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Re: Conservation Laws

Dorina Grossu 1216242600|%e %b %Y, %H:%M %Z|agohover
in discussion General / Discussions » Conservation Laws

Tom,
I read your article but certain events occurred that changed totally my view on conservation laws. Due to these events, I have started to read about brain functionality, and more importantly about CSF (Cerebrospinal fluid) that has a major role in our brain. While we try to elaborate more on conservation laws, our own nature does not conserve anything, on a contrary there is a continuous exchange of information resulting in residue elimination. Links: http://www.csuchico.edu/~pmccaffrey/syllabi/CMSD%20320/362unit3.html

I am more inclined to treat TOC in a similar way with human brain because we are the "creators" of any management system that currently exists.

As I remember from my school years (many years ago), conservation laws occurred as a start point and theories were applicable by making tones of assumptions.

While searching for conservation laws I found this article: http://www.nd.edu/~ehagedor/papers/papineau.pdf

Re: Conservation Laws

PhilipOakley 1215556428|%e %b %Y, %H:%M %Z|agohover
in discussion General / Discussions » Conservation Laws

There are no conservation laws for human systems. Rather the opposite, Time is the use it or loose it proposition, and then we create the 'false god' of some sort of token of exchange to try and stand in for value and trust and fairness.

The Fair trade - Free trade arguments are one example, as is union - bosses relationships that want most people to have above-average wages, etc.

The only certainties in life are running out of time, and someone devaluing your material 'wealth' (death & taxes ;-)

Doesn't stop us trying to create a stability with oneself on top of the rolling log.

Re: What is a dollar day?

PhilipOakley 1215555878|%e %b %Y, %H:%M %Z|agohover
in discussion General / Discussions » What is a dollar day?

This presumes that money has value, rather than time. In practice neither time nor money is conserved, in fact time is clearly a use it or loose it proposition. It is the appearance of the conserved value of money that keeps many economies going.

Re: What is everyone's goal?

PatWilson 1214892128|%e %b %Y, %H:%M %Z|agohover
in discussion General / Discussions » What is everyone's goal?

FYI…
One TOC book that you may of heard of, but from my perspective gives one of the best perspectives on both a troubled culture and the transformation to a flourishing (meeting organization and personal goals) is GREAT BOSS DEAD BOSS by Ray Immelman. The direct TOC references are almost non existent, but Ray mentioned at a conference that his logic for the fiction story was in large part worked out with Thinking Process tools. The main concepts are of our natural inclination to align/associate oursleves and our values with tribes and managements role in the organization to understand these forces and their role to optimize the organizational performance.

Re: What is everyone's goal?

Tom Kemp 1214779630|%e %b %Y, %H:%M %Z|agohover
in discussion General / Discussions » What is everyone's goal?

I haven't read 'Built to Last' but I understand (from a talk by Eli Goldratt last year) that it believes the companies it mentions have in common that they have built a "culture". I've been too vague in what I mean by 'choice' but that is deliberate until I have thought about it a lot more. It just seemed reasonable to search for a common, underlying concept of what a "goal" might be. I suspect a "culture" emerges as a secondary attribute of an organization as it successfully moves towards its goal. The more successful a company is, the longer it will persist, the more it will believe what it is doing is correct, the more it will retain what it believes are its successful characteristics. Such organizations are 'fit' in the sense of evolution and will therefore appear to have teleological characteristics. I want to be careful to distinguish these from the underlying evolutionary processes in which I'm most interested.

Re: What is a dollar day?

Tom Kemp 1214779019|%e %b %Y, %H:%M %Z|agohover
in discussion General / Discussions » What is a dollar day?

That's a really interesting question. If I own a dollar right now then all dollar-days representing the future of that dollar might as well have my name on them. However, I might plan to spend my dollar one week from today. I'm promising to Alice that I shall buy a cup of tea from her in 7 days time. We could replace my name by Alice's on all dollar-days which represent the dollar's future starting a week from today. Alice might be able to persuade a bank that she indeed will own those dollar-days in order to get a loan, for example. The entire economy is built on the premise that dollars will change hands and that different people will therefore own the various dollar-days available.

