00:00:00 - With the project schedule behind us we move on to the next element
00:00:04 - of our project planning road map which is 2.5
00:00:08 - PERT/GANTT/CPM. When we were discussing the project schedule
00:00:13 - I said I was going to go through some of the theory behind how
00:00:16 - the project schedule is developed. This nugget is going to focus
00:00:19 - on the theory and the theory is called PERT/GANTT/CPM and I'll
00:00:24 - explain what all of those acronyms mean in just a few moments.
00:00:27 - And in this nugget we're also going to discuss 2.6 which is Schedule
00:00:33 - Compression. Now I have greatly condensed the formal definition
00:00:38 - from CompTIA. Let me read you the formal definition from CompTIA.
00:00:42 - 2.5 given a desired deliverable apply the appropriate tool and/or
00:00:49 - method to produce the appropriate outcome with subsections for
00:00:53 - PERT, GANTT, and CPM and 2.6 given a scenario interpret the results
00:01:00 - using the following tools and/or methods GERT,
00:01:06 - CPM network diagram, ADM, PDM, CDM,
00:01:10 - and CCM.
00:01:13 - Again I've consolidated all of those formal definitions and I
00:01:16 - think I have very appropriately consolidated them into
00:01:20 - discussion on the pertinent most relevant components of the academic
00:01:25 - theory behind scheduled development which is the PERT, THE GANTT,
00:01:29 - and the CPM with a specific focus at the tail end of this nugget
00:01:33 - on techniques we need to apply for schedule compression. So let's
00:01:38 - roll up our sleeves and get into this nugget. In a little more
00:01:41 - detail this nugget is going to focus on, as I said, CPM/GANTT/
00:01:45 - PERT. So what is CPM? It's a critical path method. It identifies
00:01:54 - the schedule
00:01:57 - sorry, had a spelling challenge there for a moment, it identifies
00:02:05 - the schedule using a technique called the critical path method
00:02:09 - or as we just expressed,
00:02:12 - CPM. We're also going to review a diagramming technique
00:02:23 - and produce what's called a GANTT chart where in fact we're not
00:02:27 - actually going to produce the GANTT chart, we're going to look
00:02:30 - at GANTT charts that's going to be drawn for us by our scheduling
00:02:33 - software. This is not an artistic drawing course but the GANTT
00:02:39 - chart is a specific diagramming process that we often use as
00:02:45 - project managers to represent
00:02:49 - the schedule.
00:02:53 - And my expectation is any of you taking this series are probably
00:02:57 - very familiar with the GANTT chart itself.
00:02:59 - We're going to look at a technique called PERT and this is to
00:03:03 - help develop
00:03:07 - realistic estimates.
00:03:14 - And finally we're going to look at two techniques for schedule
00:03:18 - compression. So you're halfway through your project and your
00:03:21 - project is running late or you're halfway through the project
00:03:25 - and the business sponsor comes to you and says "We need to do
00:03:28 - this a little faster. How can we speed up the project? How can
00:03:33 - we get it back on track? How can we speed it up?" and we're going
00:03:36 - to look at fast tracking
00:03:40 - and we're going to look at crashing. But
00:03:49 - before we get into the real meat of this nugget I need to slow
00:03:52 - us down and spend a moment or two talking about some more alphabet
00:03:56 - soup as if rolling out the acronyms for CPM, GANTT, PERT weren't
00:04:02 - enough I need to describe four more acronyms that we had in the
00:04:07 - long definition from CompTIA itself and that's PDM Precedence
00:04:13 - Diagramming Method, ADM Arrow Diagramming Method, CDM Conditional
00:04:17 - Diagramming Method,
00:04:21 - and finally CCM Critical Chain Method.
00:04:27 - It is important that you're aware of all of these acronyms and
00:04:32 - that you're aware of what these acronyms mean.
00:04:35 - PDM we're going to explore in this nugget is Precedence Diagramming
00:04:40 - Method. In a PDM we use boxes
00:04:45 - to represent our activities or our tasks in our project
00:04:51 - and we connect the tasks using arrows. And that's the most common
00:04:58 - method used although my experiences on the Project Plus exam
00:05:03 - itself you may get theory questions about the ADM, the CDM,
00:05:10 - or to some extent the CCM. Any practical questions you're going
00:05:16 - to get should be, most likely will be based on the PDM, the Precedence
00:05:22 - Diagramming Method, because it is by far the most commonly used
00:05:26 - diagramming method and as we get in looking at the Critical Chain
00:05:30 - Method and Critical Path Management you will see why the PDM
00:05:36 - is the most commonly used and literally it's because it gives
00:05:39 - us more real estate to do our Critical Chain Method.
00:05:43 - The Arrow Diagramming Method is just the opposite
00:05:50 - we use connectors, which are the boxes, but our activities are
00:05:54 - on the arrows.
