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A Guide to Implementing the Theory of
Constraints (TOC) |
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Evaluating Change When we set out to implement
change we must remember that there are 3 possible outcomes. These outcomes are; (1) A
change which is a significant improvement. (2) A
change which is neither a significant improvement nor a significant decline. (3) A
change which is a significant decline. Naturally enough, it is
the first option that we are really seeking.
We want to make a difference, and we want that difference to be
manifestly positive. In order to do
so, we must make decisions prior to carrying out the desired actions, and to
be certain in the knowledge that those decisions will deliver the necessary
results that we seek. How we evaluate the
improvement will depend upon the goal of the system. If the goal is a monetary one, then the
evaluation is relatively straightforward.
And that is what we will concentrate on here. In not-for-profit, or more correctly,
for-cause situations how we evaluate an improvement is a little more
involved; however, if you look at the argument for healthcare (supply chain
section) then you will find some good indications of how this can be
achieved. We are evaluating changes
within the context of the whole system – or the system as a whole. We are not interested in local improvements
that do not have system-wide impact.
How, then, would we judge an impact in such a circumstance? We need a context. We already have one, let’s revisit it. On the measurements page
we derived our rules of engagement.
These tell us how to define the entity that we want to improve. We define the boundaries, the goal, the
necessary conditions, and the fundamental measurements. Without these, we do not have a context
within which to evaluate change.
Moreover, this forces us to determine what it is that constrains us
from moving towards our goal; we have to define the role of the constraints. The constraints are
central to our ability to move forward.
In order to define the role of the constraints we need to invoke our
plan of attack, the one we developed on the process of change page. Of course, our plan of attack is Goldratt’s
focusing process. The second step of
this plan, where we decide how to exploit the constraints, is the step that
provides commonality between these two schemes. We have previously
summarized the relationship between the rules of engagement and the plan of
attack as follows;
In order for a change to be
an improvement it must either have a direct positive effect upon the current
exploitation or elevation of the system’s constraints, or an indirect effect
via improved subordination which in-turn ought to improve the exploitation or
elevation, either now or in the future.
To quantify these effects
we must return to our fundamental measurements. In the first page, the
page on measurements, we briefly introduced the concepts of; throughput, inventory/investment,
and operating expense; a triumvirate set
of measures for quantifying effects in Theory of Constraints. Throughput as you may
remember was described as; Throughput
= Sales - Totally Variable Costs From this we came to
define our net profit as; Net Profit
= Throughput - Operating Expense And return-on-investment
is;
The reason that we can do
so much with so little is because of the fundamental relationships that exist
between each measure. They are systemic. Let’s try to reinforce
the fundamental and systemic nature of these measures by way of analogy. By this means we will be in a far stronger
position to understand change and how to evaluate it. The analogy is a see-saw. A see-saw!
How does the evaluation of change relate to a see-saw? Well, let’s have a look. Let’s draw a simple see-saw as a start.
The two equal masses – “people” are located
equidistant from the mid-point of the plank, so let’s label that.
Let’s see.
Can we use this simple analogy of a see-saw for
evaluating internal management decisions, change in other words? In terms of physical
aspects it is apparent that we seek to leverage inputs of some
kind via a process of some sort in order to produce outputs. In fact, the process does not exist in
isolation but rather it exists in conjunction with a set of operating
assumptions; the things that we call policies. How then would this look using our
model? Let’s see.
How then would our model look in terms of financial
aspects? In the terms of financial aspects it is apparent that we seek to leverage
expenditure via investment to produce income.
Once again the investment does not exist in isolation but rather it
exists in conjunction with a set of working assumptions; policies once
again. Let’s see how this looks.
We need to ask then; will this simple analogy, a
see-saw, also work as a description for evaluating change in Theory of
Constraints? Well, I think so, so
let’s try.
It seems then, that our analogy will hold for our fundamental
measures. Great. Any change in throughput, or operating expense may
change the balance of our system. Do
you agree? Our analogy shows the
interrelationships between these various aspects. Do you want to push the analogy a little bit
further? What is our profit then? Let’s have a look.
What about the balance point then?
We know the location of the balance point, but this
begs a question. What is the fulcrum
that we leverage across? Let’s have a look.
I know that all too often we loosely talk about
leveraging the constraint – we have used that language throughout these
webpages and it is probably ingrained.
But in reality we are leveraging our entire system
over the fulcrum – time – and the only
way that we can do that, either literally or metaphorically, is via the
constraint. So we leverage the
system via the constraint for a given unit of time. So, yet another question; what exactly is the
constraint in our analogy then?
Now that we have identified
the constraint, how can we get more of this limiting factor? How in our metaphor can we get more people
sitting balanced on the right-hand side?
How can we improve the Throughput?
How can we improve the profit?
There are two answers to these questions, and they are that we can
increase the productivity, and/or we can increase the production. We need to tease these two strands apart in
order to better understand each of them.
Let’s do that. Making a distinction between productivity and
production is important in understanding how to most effectively drive
improvement, and such a distinction is also useful in developing our
understanding of the dynamics of exploitation, subordination, and elevation. Production is the simpler, and certainly
more familiar of the two concepts, so let’s start with that. Essentially any increase in production is a pro rata
increase in both inputs (operating expense), and outputs (Throughput). Let’s investigate this with our see-saw
analogy. Let’s start again with our original model with a
balance point located 3/4 of the way along the plank.
Increasing production, seductive as it is – after
all this is what almost everybody else does – is nowhere near as sexy as
improving productivity per se.
Moreover, if we were to go around doing what everyone else does then
there is hardly any strategic advantage to be had at all. So let’s investigate the impact of
improving productivity; many people talk about increasing productivity but
few actually manage to do it. Doing it
is not at all difficult if we have focus. Rather than settling for a pro rata increase in both
operating expense and throughput, which means constant productivity – only
more of it, we actively seek to decouple throughput from operating expense,
which in-turn means increased productivity.
Throughput should increase and ideally operating expense should remain
static or even decrease; something other than additional operating expense
drives the additional throughput. It
is the leveraging of the entire system via the constraint’s throughput
relative to the fulcrum, time, that drives the additional throughput. Let’s show this by example. Let’s start again with our original model with a 3:1
ratio.
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