Tagged Posts: Constraints
Shared bookmarks for del.icio.us user Synesthesia on 2006-03-14
Clarke Ching points to Network Rail’s document Consultation On Capacity Study For East Coast Main Line [PDF, 546kb], which documents a Theory Of Constraints approach to managing resource capacity – in this case on a strategic rail route.
Clarke quotes the introduction which sets out the way the methodology was adapted, within the body of the document there is more on how they assessed capacity at the various constraints along the route.
Another quote relates to how the first list of probable constraints was found:
The starting point of the analysis was the selection of the potential constraints to be considered. A draft list of locations to be studied was produced using Network Rail’s detailed working knowledge of the East Coast Main Line. One approach has been to discuss potential issues with the Network Rail Timing Specialists who have a timetabling responsibility for the area of interest. Commonly they have been asked ‘which location / locations are likely to prove problematic?’. One of the tenets of the ThOC is that the over-riding constraints will be widely recognized. The locations selected for analysis have been discussed with each of their operators and they have each indicated their agreement. It is reassuring in this respect that the locations studied to date feature prominently in the responses of consultees to the applications.
Although the document is 85 pages long, I think it is worth at least a skim as an example of application of the approach to a new field.
What seems especially valuable to me in this example is the evidence that even in the complex multi-company and government environment of the UK railways, the use of a logical approach such as the Theory Of Constraints was capable of gaining support from the parties involved.
It is this aspect which, I think, points to the wider usefulness of the example as a learning tool which may point to new areas where application of constraints thinking could be useful. For example I can see possible application in the media production industry where application of digital networked techniques to complex supply chains will inevitably lead to contention over common pieces of infrastructure.
I’ve started looking at one of the pieces of pre-work for the strategy course.
Summary notes of the problem are here.
The challenge is to make the system profitable, with a strong steer to focus on increasing revenue. This post contains my first thoughts about a solution.
My first thought was to look at the constraints in the system – how could the management increase Throughput without increasing Operating Expense or Investment?
It would appear that there are different constraints at different times of the year.
In the peak summer season the trams run near capacity at all times, suggesting that there is excess demand, and the constraint is in the contribution received for each passenger carried. An easy strategy to try here would be to increase the fare price and thus the contribution per passenger carried. The case asserts that for the affluent tourists the current fare is insignificant, so the market should bear this.
In the early and late weeks there is excess capacity on the trams that run, suggesting that the market is the constraint. The passengers are mostly locals, and are price-sensitive. A 20% price rise has created a drop of 40% in passenger numbers in the early weeks of the season. If this is reversible then reducing prices in the off-peak part of the season should be offset by increased passenger numbers.
So strategy 1 is seasonally-adjusted pricing, with a reduction in the off-peak weeks and an increase during peak periods. There is a policy constraint that requires the average fare across the season to remain at $2.
Assuming that the price-sensitive drop in passenger numbers is reversible, then initial analysis suggests that reducing the price to $1.66 (i.e. a reduction to prices from 20 years ago) in weeks 1-13 and 25-32, combined with a price rise to $2.50 in weeks 17,18, 22-24 and to $2.60 in weeks 19-21 (the increases calculated to meet the average price constraint) will move the company to profitability, even accounting for the loss of state subsidy, wage increases and loan repayments.
To sense-check this would need some detailed figures on capacity which are not available in the study.
Ming links to this article about research into “Hypertasking” which suggests that although frantic multi-tasking (with the help of phones, IM, email, feeds, etc., etc., etc.) has the appearance of productivity the reality is of significantly reduced performance on the individual cognitive tasks. This is not the first study to suggest that multi-tasking makes you perform less well – for example this, this and this.
In the comments to Ming’s post there are a range of views expressed but two themes emerge:
* using the tools available today to _filter_ incoming information and tasks, allowing you to concentrate on the important things
* there is indeed a very sharp limit to the power of conscious processing to handle multiple tasks (Miller’s [bliki]SevenPlusOrMinusTwo[/bliki]) but the unconscious mind is capable of many many simultaneous activities.
From my own subjective experience I would suggest that one reason why having too many things to do “simultaneously” hits productivity is because it ignores the way the mind transfers things into unconscious processing.
The trick seems to be to concentrate on one thing sufficiently long that you build up a whole set of pathways relating to it, then “put it down” and move on to something else – the unconscious will still be working away. Do this and you will be surprised how often the answer “just appears” a few hours or days later.
Time-slicing too finely in the conscious domain seems to have the effect that no topic creates enough energy to engage the unconscious learning circuits, so I’m left relying on the distractable power of the conscious alone.