00:06:00 - So the boxes are simply connectors
00:06:06 - and literally provide nothing but graphical representation and
00:06:12 - all of the information is stored on the arrow. The benefit of
00:06:16 - the PDM over the ADM as I said should become relevant as we go
00:06:21 - through the rest of this nugget and focus on the Critical Chain
00:06:25 - Method. I'm jumping ahead a little bit I realize in my alphabet
00:06:29 - soup. The Critical Chain Method is
00:06:33 - the method we're going to explore later in this nugget to calculate
00:06:38 - the critical path
00:06:42 - so in terms of alphabet soup recognition all you need to do is
00:06:46 - associate CCM, Critical Chain Method, with Critical Path and
00:06:51 - Critical Path Analysis and you'll do just fine. And then lastly
00:06:55 - in our alphabet soup is the CDM, the Conditional Diagramming
00:06:59 - Method. This is a way to diagram activities that loop or repeated
00:07:04 - throughout our project and it is a way to diagram activities
00:07:08 - that are not in sequential order. It's not a diagramming technique
00:07:12 - that we will use a lot or that you will probably use ever.
00:07:18 - For your Project Plus again you need to be aware of what Conditional
00:07:22 - Diagramming Method is and it is for repeating,
00:07:29 - looping processes
00:07:33 - and with knowing the definition of CDM you'll be fine. You will
00:07:38 - explore PDM throughout this nugget, we will use PDM to calculate
00:07:44 - or to use the Critical Chain Method which will calculate our
00:07:48 - critical path and these two you need to know the theory,
00:07:54 - the definition only.
00:07:57 - So with the alphabet soup behind us let's roll up our sleeves
00:08:01 - and start focusing on CCM, the Critical Chain Method, and let's
00:08:07 - focus on finding out what our project's critical path really
00:08:10 - is. A significant part of this nugget is focused on critical
00:08:16 - path or as we just explored the official term is CCM, the Critical
00:08:21 - Chaining Method, but most project managers will refer to this
00:08:24 - as the critical path. I wanted to spend a little minute with
00:08:29 - you on the definition of critical path because I find that the
00:08:33 - terminology critical path
00:08:36 - I believe is a little misappropriately named. Critical path is
00:08:41 - defined because it defines the project's end date and obviously
00:08:46 - knowing the project's end date is critical
00:08:51 - to us as a project manager and as part of determining the project
00:08:55 - end date it determines all of the critical tasks which are on
00:09:00 - the path
00:09:03 - to the end date.
00:09:07 - That's' the project management definition of critical path it
00:09:11 - identifies the tasks which determine the project's end date.
00:09:17 - Any changes to any of those tasks on the critical path is going
00:09:23 - to impact the project's end date and hence why it's called critical.
00:09:29 - So if we have a task 15
00:09:33 - on our critical path it has an estimate of four days but when
00:09:39 - it comes time to complete that task our resource takes six days
00:09:45 - to complete the task that is going to push
00:09:49 - the end date out by two days.
00:09:54 - There is a direct on-to-one relationship between any change to
00:10:00 - any task that's on the critical path, i.e. the critical tasks,
00:10:06 - a one-to-one relationship between any change on any task that
00:10:10 - is on the critical path and the project's end date. In this example
00:10:15 - the task took two days longer than expected, it's going to change
00:10:19 - our end date by two days if we got lucky, and the task was completed
00:10:24 - in two days less, it's going to shorten our task, our project
00:10:30 - by two days.
00:10:33 - As a result critical path management is very much a focus for
00:10:39 - project management. Anything that happens on these critical path
00:10:43 - tasks is going to impact our project end date. Now going back
00:10:48 - to why I think it's a little misappropriately named. A lot of
00:10:53 - new project managers when they first hear the term critical path
00:10:59 - or critical task they think of the important
00:11:04 - tasks, the big
00:11:09 - impact tasks,
00:11:14 - the ones that make them worry.
00:11:22 - So how's that the important task, the big impact task, the task
00:11:27 - that make me worry different than the task on the critical path?
00:11:31 - Well the critical path is all schedule-based.
00:11:36 - The important task may be validating
00:11:42 - a proof of concept.
00:11:47 - Once the proof of concept is validated
00:11:50 - boy, that was an important task-now my proof of concept is done,
00:11:56 - now I have confidence that my technical solution is going to
00:11:58 - be a success.
00:12:00 - It's an important task, we certainly need to validate that POC
00:12:05 - before we're going to have any confidence in our solution, but
00:12:08 - let's face it that validating of the POC took five days
00:12:13 - and it was done early in the project.
00:12:17 - As a matter of fact it may have been done so early in the project
00:12:21 - that we didn't have our full team on board, etc, etc and if the
00:12:27 - POC took a day longer it may or may not impact our project's
00:12:31 - end date. The big impact task, the task that made me worry the
00:12:34 - same thing they may or may not have any relationship to determining
00:12:40 - the project's end date. And one of the best examples of
00:12:46 - PM critical path tasks versus the important big impact tasks
00:12:52 - that I've ever had described to me was the rollout the development
00:12:59 - of a theme park.
