schedule listed they both would have the same data date but you may notice that here on the left hand side it's telling me about the old schedule finish on April 13th the new schedule finishing on April 6th they keep in mind we're overlapping a relationship which used to be finished to start so naturally we've picked up a little bit of time now as we start going through our comparison such as WBS code keep in mind this column here I'm going to call it basically the middle column the middle column is the new schedule what we decided is the new schedule the revised plan across from it is the old schedule now keep in mind the new schedule when you're looking at the WBS code the first part of any WBS code is the project ID so you're seeing SF offices base - one and then across from it you see SF offices base this is probably the first thing that throws people off Primavera is going to tell you that every activity in your schedule has a new WBS assignment and you're thinking well wait a minute all we did was copy the schedule yes but no two schedules in the same database have the same WBS codes that's never possible because the first part of the code is the project ID so all you would have to do is copy a file paste it and Primavera is going to tell you that you have all brand-new WBS codes that is a correct statement now to you you might see them as being exactly the same schedule even down to the dates perhaps but it is also correct to say that these are brand new WBS codes so you can imagine in a big schedule just getting through that part of the report might take you a few minutes to understand what's going on here why do I see hundreds of lines of information here listed now pretty soon you're going to see the calendar this also is going to be a little bit confusing did we change the calendar no I promise you we didn't change the calendar all we did was copy and paste the schedule but when you copy a schedule has project specific calendars those are brand new calendars they don't share the same calendars each one of them is an independent schedule they have their own project specific calendars now the names are identical and in fact the characteristics of the those two calendars are identical this is the one big weakness of schedule comparison Primavera only looks at the name of the calendar now you look at these two columns here and you're correct they have exactly the same name so Primavera in a way is telling us something that's not correct it's saying even the names have changed and that's not really true but here's another problem let's say in the copied schedule I open up that 5-day calendar and I add some new holidays if I leave the name of the calendar alone and I just continue calling it five-day when I look at this report I don't know what to think actually let's pretend I don't know who did this I'm looking at these two schedules for the first time all I see is that they both have the same name now sometimes when people change calendars thankfully they give it a slightly different name so seeing the brand new name would make me curious enough to go open up that schedule but the reality is this because Primavera is always going to tell you that they somehow have a different name even when the names are identical again because they're project-specific I don't know if I should think that they are identical or they're not the only way to satisfy yourself that the calendars are not different is to open up both schedules at the same time and cycle back and forth between the calendars in those two different schedules and just satisfy yourself that the hours per day that the non workdays and everything else are in fact identical do not rely upon this report to tell you whether the calendars are the same or if they are different I've even seen some times that the name of the calendar has changed when when I actually open up those two schedules and look at the characteristics there's nothing different about the calendars at all now as we go through again you're gonna start seeing new headers such as late start dates and this is kicking off a whole new category of just dates and you're gonna think I didn't do too much but midstream because I changed that relationship all future activities have new dates new late start dates new late finish dates you're gonna see early dates change early start and early finish we're gonna see that what we call the planned dates which are the same as the early dates as a practical matter but still primavera is going to tell me we have new planned dates start and finish and again all I ever did was change one relationship and then we finally get into just start and finish the ones that we should be relying upon the most and all of those have changed starting where I made the logic revision now did float change well absolutely and keep in mind float is a duration so that's going to start us off in this category called durations so naturally all the activities that follow the new logic have new float values they have total float values that are different they have free float values that are different and so as we go a little further we even start getting into the activity code assignments Wow look at this it's saying that all of the activity code assignments are different and you might be thinking what's going on there well once again like with the calendar when you copy the project because these are project specific activity codes the original ones are considered different than the new ones now the descriptions are identical the values are identical I had GC as a value for general contractor so it's telling me that I added a whole bunch of values we go through that and then it tells me likewise I deleted a whole bunch of activity code values but all we did was copy the project so I know when I go through this unless something really catches my eye that I see a value that's never existed before this is a bit of a false positive Primavera is correct in what is telling you but on the other hand I don't really care now as we get into ords the very bottom I want to start focusing on the fact that we change some logic and that's going to start right here now you have to think about this carefully but primavera is going to report my change four different ways I took a finish to start relationship and I changed it to finish to finish with a 10-day lag so here Primavera says we have a predecessor relationship that's been added so HVAC is the activity we're talking about and it has a new predecessor of rough-in plumbing and the lag is 80 now 80 is ours it's always reported in ours and I have an eight-hour day so it's going to show it up is 80 and there's the new relationship finish to finish and then right below that Primavera says well we have this predecessor relationship that's been deleted and once again we start talking about that predecessor being that activity we're focusing on is HVAC the predecessor plumbing and Primavera says we deleted that so keep in mind we change the relationship well let Primavera thieves is a deleted predecessor relationship and an added predecessor relationship likewise when we look at the successor so here we go and we look at plumbing and we're considering that plumbing now has a new successor relationship it's an 80-hour lag it is finish to finish and we see here the successor HVAC that's the new relationship on the successor side and then likewise Primavera tells us that we deleted the a relationship that plumbing down here used to have this finish to start relationship and it's been deleted that's also trim so this is where you have to be a little bit careful because it will seem like you've made a lot more changes than what you remember in most situations when you go in and you change a relationship you're gonna see that in fact it gets reported four times that it's an added and deleted predecessor relationship plus it's an added and deleted successor relationship so most of the time when I look at this report if I saw that I had 100 and changes to logic I would divide by four and assume that it's really more like 25 changes to logic now if we had gone in and just added a new relationship and we didn't delete anything it still gets reported twice as a new predecessor relationship and as a new successor relationship so the information is certainly very helpful but it might just cause you to think that apparently you've made a lot more changes than you remember it's not nearly that bad so again this is a nice report that we can start with before we before we spend any money on other tools to analyze these schedules but keep in mind that the particular weakness is on the calendar side I cannot trust this report to actually verify that the calendars are identical between these two schedules or if they are somehow different open them up and compare them side-by-side so in other lessons we will look at a few other tools and other ways that I like to compare schedules I hope you enjoyed this video and if you're interested in our classes you can find us at primavera scheduling com we offer videos as well as online classes with a live instructor and in-person classes at our training facility in Citrus Heights California which is near Sacramento thank you

Channel: Bill Pepoon

Views: 2,688

Rating: 5 out of 5

Keywords: Primavera P6, Primavera Scheduling, Schedule Comparison, Construction Science, Claim Digger

Id: MhsdRD-VOX4

Length: 23min 47sec (1427 seconds)

Published: Mon Oct 21 2019