A lost dollar-day is a dollar-day I should have had but, for some reason, didn't. This was the case where Alice didn't make my tea in time and I had to pay her two days later than she expected. I owned the two dollar-days which she wanted. She "lost" them. In answer to your question, the only dollar-day I can actually lose today is the one which represents that dollar today. I can't lose tomorrow's dollar-day until tomorrow. However, I might predictively lose tomorrow's dollar day. For example, if I do a job for you and want 10 dollars for it then I expect to get paid when I finish the job. I expect the job to take 5 days. However, let's say I started the job two days ago but have already run into trouble with my supplier. I estimate at the moment I will take another 6 days. That means I expect to be 3 days late. I am therefore predicting that I shall lose 30 dollar-days even though I'm not owed any money yet. However, I haven't really lost those dollar-days yet (ie they aren't in anyone's possession yet, even yours) and if I sort out the problems with my supplier I might even manage to finish a day early and claim 10 dollar-days which I wasn't expecting.

Hope that sheds some light on at least my understanding of what a dollar-day is.

Re: Systems within systems

Tom Kemp 1214777844|%e %b %Y, %H:%M %Z|agohover
in discussion General / Discussions » Systems within systems

We've had a few replies to this one and I don't claim to understand them all fully. This wiki is an interesting one because (hopefully) it attracts people from many different disciplines all of which have their own specialist language and, in particular, may use the same term as another discipline to mean something different by it. I think (like Pat) the only way to overcome the possible confusions which this will lead to is for everyone to define what they mean by a specialist term. Some of the terms used already are 'system', 'subsystem', 'supersystem', 'cognitive', 'energy', 'adaptive', 'action', 'effect'. And by 'define' I mean really define using simple terms which we can all agree on. I can define 'kinetic energy' as half the mass of an object multiplied by the square of its velocity, assuming that 'mass' and 'velocity' are simpler, more universally understood concepts. If we don't do this then we'll go round in circles and come to simplistic conclusions. It would also be really useful to give real examples of what we are talking about to help everyone reach a mutual understanding of the problems and possible solutions being discussed.

In that spirit, I suppose it's up to me to define 'system'. I use Goldratt's definition of 'a set of dependencies between entities (such as tasks or logical propositions)'. My background is in computer science so I model a system in this sense as a 'graph'. Graph theory (see the wikipedia entry) is a useful mathematical tool for describing such systems. It doesn't care what the entities are; it's the dependencies between them which count. A 'subsystem' is therefore just a subset of those dependencies. Because graph theory doesn't worry about what the entities or dependencies mean then it's not much good for discussing the details of real systems. For example, graph theory allows us to look at any arbitrary subset of dependencies in a system but in real life I'm guessing such a subsystem doesn't always make much sense. For example, I can look at an organization composed of departments. These are "natural" subsystems of the whole system. But I could also look at a small part of a department's work which is a valid subsystem of a subsystem. However, can this small part have its own goal? It probably doesn't if we haven't bothered to give explicit measures to that part. However, we do measure each department and that department will have a goal (such as 'be the best department in the organization') or is it because we measure the department it has a goal? It certainly looks like measurements and goals are intimately related.

I am woefully ill-educated with respect to psychology so I apologize for my poorly-thought-out remarks during the first post about the goals of individuals. I know I personally have a goal and I'm sure many others do. I'm just interested, as a novice, about how those personal goals co-exist within a system of people where the system itself is said to have a goal.

I mentioned the notion of 'choice' in another post and how I think it is every system's ultimate goal. Does that notion help here? I haven't defined what I mean by 'choice' and I don't think I can yet but maybe it would make sense to follow through a system and watch how 'choice' is handled throughout the system. If a person is trying to maximise his or her choice then when two people work together on something do they have to compromise their personal choice (I know how TOC hates a compromise!) in order to achieve that shared goal. In a very large system such as an industrial organization trying to make more money now and in the future (or more 'choice' now and in the future) how does that affect the levels of individual choice. Sorry, I'm meandering but there's something floating around my head about goals, choice, entropy and conservation which I'm going to need some time to work through…

Re: Conservation Laws

Tom Kemp 1214775011|%e %b %Y, %H:%M %Z|agohover
in discussion General / Discussions » Conservation Laws

I have also been considering an analogy to entropy. I like your thought about TOC aiming to reduce 'entropy'. One can imagine some management philosophies reducing the entropy (however we define it) for subsystems (see another posting about sub- and supersystems) while simultaneously increasing it for others. I have to think about this and see how this fits in with the notion of TOC attempting to increase the 'choice' available to systems. Sorry, I think very slowly so will come back to this when I have something more interesting to say!

Re: How long should a project buffer be?