00:13:02 - And in this theme park they were going to have wild animals
00:13:16 - on display. And in order for these wild animals to be displayed
00:13:20 - in their natural
00:13:22 - habitat they needed to grow
00:13:27 - grass. And because this grass had to be well established so
00:13:35 - that when these wild animals started running on it and grazing
00:13:39 - on it, that the grass was going to survive,
00:13:43 - the critical path task for this project literally was growing
00:13:47 - up the grass and it was a two-year
00:13:52 - task. So for two years after the grass was planted
00:14:01 - literally nothing was happening on the project besides "watching
00:14:08 - the grass grow." I'm sure they were watering it, I'm sure they
00:14:12 - were fertilizing it, I'm sure they were nurturing it along the
00:14:16 - way because they wanted the grass to be in good shape but literally
00:14:20 - the critical path, the task
00:14:24 - that determined the project's end date, when the front doors
00:14:29 - to that park opened was the growing of grass. Limited resources,
00:14:39 - limited cost,
00:14:43 - etc. etc but the amount of time it took for that grass to grow
00:14:48 - literally determined the project's end date. And that's the point
00:14:53 - I want to drive home from a project management viewpoint critical
00:14:57 - path or the task that determined the project's end date are not
00:15:02 - the important big impact, make me worry tasks. Yes, as a PM we
00:15:08 - certainly need to worry about these things but again
00:15:13 - PM Critical Path management Project Plus Certification exam passing
00:15:18 - we need to distinguish that critical path, CCM method, is
00:15:24 - based on identifying
00:15:28 - the critical task that determine the project's end date. Now
00:15:32 - let's explore how all that happens.
00:15:35 - So the Critical Chain Method and again more commonly referred
00:15:39 - to as the critical path is dependent on six things. We need the
00:15:45 - WBS done.
00:15:47 - We have already discussed creating of the WBS in this series;
00:15:51 - we need to understand all of the dependencies between the tasks
00:15:55 - done already discussed in this nugget series; and we need to
00:16:01 - have estimates for all of the tasks in the project schedule done.
00:16:08 - So a lot of the work for Critical Chain Method, critical path
00:16:11 - creation, we've already discussed in this nugget series. We're
00:16:15 - going to focus now on the next three elements of the Critical
00:16:19 - Chain Method which is something called the forward pass,
00:16:24 - the backward pass, and from these
00:16:28 - we're going to determine the float or the slack and knowing which
00:16:33 - tasks have float or slack allows us to determine
00:16:39 - the critical path tasks
00:16:42 - which as a result determines the project
00:16:47 - end date.
00:16:50 - I'm not going to try to explain the theory behind these approaches,
00:16:56 - I'm going to show you these approaches in action. So
00:17:01 - let's put this into action using Precedence Diagramming Method
00:17:04 - that we discussed earlier. We're going to create the dependency
00:17:07 - diagram and that dependency diagram is going to show all of the
00:17:12 - information that we've already discussed in previous nuggets.
00:17:16 - We have the WBS, tasks A, B, C, D, and
00:17:23 - E so that's our complete WBS for our project, we have the dependencies,
00:17:28 - that A must finish before B can start -a Finish-Start relationship
00:17:35 - A also must finish before D can start another Finish-Start relationship
00:17:42 - B must finish before C can start
00:17:45 - and we have a dual relationship for E, both C and
00:17:52 - D must finish before E can start, and we have our estimates A
00:17:58 - has an estimate of five units for that sake of simplicity let's
00:18:01 - call those days B has an estimate of three days, C has an estimate
00:18:06 - of two days, D has an estimate of four, and E has an estimate
00:18:11 - of four. And using all of that we'll now start to apply the CCM,
00:18:16 - the Critical Chaining Method, to determine our critical path
00:18:20 - and to do that we're going to start to apply these concepts of
00:18:25 - early-start-early-finish, late-start-late-finish
00:18:30 - and we get those concepts from forward pass
00:18:37 - and the forward pass is going to determine our early start
00:18:43 - and our early finish
00:18:46 - and our backward pass
00:18:50 - is going to determine our late start and our late finish.
00:18:57 - So we simply start to plug this into our diagram. We start at
00:19:02 - the first task in the project which is A. Its earliest possible
00:19:06 - start is zero.
00:19:09 - And because it is five days of duration it's going to complete
00:19:13 - at the end of day 5.
00:19:16 - Now that A is finished these two tasks can kick off. Let's focus
00:19:21 - on B in this path first. The earliest possible start for B is
00:19:27 - going to be bright and early, first thing in the morning on day
00:19:30 - 6, has a total effort of three days, so it's going to finish
00:19:36 - on day 9.
00:19:41 - With B done C can kick off so again C is going to kick off bright
00:19:44 - and early on morning 10, has an estimate of two days, so it's
00:19:50 - going to complete at the end of day 12.
00:19:55 - Now when can E kick off?
00:19:58 - Well it may be able to kick off first thing in the morning on
00:20:02 - the 13th but until we complete all of the other paths -and in
00:20:07 - this case we only have one I've developed a very simplistic diagram
00:20:12 - for us but we cannot calculate the early start and early finish
00:20:16 - on any task that has multiple predecessors until we know what
00:20:21 - the early-start-early-finish for all the predecessors are. So
00:20:24 - we do the same thing we go down this path now. What is the earliest
00:20:28 - possible start for D? Assuming we have resource independence,
00:20:32 - i.e. D is being worked out by a different resource than B, again
00:20:37 - D can start off bright and early in the morning on the 6th, it's
00:20:42 - going to take 1-0 days of effort, so no it can complete on day
00:20:47 - 10. Now that tells us what is the earliest possible date that
00:20:53 - E-4 can start and you may say "Well E can start on 10, that's
00:20:58 - the earliest possible date, it could either start on 10 or 12"
00:21:03 - but 10 is not the right answer. The earliest it can start is
00:21:08 - the 12th because it cannot start before either,
00:21:14 - it cannot start before both C and
00:21:18 - D are complete. The reason we had to wait for this path to be
00:21:22 - completed it could have been calculated to complete on the 14th
00:21:25 - or the 18th or the 28th day
00:21:28 - the earliest possible day that you can start is actually the
00:21:33 - 13th, bright and early on the morning of the 13th and it has
00:21:38 - a duration of 17 days.
