First published Dec 8th 2011
As a physicist by inclination, I often gain useful insight through metaphors which draw on the science of “stuff”. The experiment of loading a wire or spring with different weights (a pure physicist would insist on talking about “masses”) is one I am sure most people will recall from school days. The heavier the load, the more the wire stretches. Up to a certain point, most simple materials stretch in direct proportion to the load. This property of stretching is called “elasticity”. The force acting through the length of the spring when the weight is added is called “tension”. But a fine wire is weaker than a heavier gauge wire. This is because the tension acting in the spring is spread across the cross sectional of the wire in the spring. The impact of this tension in the wire is “stress”: – the force per unit area. The amount that the spring stretches compared with its original length is called “strain”.
Now, all this was discovered by Robert Hooke, a physicist who was a contemporary of Isaac Newton. He gave his name to Hooke’s law which states that for a given material (none of the clever composite materials in his day – this was all about metals), the strain is directly proportional to the stress, so that the ratio between them is a constant property of the particular metal – the “coefficient of elasticity”. If we get right down to detail, other parameters such as temperature play their part and will change this coefficient – the hotter the spring, the bigger the strain for a given stress.
What Hooke’s law means is that when we remove the load, the wire or spring returns to its original length. Take away the stress and the strain goes back to zero. But, if we keep on piling on the load, the wire starts to stretch much more than we expect – Hooke’s law has run out of steam! And now, when we remove the load, the wire no longer returns to its original length – it has a permanent distortion in it. The stress applied was so great, that we changed the properties of the wire in a way that cannot be changed back by the simple processes of changing the load. The point at which permanent distortion starts to happen is called the “elastic limit”. When we have applied stress greater than the elastic limit, physicists describe the behaviour as “plastic”. Plastic strain is that change which happens to a material when we have loaded it up so much that its behaviour is no longer predictable according to Hooke’s law.
In the plastic region, the relationship between the variables (the cross section, the length, the coefficient of elasticity and the total load applied) ceases to be linear, because very small effects (called second order effects) start to become too large to ignore. In the case of the metal wire, the forces applied are sufficient to change the way the microcrystals relate to each other. Typically, at one point in the wire, necking will occur where the rearrangement of the crystals in the direction of the force will cause the wire to narrow. The friction of the crystals rubbing past each other will heat that part of the wire. The smaller cross section means that the stress is higher, and the temperature increase means that the strain will increase for a given stress. As more external load is applied now, more damage is done concentrated at this narrowing, until at some point the wire breaks. We refer to this point as the breaking strain, reflecting the fact that any material can only be distorted so far from its natural state before the strain simply becomes too much, and instead of stretching further, it snaps.
As one final aside, there are some interesting things you can do to change the coefficient of elasticity, to change the elastic limit and the breaking strain. Metallurgists will be familiar with work hardening (the black-smith hitting the hot metal repeatedly), or case hardening (treating the metal surface to change its composition slightly), or annealing or quenching – heat treatments that also change the surface and the crystalline composition. Interestingly, some of these treatments can strengthen the material so that the strain is reduced, but at the same time might reduce the elastic limit or breaking strain, so that it has a more limited range over which its behaviour remains predictable and elastic.
Now the fact that you are still reading, suggests to me that you are either a physicist, checking out my details, or you have latched onto my analogue. The language of tension, stress, strain, elasticity, breaking point, all relate to experiences in other parts of your life. You can see the parallel in mental or physical health, or the working environment – different people exhibit a different relationship between stress and strain, and this relationship can be strengthened by workout, so that the strain arising from a given stress can be reduced. Some have an elastic limit much lower than others, so they start to behave out of normal character at a much lower threshold level, and others might appear strong for longer but break very quickly after passing their elastic limit.
But the analogue I want to touch on is that of organisations. Organisations are elastic – they respond to forces being applied to them, which in turn translates into stress acting within the organisation giving rise to strain – the changed shape arising as the organisation reacts to the stresses. An organisation is more complex than the simple wire, nevertheless, if the stresses are applied within the elastic limit, the organisation will continue behaving exactly as before – take away the stresses and it will return to its original shape. Increase the stresses and it will react predictably, until it has been pushed beyond its elastic limit. The properties of the organisation can be changed by organisational development which can strengthen it against the stresses, to make it more resilient. But the truth is, when you need to effect major change, it is essential to push it beyond the elastic limit, creating some permanent lasting change because the relationships between the atoms and the forces binding them together have been permanently changed. And when you push something beyond the elastic limit to avoid it bouncing back unchanged, it is critical to be mindful of the breaking strain which leads to permanent, irrecoverable damage.
Now, everywhere I turn at the moment, people are talking about the need to create disruptive innovation in the health system. But this is in real danger of becoming another fad, rather than a serious and fundamental approach to management science and understanding. I even heard it said recently that we want disruptive innovation without the disruption. And to understand what it is we need to disrupt, it is crucial to look at the “atoms” and “forces” which contribute to the resilience and elasticity. We talk about these as the silos – the “microcrystals” of our wire. These include the individual teams and 400 plus organisations within the NHS. They include the professional silos designed to protect individual professional standards. The financial forces designed to reward fragments of care. The education processes that are grounded within current cultures. The research processes. The political processes, especially the Kidderminster effect! The media frenzy which misleads the public into fighting any change!
Disruptive innovation means pushing each of these areas beyond their own elastic limits – some areas will distort plastically, but others will undoubtedly exceed the breaking strain. If this is not happening, painful though it might be, the organisational elasticity will ensure that the current system lives to fight another day, on precisely the same basis as we are losing the battles today. Ultimately, it is the business model which needs to be disrupted, because this defines the architecture within which all the ingredients are held and work together. The need for competition, and innovation, and new forms of professionalism and regulation are all part of the new business model(s). Disruption, and the painful stresses and strains are essential. Bring them on!