Tom Kemp 1214766547|%e %b %Y, %H:%M %Z|agohover
in discussion General / Discussions » How long should a project buffer be?

I actually have very little practical experience in 'project' environments. My posting was a response to the numbers quoted in the book, 'Critical Chain', and the online, 'Insights'. It was just a warning that there is an inherent assumption that the sum of the ideal median times assumed for tasks could be safely added up to give the median time for the critical chain as a whole. In fact, as the diagram shows (but I haven't bothered to prove it mathematically), this is definitely not the case. I agree with every point you make and that we are dealing with reality. I just hoped that someone may have done some empirical studies in a particular industry (such as software development) to show the true skew of the times it takes to execute common tasks.

The safety required for a critical chain should be the additional time needed from the median time to finish up to, say, a time where we are 90% sure of finishing. Are we just lucky that we can add about half the sum of the medians of the tasks to the length of the critical chain to get about the right amount of safety or, as I'm starting to think, we could have a lot less safety and still hit a due date? I'm just questioning the rule of thumb and wonder how the intuition that came up with it justifies that rule.

Re: Systems within systems

PatWilson 1214755301|%e %b %Y, %H:%M %Z|agohover
in discussion General / Discussions » Systems within systems

This is a great new site! Thanks (It looks like Tom Kemp) setting this up and somehow getting me invited!

Another interesting subject that I can't help to chime in on.

A lot fo terms used in the preceding posts that it is important to level set everyone on (on how I interpret them).

example terms I read:
System
Subsystem
"Actual" system
"Cognitive" system

True, evey system is also a subsystem of a greater system. But I think the part of a subsystem that is real is only the parts that are actions and effects. We call entities that imply cognitive influences of a system, or sometimes the "nonphysical" systems, or sometimes "intangible" systems. Examples of entities that are intangible are goals, needs, policies (a few more but you get the point). There are only two distinct entities which are physical or tangible and they are of course actions and effects. Effects could be called a state or a condition. Some of the teachings coming from Goldratt say that the only real entities of the system are the physical entities, and therefore the only thing that can change "reality"are actions. Interesting.

Now, getting back to the terminology. I often hear references to physical systems or intangible systems as if they're two seperatge sybsystems in and of themselves. I would venture to say that this is not true at all. While there exist purely physical subsystems (meaning systems with no cognitive/rational influences - e.g. water erosion of a mountain, the orbits of the planets arount the sun - they have cause and effects but occur regardless and independent of reason stemming from thought) But I declare every system invlolving humans don't have seperate subsystems of rational entities but rather an intangible dimension of the subsystem. In other words, our goals cannot be achieved without an action occuring to change a physical state (to cause an effect), no intelligent action can take place without an underlying rationale.

So in conclusion I would say that a rational system leading to cause and effects, even a subsystem, could not be described fully without describing the both the physical and nonphysical entities of the system since the effect could not exist without both. That is therefore why I believe it is more true when describing a "cognitive" or rational system, when referring to the physical entities or the intangible entities, to call them either the tangible or intangible dimension of the subsystem rather than as seperate subsystems. And lastly, there can be no meaning to a system without an asscociated rational, which would mean totally physical systems lacking any cognitive influence have no meaning. And likewise the flipside of that is that the intangible dimension of the system that has intangible elements is what gives those systems meaning.

Thanks again everyone for a very intersting forum!

Pat

Re: Conservation Laws

PatWilson 1214753225|%e %b %Y, %H:%M %Z|agohover
in discussion General / Discussions » Conservation Laws

Good subject!

As I was reading your post I thought about a related concept of symmetry and that is entropy. If a system's entropy is minimum when it is most ordered, and maximimum when it is least ordered or smoothed, or in equilibrium, then relating that to what you call cognitive systems, I would think that a cognitive system is most ordered when goals are defned and people are achieving their goals to the highest extent.

Now, the question is: Is the goal of Goldratt's TOC to reduce entropy in humam systems?

For reference here is one interpretation of entrop
y from Wikipedia:

Statistical mechanics explains entropy as the amount of uncertainty (or "mixedupness" in the phrase of Gibbs) which remains about a system, after its observable macroscopic properties have been taken into account. For a given set of macroscopic variables, like temperature and volume, the entropy measures the degree to which the probability of the system is spread out over different possible quantum states. The more states available to the system with higher probability, the greater the entropy. More specifically, entropy is a logarithmic measure of the density of states. In essence, the most general interpretation of entropy is as a measure of our uncertainty about a system. The equilibrium state of a system maximizes the entropy because we have lost all information about the initial conditions except for the conserved variables; maximizing the entropy maximizes our ignorance about the details of the system.[12] This uncertainty is not of the everyday subjective kind, but rather the uncertainty inherent to the experimental method and interpretative model.