00:21:42 - And now we start our backward pass backward pass is going to work
00:21:46 - in this direction, no surprise. Because this is the determination
00:21:50 - of our project our late start and late finish are going to be
00:21:54 - the identical so we copy them down
00:21:58 - and we say "Okay, let's work backwards." What is the latest
00:22:05 - possible date that this one can finish and still allow that guy
00:22:09 - to start on the 13th? It's the 12th,
00:22:13 - has the duration of 2, so it's the 10th. We work backwards. What's
00:22:19 - the latest possible date this one can finish to still allow this
00:22:23 - guy to start on the 10th? It's going to be the 9th,
00:22:27 - has the duration of 3, so it becomes the 6th.
00:22:31 - Again we can't calculate A yet because it has multiple successors,
00:22:36 - same relationship works in reverse, forward pass its predecessors,
00:22:42 - backwards pass its successors so again we work backwards. What's
00:22:48 - the latest possible date this one can finish and still allow
00:22:52 - this guy to start on the 13th? This is where we begin to see
00:22:55 - some differences. The latest possible date for this guy is also
00:22:59 - the 12th. If D finishes on the 12th E can still start on the
00:23:05 - 13th because at that point both C and D are complete.
00:23:10 - D has a duration of 4 so D has a
00:23:15 - late start of the 8th.
00:23:19 - Now again we work this one backwards, what is the latest possible
00:23:24 - date this guy can finish and still allow these to exist? It's
00:23:28 - going to have to be the 5th and because it has the duration of
00:23:32 - 5 it's going to be the zero. So
00:23:36 - I want to take just a moment and recap what we did. First we
00:23:39 - did our forward pass one path through the project at a time,
00:23:45 - starting at zero, duration of 5, this task finishes on 5, the
00:23:50 - earliest possible date this guy can start is the 6th, duration
00:23:54 - of 3, finishes on the 9th, earliest possible date we can start
00:23:58 - this one is bright and early the next morning which is the 10th,
00:24:02 - duration of 2, finishes on the 12th and at this point because
00:24:07 - there are multiples we can't determine what its date is yet,
00:24:11 - we have to complete the other paths. A finishes late day the
00:24:16 - 5th, D can start bright and early the morning of the 6th, has
00:24:21 - a duration of 4, completes on the 10th. Now
00:24:26 - with these two facts in mind D finishes early finish on the 10th
00:24:33 - C early finishes on the 12th so the earliest possible date E
00:24:37 - can start is bright and early the morning of the 13th and completes
00:24:41 - on the 17th
00:24:44 - that's forward pass. Where I think it gets a little more challenging
00:24:49 - to understand your first, your second time through this is how
00:24:53 - we calculated these numbers specifically on our backward pass.
00:25:00 - I think these numbers are I hope fairly self evident. If this
00:25:05 - task finishes on the 13th
00:25:08 - what is the latest possible date this guy could start and still
00:25:13 - allow him to start on the 13th? It's going to be last thing at
00:25:17 - night on the 12th, duration of 2 gives me the 10th. What's the
00:25:23 - latest possible date this guy can finish and
00:25:27 - allow this guy to start on the 10th? It's going to be the 9th
00:25:30 - and so on backwards.
00:25:33 - The uniqueness is right here D
00:25:37 - again what's the last possible date that D can finish and still
00:25:44 - allow E to start on the 13th? Same as the discussion up there,
00:25:49 - if D completes on the 12th E can start on the 13th and with D
00:25:56 - being a duration of 4 the latest possible date that D can start
00:26:02 - is the 8th
00:26:05 - which is considerably different than the 5th.
00:26:09 - And that's the last part of our discussion for the Critical Chaining
00:26:13 - Method is determining the float
00:26:17 - or the slack.
00:26:20 - And most textbooks use the terms float or slack synonymously.
00:26:24 - The float or slack is the difference between the late finish
00:26:29 - and the early finish or the late start and the early start. It
00:26:34 - doesn't matter whether you work from the start or the finish,
00:26:39 - the float or slack for D is two days,
00:26:46 - the float or slack for E is zero, the float or slack for C 12
00:26:53 - minus 12, 10 minus 10 is zero; similarly
00:26:58 - for B there is no float or slack and there is no float or slack
00:27:03 - for A, B, C, or E but
00:27:08 - there is float or slack for D of two days.
00:27:13 - Therefore my critical path is
00:27:17 - A to B to C to E is my critical path
00:27:27 - and that's what the Critical Chaining Method allows us to calculate. So
00:27:32 - with the critical path calculated I want to take us back to the
00:27:35 - CCM, the Critical Chain Method, and talk about what you need
00:27:39 - to know to pass your certification exam.
00:27:43 - Obviously you need to know how to create the WBS, the dependencies,
00:27:47 - and the estimates. We had previous nuggets focused on those aspects.
