Nieman,

I completely agree with your point about having a thought-out argument to back up any statements people make. Sometimes it can be useful to put forward something a bit controversial just to get people going and to see what develops. Also to say you don’t like some part of the methodology because you find it clumsy or difficult to use as that’s just an opinion which anyone is entitled to.

What is difficult to take is someone who pontificates to no purpose often venturing into the realms of the totally bizarre. In cases like this the culprit gets the mickey taken out of them, which can be great fun but may not be the best way to to deal with them. Unfortunately, I don’t have a clue as to what would be the way to go, any ideas?

Chris Oggham

I don’t mind new ideas, Vladimir, and we surely take the rise out of Charlie when he pontificates, but what I do not like is someone just saying that a generally accepted methodology is rubbish without giving us a thought-out argument to back it up!

I appreciate that language may be a problem, but believe that generally we make allowances for that (even for Clive’s spelling on occasion)

Thats more a statement than a subject may i suggest something like

’The Trans-Continental Migration of Scottish Planning Resources between 1988-2006’

The tensile strength of elastic, and the general concepts of elastic theory, applied to the nether garments of albino Inuits.

A subject dear to the heart of Anoon I belive

What topic should we digress with now??

Quite right!!!!!

In simple words,

Two types are:

--> Resource Driven activities
--> Non-Resource Driven Activities

Hammock is a rolled up task level and milestone is an achievement of activity or group of activity having ZERO DURATION.

So, in TOTO, U and James were trying to say d same thing in different terms.

Lets wait and watch, what ULY is going serve for all of us.

Cheers,

Hi Raviraj,
there are two major types of activities:
1) Type Duration means that its Duration is an initial information and does not depend on assigned resources,
2) Type Productivity means that its Quantity of work that can be measured in physical units OR manhours is an initial information and duration depends on quantity and productivity of assigned resources.
There are also milestones and hammocks (LOE activities) - additional types.

It is very interesting what will be suggested as an alternative to CPM. So let’s wait. Any discussion on scheduling methods is useful.

Regards,
Vladimir

Vladimir, James
Are you sure that we are still on topic?

I’ll join. It would be a nice feature. I don’t know regulations in other countries, but in Germany workers council doesn’t allow to store skill-related informations - the skills in P3e/P5 in a software which can be accessed by people apart from HR or the direct superiors.
Regards
Dieter

Vladimir,

I agree with you in principle, with regard to differing crews having differing productivity (we’re all different). However, do you find that there is such a significant difference that it’s actually worth planning to THAT level of detail? (ie. with differing output rates for the same activity type.)

James.

I agree with James, but probably didn’t explain as well!

Coal-face man-hours along with a efficiency factor, and actual required hours are used more in nuclear. Its hard to put a physical volume to many of the project stages in nuclear, as much of the work varies between sites and in different physical environments.

I think physical quantities are suited more to repetitive scheduling rather planning.

Oliver,
estimation of manhours for the concrete resource and estimations of resource productivity is the same. If there are different resources then manhours depend on their productivities and may be different for different crews.
Measuring and planning physical volumes is natural and flexible.

Vladimir

Hi Vladimir,

I just wonder whether we are going to split-hairs and start arguing about the same thing. Building a brick wall, for instance, might require 9 bricks (physical units) but who is going to build the wall: the man who is going to take 9 hours to do it. If he has done 5 hours, and still has 4 hours remaining, then he is 5/9 complete. Now, you could also define your progress by calculating the number of bricks he has laid....but this is a different story and a different thread that I was debating a couple of weeks ago.

To be correct in my terminology then, and in order to cover all industry types: Resource output per unit time [productivity rate] (be it manhours, metres or tons etc) is what determines the duration.

In my industry, the unit of measurement is usually man-hours. This is based on the fact that our physical output is entirely undefined in the conventional sense....for instance a single 3D model....where even "thinking time" has to be accounted for.

James.

James,
I don’t agree with your statement "that manhours is usually the fundamental unit by which your resource requirements/duration will be defined."
The usual fundamental unit is the quantity of work to be done in the physical units (we call it volume of work and measure in meters, tons, cubic meters, pieces, etc.). Knowing assigned resource productivities and quantities we will be able to calculate activity duration. Knowing necessary duration we can calculate necessary productivity of assigned resources and thus to decide about necessary resource types and quantities.
Regards,
Vladimir

I think the start point of any alternative has to be to identify what is wrong with what exists at the moment

As the old adage goes " if it aint broke dont mend it"

Why dont you list out whats wrong with CPM

Then what you would like to change

That way maybe we can all provide some help.

Ulysses,

I really don’t know why you feel such hatred toward the CPM methodology. It is a perfectly good process if you understand the way it works….and can compile a properly resourced and linked schedule.

Your earlier post, with regard to using differential calculus and statistical distribution of the rate-of-change of progress is, actually, very interesting. However, you are forgetting one major element in all of the calculations that you are likely to perform: and that is the fact that you are trying to forecast the future, based on the statistical extrapolation of historical data. This methodology is equally as flawed and all that will happen is that you will become bogged-down in mathematical formulae that will prove to be no more accurate than the CPM that is being applied to a well-constructed and maintained programme. The so-called “flaw” is that:

1) The fundamental activity data (manhours etc.) are based on an estimate. We all know that estimates are likely to be +/- 20% (which itself is an estimate)….so I already have introduced a compounded error [making an estimate of the fundamental activity data, and then estimating that the accuracy of that data is +/-20%.]. You will still get an exact result, but that result is likely to be no more accurate than some of the simpler methodologies.

2) Previous performance is not an indicator of future performance (although there is a probability factor in that it might be). However, as soon as you introduce a probability factor, you must accept that there is a range of results. Therefore, your forecasts will lie between Y1-Y2. For the extrapolation to be valid, you must have enough historical data points to ensure validity…..and by the time you have enough historical data to be statistically valid, conditions have changed once again.

One of the big problems is that humans are totally irrational and are looking for certainty where certainty does not exist. When they themselves have to compile an estimate, they will always claim that “it’s only an estimate”. However, when someone else gives them a number, they expect it to be adhered to and written in concrete. Our expectations change in accordance with our emotional involvement with the project. If we hear that a $2 billion project went 5% over-budget, then we’d still applaud the accuracy of the estimate. However, if we were charged $1.05 for a bar of chocolate that was advertised as costing $1.00, then we’d be furious. Anyway, I digress…….

James.

the thing is, There is no other tool!

Can you even differentiate between LoB and CPM?

CPM is method of identifying the critical path.

LoB is a methed of presenting a schedule to show increased/decreased efficiency?

Clive,
if I understood it correctly people use Tilos together with Primavera and MS Project.
Spider Project was created for project resource management, it is too complicated for Line of Balance approach to scheduling. But Line of Balance project presentation is very useful and is included as one of the standard ways to present project schedules. Besides you can create and use any metrics, not only meters or stores, like stage 1, stage2, ... So it used not only for roads and high rise construction.
I hope that one day you will use Spider Project.
Regards,
Vladimir

This approach does not help when resources, finances, supplies are limited. It may be considered as an alternative to CPM when computers are not available.

Line of balance is just another way to present project schedule like Gantt Chart and Network Diagram. In Spider Project Line of Balance (Linear Diagram) is one of the standard project presentations.

CPM is a proven method to create project schedules when resources are unlimited.
With limited resources you shall calculate resource critical path (or critical chain).
What is the problem?