Re: What is a dollar day?

kevinrutherford 1214488632|%e %b %Y, %H:%M %Z|agohover
in discussion General / Discussions » What is a dollar day?

Are dollar-days interchangeable? Does a dollar-day today mean the same as a dollar-day next week?

Or to put it another way — is it worse to lose a dollar-day today than it would be to lose it tomorrow?

Re: Systems within systems

Dorina Grossu 1214427660|%e %b %Y, %H:%M %Z|agohover
in discussion General / Discussions » Systems within systems

This is an interesting view from a theoretical perspective.
Daily individual interactions dislocate an inconsistent energy therefore, system would have different energy outcomes depending on input. System's goal can be converted into energy levels but if we need to apply formulas, it will become complex and unrealistic. It can be done as a theoretical model (not sure if it does not exist already) by considering personality types and different energy levels.

Goals as achievements can be considered 100% that we know it is not attainable but from there we can deduct probably the chances of success.

Equation at balance: ∆Energy of the system+ ∆Energy of surroundings=0

Re: How long should a project buffer be?

dagny 1214388797|%e %b %Y, %H:%M %Z|agohover
in discussion General / Discussions » How long should a project buffer be?

Using CC tasks to size the PB should be just the starting point for buffer size. Prudent risk analysis, including checking for likelihood of task iterations could cause a considerable change in buffer size.

Re: How long should a project buffer be?

Productivity Guy 1214342492|%e %b %Y, %H:%M %Z|agohover
in discussion General / Discussions » How long should a project buffer be?

Three small pieces:

1. Although my own experience supports Eli's rule of thumb, it's really a rough approximation, dependent on the experience of the estimator with the task involved, coupled with the tolerance of the customer (which is the only real brake on infinitely extending task / project durations). Once people start to get their heads around the CC concepts, their starting estimates are no longer reliably uninformed (i.e. the complex adaptive estimating system has changed - and one would expect that estimate to shorter than when they estimated without the CC insight.)
2. It may be that the the whole measurement thing needs consideration, because there isn't really a minimum time for any particular task - there are, perhaps only two really tangible numbers:
   1. The estimated time - accurate or inaccurate, ambitious or conservative (this is a forecast of how long it should take in the cognitive system)
   2. The actual time taken - in a specific instance or across multiple instances (this can be very precise, but doesn't indicate, repliably, how long it could actually take, because of the impact of the cognitive system on the actual one).
3. One would assume that the proportion of safety allocated should take the level of unpredictability within the environment into consideration, particularly if there is a small number of tasks with wildly assymetrical time probabilities?

Re: Systems within systems

Productivity Guy 1214341444|%e %b %Y, %H:%M %Z|agohover
in discussion General / Discussions » Systems within systems

Hi Tom - 'thought I'd have a play with you on this one…

I think that there is a distinction between the actual system (what is happening) and the cognitive system (what we reckon is happening). From this point of view, I'm not sure that any actual system has a goal - actual systems may well evolve (for want of a better term) in a certain direction, but even that is up for debate, given the title of your posting.

If you agree with me here, you may also agree that your assertion that "every system has a goal" may well apply to a cognitive system rather than an actual system.

I'm not discounting that the sort of sytems we're talking about are complex adaptive system , but think that although the actual system influences and is influenced by the intelligent response of (for the most part) people, there are, once again two (sub) systems at play: the actual subsystem and the cognitive subsystem. The cognitive subsystem would have at least one goal (one or more of various types, perhaps), but I'm not sure that actual subsystem has a goal, merely because the cognitive subsystem has one.

Do you think that it's worth exploring this - or defining more specifically what we're referring to by "system" and "goal"?

Re: What is everyone's goal?

bryanmcn 1214305348|%e %b %Y, %H:%M %Z|agohover
in discussion General / Discussions » What is everyone's goal?

Have you read "Built to Last"? It is one of the few books that Eli talks about besides his own. In it, Collins explains that the Built to Last Companies have something else as a goal besides making money. Goldratt hinted that this may be the case in the Last Chapter of "The Goal. Johnah says; "Making money is not my goal and I don't think its yours". Can a company verbalize a goal like a one person can ?