00:27:53 - In terms of what do you need to know with the forward pass, the
00:27:56 - backward pass, and the float and slack the answer is yes,
00:28:01 - you need to know all of the above you need to know how to take
00:28:05 - your box,
00:28:06 - early-start-early-finish, late-start-late-finish,
00:28:16 - you need to know how to take and determine what the next early-start-early-finish,
00:28:24 - late-start-late-finish is going to be based on the estimates.
00:28:31 - You absolutely need to know how to do all of that and you need
00:28:36 - to be prepared to do that as part of your Project Plus Certification
00:28:42 - exam. My expectation is you will be given a diagram, probably
00:28:47 - not a lot more complicated and probably very similar and I'm
00:28:52 - not saying it's going to be identical to this but it's going
00:28:54 - to be probably no more complicated than five or six tasks with
00:29:00 - probably no more than two or three possible paths through it.
00:29:05 - Some of the numbers will be given 5, 3, 2, 4 and all of the early
00:29:13 - start finishes, late starts finishes will be given and you will
00:29:19 - be asked to determine what is the estimate for that task or more
00:29:24 - appropriately it will give you the estimate for that task and
00:29:27 - it will calculate what is or the question will ask you "What
00:29:31 - is the appropriate early finish for the uncalculated
00:29:37 - task?" or "what is the late start for the uncalculated task?" So
00:29:43 - absolutely you need to understand the mechanics of doing the
00:29:46 - forward pass, the backward pass, and with that you need to understand
00:29:51 - the mechanics of doing the float or slack calculation which is
00:29:54 - pretty simple you subtract the difference between either the
00:29:58 - early-start-late-start or the early-finish-late finish and you
00:30:06 - need to know that any tasks which has a none-zero float or slack
00:30:13 - is non-critical and any task that have a zero float or slack
00:30:18 - are critical. So again given all of this it may say which is
00:30:24 - the critical path for the project, is it this one, and it would
00:30:28 - list them off A.
00:30:31 - B, C, and E or it is a D and
00:30:36 - E. Be prepared to do
00:30:40 - the math
00:30:42 - and the math is as simple as adding, subtracting
00:30:47 - very rudimentary numbers but be prepared to do some calculations
00:30:51 - on critical path and be prepared to do some analysis on critical
00:30:58 - path techniques which is what we're going to discuss next. So
00:31:03 - with the critical path known we need to focus on critical path
00:31:07 - management. And just to refresh we had A,
00:31:12 - B, C, D, and E,
00:31:23 - D had float/slack of 2,
00:31:28 - these guys were all zeroes, so our critical path again to reiterate
00:31:34 - was A, B, D, and
00:31:36 - E. So knowing the critical path tasks
00:31:40 - as a project manager we need to know which tasks are on our critical
00:31:46 - path and Steve's terminology we need to manage every task on
00:31:52 - that critical path list like a hawk, we need to watch them
00:31:58 - like the hawk soaring in the sky looking for food,
00:32:03 - we as project managers need to be soaring over our project looking
00:32:07 - for issues,
00:32:10 - deviations, problems,
00:32:17 - anything that could impact any of our critical path tasks, we
00:32:22 - need to manage them like the hawk, we need to watch carefully
00:32:26 - for any issues,
00:32:28 - deviations, problems because if we have one day
00:32:32 - slippage on any one of the 45, 80 tasks on that critical path,
00:32:41 - if we have a single day slippage on any one of A,
00:32:46 - B, C, or E that's going to make our end date
00:32:51 - slip by one day or if we have a two-day slippage etc. etc.
00:32:58 - Know your critical path tasks and manage them like a hawk; know
00:33:03 - your near critical path tasks and then manage them carefully.
00:33:09 - So what is a near critical path task? I've told you what a critical
00:33:14 - path task is they have the float/slack of zero.
00:33:19 - What is a near critical path task? They are the guys with the
00:33:23 - float or slack near
00:33:26 - zero. What is near zero? Well use your imagination I don't mean
00:33:33 - to say that sarcastically or facetiously but use your imagination.
00:33:37 - If I have a task that has a float or slack of half a day
00:33:45 - that's pretty there and close to being a critical path task because
00:33:48 - if I have a deviation of no more than half a day or of half a
00:33:54 - day it's going to impact my critical path. Same thing a day if
00:34:00 - it only has a float or slack of a day it's near critical path,
00:34:05 - we need to manage it very carefully. If more than a day
00:34:10 - change happens
00:34:12 - then it is going to become a critical path task and it's going
00:34:16 - to start to impact my schedule. If my float or slack is 15 days
00:34:23 - a lot of nasty things can happen to that task with a 15-day float
00:34:28 - or slack, I would say 15 days is nowhere near critical path,
00:34:35 - I would say a half a day or a day is near critical path, I would
00:34:41 - say two days yes. When I say "use your imagination"
00:34:46 - I say use your imagination because if this is a
00:34:50 - two-week project
00:34:53 - anything in this range is certainly going to impact.
00:34:58 - If it is a longer project you may need to consider
00:35:04 - 15 days probably would be never near critical path but maybe
00:35:08 - even a five-day task is worthy of some attention.
00:35:13 - How much time do you have to manage the near critical path task
00:35:18 - carefully? It's probably going to be a large contributor for
00:35:22 - whether near is less than one day or less than five days or whatever
00:35:27 - the case is going to be.
