CompTIA Project+ PK0-003

PERT/GANTT/CPM and Schedule Compression

by Steve Caseley

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What is Project Management

Project+ and how to prepare for the exam

Pre-Project Setup

Project Planning

Prepare Scope Statement

Create WBS and WBS Dictionary

Define Change Management Process

Develop Project Schedule and Resources and Roles

PERT/GANTT/CPM and Schedule Compression

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.

Communications Management Plan

Risk Management Plan

Quality Management Plan

Cost Management Plan

Procurement Management Plan

Transition and Project Management Plan

Human Resource Management

Project Governance

Project Tracking

Project Change Management

Project Risk Management

Project Quality Management

Project Delivery Management

Earned Value Management

Project Communication Management

Project Closure

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Steve Caseley

Steve Caseley

CBT Nuggets Trainer


Area Of Expertise:
Project Management, MS Project, Development Methodologies, Agile Development

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