Re: How long should a project buffer be?

cching 1214156383|%e %b %Y, %H:%M %Z|agohover
in discussion General / Discussions » How long should a project buffer be?

How long? This long.

Clarke (testing)

How long should a project buffer be?

Tom Kemp 1214084339|%e %b %Y, %H:%M %Z|agohover
in discussion General / Discussions » How long should a project buffer be?

The classic way of calculating the length of the project buffer for a critical chain is to throw away half the assumed saftey quoted in each task and then put the remaining half at the end of the chain as the project buffer. Has anyone done any research into how much safety really is included in the quoted time for each task in particular industries? Anyway, how do we know that half the length of the trimmed critical chain is appropriate as a project buffer?

The mathematics of combining the skewed probablity distributions of each task in the critical chain are not that simple. The resulting distribution curve for the entire critical chain has an extremely long tail and a very low "body". If we look at the median of this curve then it is way to the right of the sum of the medians of the individual critical chain tasks. So just adding up the (trimmed) estimated task times does not give us anywhere near the correct answer for the duration of the project which gives us a 50-50 chance of finishing it on time, ie the project buffer should start much later than we are told. The fact that projects run using critical chain project management finish on time therefore implies that there is still too much safety in those projects.

On the other hand, if we look at the duration which gives us a 90% probability of finishing the project on time then we find it is way to the left of the the sum of the 90% times for each task. So the overall project is relatively much less risky than any individual task.

The result is that the level of safely required for the entire critical chain (ie the project buffer) is much less (proportionately) than is required for any individual project, which justifies Goldratt's claim that we can throw away much of the assumed saftey in each task. How long should the project buffer be? Unless we know the real distribution curves for the tasks involved then we cannot know and this is why we need evidence from particular industries in order to build some heuristics.

What is a dollar day?

Tom Kemp 1214081001|%e %b %Y, %H:%M %Z|agohover
in discussion General / Discussions » What is a dollar day?

I was with a client who said, "So, I can spend a dollar to buy something; I can spend a day doing something; how can I spend a dollar-day?".

This started me thinking about what exactly is a dollar-day. I think it's simply a day in the life of a dollar bill. Imagine this drawn as a little green rectangle. Then a week in the life of that dollar bill is 7 such rectangles, which we can arrange in a line. Now, on each day the bill belongs to someone. We can mark each rectangle with that person's name. If I own the bill on Monday and Tuesday then those two rectangles show 'Tom'. If I then buy a cup of tea for a dollar from Alice then Wednesday's rectangle shows 'Alice'. In fact, Alice saves the dollar and so the remaining rectangles (as far in the future as we care to look) all contain her name.

The more rectangles which have my name on (ie the longer I possess the dollar bill), the more choice I have. My choice is the same every day: spend the dollar or save the dollar. We are calling each of these little rectangles a "dollar-day". So the more dollar-days I possess the more choice I have in my life. I could say to Alice, "You can have the dollar bill today or at the end of the week.". What will she do? She is guaranteed to take the money earlier rather than later. Why is it so important to have the money as soon as possible? It's often instructive to think of extreme cases. In one case we give a baby a dollar bill and in the other we give a dollar to a person on their death bed. In the first case we are being much more generous to the person: the baby will grow up and could choose any day during his or life to spend the dollar.

What if Alice takes a couple of days to make my cup of tea (yes, I'll get very cold tea). I wanted to pay her on Wednesday but she now has to wait until Friday to get her money. She has missed possession of two dollar-days. The dollar still exists but the dollar-days belonged to me during a time when she should have had them. From Alice's point of view these are lost throughput dollar-days. I'm annoyed because I don't have the tea when I was promised it. You might think I would be happy to have possession of two more dollar-days than I was expecting. However, my choice has been denied: I wanted to spend my dollar on Wednesday; in fact, I didn't want those two dollar-days.

The reason for lining up dollar-days as a sequence of rectangles is that we can reason about sets of dollar-days geometrically. For example, the month-long history of ten dollars would be ten sequences of small rectangles stacked on top of each other. This is a large rectangle with dimensions 10 (dollars) by 30 (days). I find it useful to teach the arithmetic of dollar-days by manipulating such large rectangles.

So, I told the client, you can't spend a dollar-day; you can either own it or not own it.