00:35:30 - Now knowing your critical path tasks, manage them like a hawk,
00:35:34 - know your near critical path task, manage them carefully. I
00:35:39 - don't want to lull you into a total sense of security with the
00:35:43 - non-critical path tasks that have substantial float or slack
00:35:47 - of 15 days because they're probably never going to impact your
00:35:51 - end date but let's face it if you have a task that was supposed
00:35:56 - to take five days and it took an additional
00:36:01 - 14 and I'm deliberately picking 14 because it keeps you from
00:36:06 - becoming critical path this has now become a 19-day task.
00:36:11 - If you're paying for your resources your budget/cost
00:36:17 - has increased by
00:36:20 - 300%. So manage the rest of the tasks for budget,
00:36:27 - they're not going to impact your schedule, but that task that
00:36:31 - increased by 14 days has effectively increased my cost for that
00:36:37 - task by 300%, it's going to impact my budget. Now we haven't
00:36:41 - discussed budget management yet in this nugget series but we
00:36:44 - will be soon so again I don't want to lull you into this false
00:36:47 - sense of security, you do need to be aware about the rest of
00:36:51 - the tasks on your project and manage them for all aspects besides
00:36:57 - critical path management, project end date management.
00:37:04 - And that concludes our discussion on CCM, critical path management.
00:37:08 - With that behind us we need to go back to the preliminary alphabet
00:37:11 - soup that we had of critical path, CPM, GANTT, PERT and spend
00:37:17 - a few moments discussing the next alphabet soup which is the
00:37:21 - GANTT chart. Now GANTT doesn't describe any acronyms, GANTT does
00:37:26 - not spell it to anyone, in fact GANTT is the last name of the
00:37:30 - gentleman who first developed this diagramming technique and
00:37:35 - therefore it has been named after his last name which is Gantt.
00:37:40 - What do we use GANTT charts for as project managers? Primarily
00:37:44 - it provides a calendar view of the project schedule. A lot of
00:37:49 - people refer to it as a bar chart.
00:37:53 - It allows us to take the tasks,
00:37:59 - have a calendar week 1, week 2, week 3 and see when the physical
00:38:06 - schedule is going to happen based on our project's calendar.
00:38:11 - The most common application of the GANTT chart is that calendar
00:38:15 - view of the schedule. Other very common usages of the GANTT format
00:38:21 - is to produce a milestone chart. The only difference between
00:38:25 - a calendar view traditional GANTT schedule and a milestone chart
00:38:30 - is instead of showing tasks on the GANTT chart on the calendar
00:38:34 - view we're showing milestones.
00:38:42 - And remembering what milestones are they're key points in our
00:38:48 - project that is of interest to management so again we're providing
00:38:52 - a calendar view that says on week 2 milestone completes and on
00:38:56 - week 7 milestone completes. Similar strategy for the summary
00:39:01 - chart instead of showing tasks, detailed tasks, instead of showing
00:39:05 - milestones we show the high level summary
00:39:09 - but the same basic information. So let's look at a better artistic
00:39:15 - rendition of a GANTT chart besides my hand scratching. And
00:39:20 - just to give you a slightly better representation of what a GANTT
00:39:23 - chart should look like besides my scratching here is a GANTT
00:39:27 - chart that was produced by a piece of management software. We
00:39:31 - have our detailed tasks showing over here in the left, we have
00:39:35 - the calendar view of the weeks in my project, and we have the
00:39:40 - duration of the various tasks. So task 1 starts on a Wednesday
00:39:44 - and finishes on a Friday, task 2 starts on the following Monday
00:39:48 - and so on. Most scheduling software is going to allow me to manage
00:39:53 - the degree of granularity I have in my calendar view, here I'm
00:39:57 - showing it by a day. If I was getting into a milestone GANTT
00:40:01 - chart or a summary GANTT chart I would scale my calendar and
00:40:05 - probably have the low level view as a week, my higher level view
00:40:09 - as months, or if it was a long project I could even come down
00:40:12 - into lower level view of months and a higher level view of years. But
00:40:18 - this is a graphical representation of my project schedule typically
00:40:23 - referred to as a bar chart or giving credit to the gentleman
00:40:27 - who first developed this diagramming technique, a GANTT chart. And
00:40:33 - our final stop on our high level acronym discussion is PERT.
00:40:39 - PERT officially is called the Program Evaluation and Review Technique.
00:40:45 - It wouldn't hurt to memorize what Program Evaluation and Review
00:40:49 - Technique is but I would suggest for your Project Plus exam it
00:40:54 - will be referred to as PERT and understanding the mechanics of
00:40:58 - PERT is probably all you need to know. And what are the mechanics
00:41:02 - of PERT? PERT gives us an optimized
00:41:09 - estimate. But in order to give us the optimized estimate we need
00:41:15 - to have three estimates.
00:41:19 - So for each task
00:41:22 - we need to develop what is the optimistic,
00:41:28 - the most likely,
00:41:32 - and the pessimistic.
00:41:36 - So for every task in our WBS that we estimate
00:41:41 - we have to put on three hats we put on an "if the world were
00:41:45 - perfect and nothing bad ever happened on my project I could do
00:41:50 - this task in
00:41:52 - seven days."