It would be interesting to explore the neuroscience of this a bit further…
From a [bliki]TheoryOfConstraints[/bliki] perspective it would appear that conscious attention is the constraint, so useful questions to consider might be:
* How do I get the most out of my conscious processing power?
* What else do I have to change to allow my conscious attention to work at its best?
* How can I find other ways of processing information (e.g. exploiting my unconscious mind)?
“A Guide to Implementing the Theory of Constraints (TOC)”:http://www.dbrmfg.co.nz/Preface.htm [via "Frank Patrick":http://www.focusedperformance.com/blogger.html]
In the comments to the last entry Frank Patrick raised a “clarity reservation” (TOC-speak for “huh?”). I’m not surprised, those were both entities which assumed a considerable amount of background knowledge – so I’ve added the following two tree fragments: T-i-U dictates strategies people use and People have Model I Theory-In-Use
The entire CRT(Current Reality Tree) so far can be seen in this PDF
While the wiki is offline, here
is the first part of the CRT I’m building from the Argyris book
The work following on from ealier posts 1 2 3 was starting to get too convoluted for blog posts, so I
‘ve set up a Constraints section on the Wiki, and started to document my process there
Having discovered the Twiki Draw plugin, I think a wiki with a drawing tool could well be the perfect tool for developing this sort of exchange…
Continuing to work through Overcoming Organizational Defenses to find links with the TOC approach it struck me that creating a CRT was in itself a form of Cognitive Mapping.
In other words by extracting the key concepts from the book into a CRT it should be possible to graphically display and test the book’s argument at the same time as comprehending it.
In the first chapter Argyris gives some strong clues about the sort of Undesirable Effects (UDEs) we might see in the real world…
As noted in an earlier article I’ve started re-reading Overcoming Organizational Defenses with the intent of seeing how to integrate Argyris’s approach with TOC.
Confirmation that my intuition may have taken me down a fruitful path comes from Chapter 1 “Puzzles”:
“The players in these studies also take for granted policies and practices that are contrary to their managerial stewardship. They bypass root causes. They equate being realistic with being simplistic. They make all these actions undiscussable. They thus wind up creating a world in which the bad is tied up with the good so that producing the latter guarantees the former. Finally all of this is done with the best of intentions”
Which also sounds like the sort of situation a CRT was designed to explore!
I’ve been reading ideas from Mitch Ratcliffe and Frank Patrick on how the technology deployed in a business both embodies and is constrained by the hidden, unspoken mental models held by the sponsors, specifiers, implementers and users of the technology.
Reading this I was reminded of the work of Chris Argyris, particularly the “theory in use”/”espoused theory” difference and organisational defensive routines. I wonder how we might usefully combine insights and tools from those different perspectives?
Phil Wolff is wondering Can you apply Theory of Constraints to Human Capital?.
Interesting questions – although the term “Human Capital” makes me cringe slightly… However in the context of workforce planning one of his questions seems to go to a pretty core issue
“How can we [...] spend more time spent in meaningful conversation and less on paperwork?”
Further to the last article here are a few blogs that make frequent reference to Theory of Constraints together with a few sample posts (some of which they wrote in parallel):
Focused Performance (Frank Patrick):
* Down ‘n Dirty with TOC and Project Management 1 2 3 4 5
Reforming Project Management (Hal Macomber) :
* Down ‘n Dirty with the Theory of Constraints 1 2 3 4 5
* Customers, Promises and TOC
Learning about Lean (Joe Ely)
* Down and Dirty with TOC and Lean
Real life processes are messy and complex – changing them can be risky. With this in mind I’ve started a project in the organisation where I work looking at how we can understand better the problems in our area of the business and find out where to focus our improvement efforts.
We’re using an approach based on the Theory of Constraints. Lots of people have written more eleoquently than I on the details of TOC (See links at end of article) but although labelled “theory” this is a very practical approach that helps you answer three ‘Big Questions’:
- What are we going to change?
- What are we going to change to?
- How are we going to do the change?
We are still at the early stages – understanding how the area we are looking at really works – but already we’re finding that the approach is a great help in seeing what is really going on. As one of the team put it:
When you used to ask me why something didn’t work I could only say “well it’s everything” – now we understand things much better. I don’t think anyone has ever looked at these processes in this way.
That comment illustrates the double appeal to me of these methods – the diagrams and hard logic please the analytical part of my mind but beyond that there is the human benefit from working with a team to help them understand and express their issues in a systemic and systematic way. OK some of that might just be Hawthorne effect but I also believe there is something fundamentally empowering in helping people improve things that matter to them and express their issues in logical ways that can be used to influence others