'Bremmer's book turns in a clever explanation for why things often get worse before they get better'

Why is the NHS going through a period of instability? Here's one answer. Because the increasing need to respond to the long tail of patient preference is forcing the NHS along the J curve of system transformation.

Got that? If not, you've probably not bothered with two of the latest fads in non fiction: The J Curveby Ian Bremmer and The Long Tailby Chris Anderson (editor of Wired).

Both books describe surprisingly common statistical distributions which, the authors argue, often have greater explanatory power than the more widely discussed normal distribution (aka bell curve). Although these tomes deal with North Korea and Amazon.com respectively, read between the lines and the NHS parallels are obvious.

In the case of The Long Tail, the argument is that service providers should recognise that much of future demand will lie not in the mass-market head of the distribution curve but in the many niches found in the long tail of that distribution. So a service that wants - or is driven - to take personalisation and user responsiveness seriously will have to do more than work out what the 'average' punter wants.

Why? Here's an analogy. In English, about 12 per cent of all words in a given text are 'the', while 'barracks' apparently occurs in less than 1 in 60,000 words. But cumulatively, words about as rare as 'barracks' make up about a third of all text - they are the 'long tail' in our vocabulary.

And it turns out that consumer preferences often exhibit a similar shape. Amazon, for instance, has recognised that books in low demand can collectively sell more than current bestsellers. As it explains: 'We sold more books today that didn't sell at all yesterday than we sold today of all the books that did sell yesterday.' (Think about it.)

Relevance to health and social care? As the baby boomers displace the Second World War generation as Britain's new cadre of retirees - and therefore as the high-intensity users of the NHS - expect far greater pressure to respond to diverse patient preferences whether it be for aggressive vconservative treatment, high tech vdying at home, and so on. It will simply no longer be the case that older patients will be content to take what they're given, no questions asked.

As one analyst wrote recently, 'The impact of the ageing population on markets, employers, and culture cannot be overstated. Just as the baby boom flooded maternity wards, ignited school construction, and made &Quot;youth&Quot; the cultural icon of the '50s, '60s, and '70s, the &Quot;senior boom&Quot; of this century will shape the 2010s, '20s, and '30s.' Which is one of the reasons why social welfare systems across the industrialised world are having to restructure.

That's where The J Curvecomes in. Bremmer's book turns in a clever explanation for why things often get worse before they get better. In part it updates the work of James C Davies, who, noticing that the late 1950s was a period of coups, guerilla wars and wars for independence, came up with a theory about rising expectations and the likelihood of armed conflict.

The J curve also turns out to be a pattern observed by epidemiologists (plot hypertension or cholesterol against cardiovascular mortality and you get a J curve), investors (plot private equity returns against time and you often get a J curve), and economists (plot a country's trade deficit after its currency devalues and you get a J curve).

But Bremmer constructs his J curve in a novel way, with the horizontal axis measuring the 'openness' of a system or nation and the vertical axis measuring its stability. In the light of this he shows that while systems that are sealed to the outside world are surprisingly stable (eg North Korea), as the degree of openness and plurality increases, for a time their stability dips (eg East Germany) before rising again (eg France).

The analysis and the shape of the curve contains several important messages. First, for a system on the closed-but-stable left side of the J curve it is far easier to increase stability by becoming more closed and authoritarian than by embracing openness. And second, to move from being a closed regime to an open one a system 'must go through a transitional period of dangerous instability' that may require its leaders to spend huge amounts of political capital with no guarantee of success.

So as one commentator noted, 'In the middle of the J curve, when [systems] that are moving toward greater openness experience a slide toward instability, their leaders must choose between making the complete transition to openness or backsliding toward repression.'

By now you will recognise the relevance to the NHS. You decide for yourself where on that curve the NHS is currently located in its reform trajectory. The new primary care trusts are now three weeks old. Finding themselves somewhere in the middle of that J curve - at the point of maximum wobbliness - what can they do about it?

Organisational psychologist William Bridges talks about two processes in change, both of which need to be planned for and managed. First comes operational change, which is generally external, event-based, quick and defined by outcome. But as important are the slower 'transition' processes of change, which tend to be internal, psychological, and defined by process. These have three distinct phases: endings, neutral zones and new beginnings. The endings phase leads to disengagement; the neutral zone is a time when old habits are extinguished; and the new beginnings period is when people really feel at ease with the new.

Managing these processes well is the hallmark of an organisation capable of successful transformation. Yet these are the things the NHS often does poorly.

So that's The Long Tailand The J Curve. Surely a sequel can't be far behind; perhaps Round the U-Bend: management insights from sanitary plumbing.

Simon Stevens is president of UnitedHealth Europe and visiting professor at the LSE.