00:41:58 - Then we put on a "Well the world isn't perfect
00:42:03 - so therefore it's most likely going to take me about 10 days
00:42:09 - to complete this task." And then we put on our sad face hat,
00:42:15 - our pessimistic hat and say "Not only is the world not perfect,
00:42:18 - it's not even likely, it is a horrible place to live in and all
00:42:24 - kinds of evil things are going to happen to my project, to my
00:42:27 - work on this particular work, and it's going to take me 14 days
00:42:31 - to get the task done."
00:42:34 - So wearing our three hats perfect world, most likely world, and
00:42:38 - pessimistic world with the 14
00:42:41 - we have all the information we need to calculate our PERT or
00:42:47 - our optimized estimate and to do that we have our PERT formula
00:42:52 - which is the optimistic plus the pessimistic plus four times
00:42:56 - the most likely over six and more times than not it's written
00:43:00 - in a much shorter form than that, PERT
00:43:04 - equals optimistic plus four times the likely plus the pessimistic
00:43:12 - all over six and if we see that in action PERT for this example
00:43:19 - equals the optimistic is 7 plus four times the most likely is
00:43:25 - 40 plus the pessimistic which is 14,
00:43:31 - we divide all of that by 6 and to avoid you having to listen
00:43:36 - to me do all my mental math the answer is going to be 10.
00:43:43 - Now in this case it turned out to be exactly the same as our
00:43:47 - most likely,
00:43:49 - that's simply because my contrived numbers worked out that way,
00:43:54 - but if we take the optimistic,
00:43:57 - four times the most likely plus the pessimistic, give it the
00:44:02 - weighted average of 6, we will come up with what I would describe
00:44:07 - as an optimized estimate.
00:44:09 - PERT estimation is a highly recommended approach to coming up
00:44:14 - with optimized estimates, more realistic estimates for your project.
00:44:20 - Your estimation and therefore your project schedule will be far
00:44:24 - more realistic if we apply the PERT approach.
00:44:29 - The problem with doing the PERT approach is it takes a lot of
00:44:34 - work to come up with three estimates. It takes a lot of work
00:44:37 - to come up with a single estimate for a task. If we have to come
00:44:41 - up with three estimates for every task and we have 200 tasks
00:44:45 - in our project that's a lot of work.
00:44:49 - Don't let the amount of work required to come up with the optimistic,
00:44:53 - pessimistic, realistic deter
00:44:56 - you from using the PERT approach because you will get much better
00:45:00 - estimating as a result of applying the PERT technique. And again
00:45:05 - be prepared for your exam to do some calculations. They will
00:45:10 - give you the optimistic, the most likely the pessimistic,
00:45:13 - they won't give you the formula, you're going to have to memorize
00:45:16 - the formula but given these three estimates what would be the
00:45:21 - most realistic estimate or what would be the PERT estimate this
00:45:26 - task, you simply do the math on the piece of paper that they're
00:45:30 - going to provide for you and pick the right answer from their
00:45:33 - multiple choice. Be prepared again to do the math
00:45:40 - and memorize
00:45:44 - the formula. And if you have concerns about memorizing the formula
00:45:48 - memorize the formula, the second you sit down in the exam write
00:45:53 - that formula down on your scrap piece of paper so as you start
00:45:56 - to take the exam you don't have to worry about forgetting the
00:45:58 - formula. And the final topic for this nugget is schedule compression.
00:46:06 - You're halfway through the project and you need to do it faster.
00:46:11 - You're running late
00:46:15 - and the customer says "What can we do to bring this back on track?
00:46:19 - Being late is not an option" or they simply ask
00:46:23 - for it sooner,
00:46:28 - or any other of a thousand reasons the business is going to come
00:46:31 - to you and say "Steve you need to do this a little earlier. I'm
00:46:36 - not happy with your current forecasted end date. Can you possibly
00:46:41 - compress the schedule and deliver the project to me sooner than
00:46:46 - the current forecast?"
00:46:48 - The only two options we have is to do a thing called crashing
00:46:52 - or do a thing called fast tracking. But before we discuss our
00:46:57 - two options I want to take you back to our discussion on critical
00:47:00 - path remembering that the critical talks define the end date.
00:47:12 - So as we're exploring our options for crashing or for fast tracking
00:47:18 - only explore the schedule compression options for the critical
00:47:23 - tasks that are on the critical path the float/slack
00:47:28 - equals zero. You can do all of the crashing and fast tracking
00:47:32 - that you want on a task that has a float
00:47:37 - of 15
00:47:39 - and you're not going to impact the project's end date at all.
00:47:44 - Only focus your schedule compression on the critical path tasks.
00:47:49 - So what are our two techniques? Crashing basically we add
00:47:55 - resources to our critical tasks
00:48:00 - to try
00:48:02 - to do the task faster.
00:48:08 - So we have a task that has a 40-hour
00:48:15 - estimate. As we discussed of resource availability and focusing
00:48:24 - our estimating on effort versus duration we know if we take a
00:48:28 - 40-hour task, put two resources
00:48:33 - on it we're going to do it twice as fast half the time.
00:48:40 - So ideally we always want to have a single resource on a single
00:48:44 - task because it gives us the accountability and the ownership
00:48:48 - that we've discussed already but if we're challenged with schedule
00:48:52 - compression there may be tasks where crashing, adding resources
00:48:58 - to try to do it faster will work.
00:49:03 - There may be tasks that adding resources will allow us to crash
00:49:08 - the schedule and make it faster, may.
00:49:12 - You need to apply considerable thought process to which tasks
00:49:18 - are appropriate for crashing and which tasks will get into trouble
00:49:22 - with crashing.
00:49:24 - Now when I talk about adding resources in this instance I talked
00:49:28 - about adding equivalent work
00:49:32 - resources. Remembering that resources are human, material, or
00:49:41 - equipment maybe we can crash a task by adding material
00:49:49 - or equipment resources
00:49:53 - to our human resources.
00:49:57 - So what do I mean? We still have the task of 40 hours that's
00:50:02 - going to take John
00:50:05 - to do the task. Maybe if we go out and buy 15 extra large coffees
00:50:12 - and give it to John he can work faster because we're going to
00:50:17 - have him so hyped on caffeine that he's going to do the task
00:50:20 - a little bit faster.
00:50:22 - Not a good example but it's a possibility but let's talk about
00:50:27 - a better example. If we add equipment maybe John is constrained
00:50:37 - by the speed
00:50:40 - of his compiles. So
00:50:44 - if we could buy John a new hopped up on-steroids PC that's going
00:50:50 - to reduce his compile time by 50%
00:50:55 - by adding equipment
00:50:58 - to the task the new hopped up PC we can in fact reduce the estimate
00:51:05 - from 40 to 30 hours because the time spent waiting for compiles
00:51:11 - is going to be reduced by 50%. Or if we add more material, if
00:51:15 - we add extra whatever to the task it may work faster. So when
00:51:20 - we're looking at crashing
00:51:23 - can we add more human resources and taking advantage of the fact
00:51:27 - that effort with more resources takes less duration or can we
00:51:33 - add material or equipment resources that may allow the task to
00:51:37 - complete faster?
00:51:40 - Fast tracking means working
00:51:45 - more tasks
00:51:49 - in parallel. The
00:51:53 - plan originally was A complete,
00:51:57 - B starts, C starts, and D starts.
00:52:02 - Re-look at our B and
00:52:06 - C through mandatory remember those mandatory versus discretionary
00:52:11 - dependencies? Is B to C a true mandatory? Maybe we can re-work
00:52:18 - the project schedule and make all of B, C, and
00:52:22 - D all simply dependent upon A rather than making C dependent
00:52:27 - on B. Look at where you can unserialize
00:52:31 - the project schedule
00:52:34 - and do more tasks in parallel. Again there are risks with doing
00:52:38 - it in parallel.
00:52:40 - During our dependency definition we focused on only identifying
00:52:44 - the true mandatory dependencies,
00:52:48 - there is risk with saying "Well three months ago I thought that
00:52:52 - C was totally dependent on B, what makes me think I'm any smarter
00:52:57 - now? What makes me think that C is any less likely to be dependent
00:53:01 - upon B now?"
00:53:03 - Think it through but if we fast track again A and C was on the
00:53:09 - critical path, this will in fact reduce our schedule end date.
00:53:15 - Schedule compression only on critical path tasks, we have the
00:53:19 - option of crashing which is adding resources, human equipment
00:53:23 - and material or fast tracking which is parallelolizing
00:53:27 - the project schedule to a greater extent than originally planned. To
00:53:33 - summarize this alphabet soup nugget CPM, GANTT, and PERT we focused
00:53:39 - on the critical path, identifying
00:53:44 - the tasks
00:53:47 - which define
00:53:51 - the end date.
00:53:54 - To do that we needed to know the WBS,
00:53:58 - we needed to know the estimate, we needed to know the dependencies
00:54:04 - all discussed in the previous nugget and to do that we added
00:54:08 - the concept of a forward pass,
00:54:13 - the backward pass,
00:54:15 - and then the calculation of the float and the slack.
00:54:23 - Anything with a float or slack of zero was on our critical path
00:54:28 - and therefore defined our project's end date; anything with a
00:54:32 - float or slack of non-zero we're not on the critical path and
00:54:36 - therefore did not define the project's end date.
00:54:41 - We took the information from the critical path method itself
00:54:44 - and used that when we are challenged to schedule a compression
00:54:48 - and we looked at the technique called crashing,
00:54:53 - the adding of resources,
00:54:59 - or we looked at the concept of fast tracking
00:55:04 - which was parallel
00:55:07 - to the project to a larger extent. And we also looked at a diagramming
00:55:16 - method created by Mr. Gantt which gave us a calendar view
00:55:25 - of the WBS
00:55:28 - or the milestones
00:55:30 - or the summary and we looked at this PERT approach to give us
00:55:35 - realistic estimates
00:55:41 - where PERT consists of the formula for we take the optimistic
00:55:46 - plus four times the most likely plus the pessimistic
00:55:51 - divided all by 6 to effectively give us a weighted average which
00:55:56 - should give us a much more realistic for each and every task
00:55:59 - in our project WBS. This
00:56:02 - concludes our nugget on CPM, GANTT, PERT, and schedule compression.
00:56:07 - I hope this module has been informative for you and thank you
00:56:10 - very much for viewing.