Monday, February 11, 2008

Four Stages Of The Demographic Transition

Bo Malmberg's Theory Of Stages, Sanderson and Scherbov's Life Cycle Rescaling and Demographic Maturity

Transition in Phases?

The demographic transition, as is well known, has substantial effects on the age structures of populations (Lee, 2003a). The consequences of such age structure effects have been extensively analysed, and the extent of their impact on both the developed and the devolping world has been widely debated. While the literature on societal ageing contains numerous examples of empirical research documenting these changes (references), there have been surprisingly few attempts to evaluate the process on a theoretical level.

One notable exception in this context has been the Swedish demographer Bo Malmberg, who has proposed a four-phase typology of the demographic transition. This typology may be considered a useful starting point for examining the ways in which systematic age structure changes form a integral part of the transition process itself. In devloping his typology Malmberg takes as his core 'stylised fact' the steady (and seemingly unceasing) upward drift in median population ages which characterise the evolution of most transition and post transition societies following the initial fall in median ages which is associated with the sharp decline in child and infant mortality which characterises the first phase of the transition. What is perhaps most noteworthy and most interesting about Malmberg's work is his attempt to correlate such median age changes with the ongoing processes of social and economic evolution which accompany the 'long duree' of the demographic transition itself (Malmberg and Sommestad, 2000).

The modern demographic transition has, of course, had a substantial influence on both population-size and population growth-rates since its initiation in the United Kingdom at the end of the eighteenth century, and it is probably this aspect of the transition more than any other which has tended to capture the popular attention, at least, that is, until low fertility and population ageing started to hit the headlines. Less well appreciated and less well publicised, however, was the fact that the impact of the transition on the age structure of populations has been equally strong and significant. It is this age-structure dimension which Bo Malmberg, perhaps more than any other demographer, has thought about and has attempted to capture theoretically.

Impacts on age structure tend to be more extended in time than their more dramatic size-impact equivalents, and indeed one might claim that the whole process of the demographic transition in-and-of itself is best thought of as an extended and continuous process of age-transition. This is Malmberg's principle insight.

According to Malmberg, it is possible to break this age transition down into four distinct phases, each of which is characterised by the dominance of one specific age group (the term 'hegemony' does immediately come to mind here). With the onset of the transition (which is, remember, characterised by a sharp decline in mortality, and in particular in infant and child mortality) a child-dominated phase, comes into existence. It seems - in the words of one evocative metaphor - to be 'raining children'. Later, as the fertility transition itself takes hold and fertility begins its decline, there comes a young-adult stage. The acceleration of the fertility decline towards replacement fertility then produces what might be termed the middle-age - or prime adult worker - phase, and finally sustained below-replacement fertility produces in its wake an elderly - or mature - society.

Now before we proceed further, it is perhaps worth taking the time-out to examine an associated but exceedingly important issue: just how 'old' is old? This topic is an interesting one, since it conditions just how we read and interpret Malmberg's stages.

To help us with this Warren Sanderson & Sergei Scherbov have published a very interesting (and thought provoking) article in Nature (Sanderson and Scherbov, 2005), which explicitly addresses the issue of the relative value of the meaning of the word 'old' . The title of the article really tells the story in itself: "Average Remaining Lifetimes Can Increase as Human Populations Age". Put another way: we may now be facing the interesting enigma that, as societies - and collectively speaking - the longer we live, the longer we have left to live.

Riddles aside, what Sanderson and Scherbov actually propose is the establishment of a new metric: the 'standardised median age of the population' which is simply the crude median age figure standardised for expected remaining years of life. Now why would such a metric be interesting?

Well for one reason it would be interesting since it offers the possibility of better using median age as a rough and ready - rule of thumb type - guide for looking at all kinds of issues, from savings and investment behaviour, to social and political phenomena.

Effectively Malmberg suggests that societies with a median age of 'x' "may be expected to demonstrate the following characteristics..........". This approach has its attractions, since it is obviously on some trivial level true. Societies with a low median age and a lot of children need a plentiful supply of schools, teachers, and childminders, those with a high median age need rather old people’s homes, geriatricians and elderly care workers. But generalised too far it also would seem to have its drawbacks. I have long been aware that there is something intrinsically problematic about this way of doing things, and part of the source of my unease has been the gnawing feeling that median age is, as Sanderson and Scherbov explain, a moveable feast.

To try to get to the heart of the issue here, let’s take a simple analogy from economics. Economists often want to make comparisons, say about peoples relative preferences for apples and pears, and how these evolve through time, and in order to make such comparisons they often need to construct elaborate indexes like, for example, the consumer price index. Sometimes, however, economists just want to think about apples, and compare them, for example from one year’s harvest to the next, or from one variety to another. Now one simple way of making comparisons of this type is to think in terms of price, how this changes from one year to the next. But for many purposes this is a rather crude way of doing things, and often it simply isn’t sufficient, since a procedure of this kind ignores changes in quality. So to try and get round this kind of difficulty economists have invented (well better-put Zvi Griliches invented, see Griliches, 1967) a methodology known as hedonics. Hedonics is a procedure which allows us to make comparisons of the price and the quality of one and the same product across time.

Now, in a nutshell, this is what Sanderson and Scherbov are proposing to do for median age: formulate a hedonics of human age value, using remaining life expectancy as a crude proxy. As they say:

”Population ageing differs from the ageing of an individual. People who survive grow older with each year they live. Populations, on the other hand, can grow younger. Because a wide variety of matters such as the cost of medical care, retirement, bequests, consumption and the accumulation of human and tangible capital depend not only on age but also on time left to live, our understanding of population ageing must also re?ect both of these factors. Because conventionally measured old-age dependency ratios (the ratio of the number of people at the retirement age and above divided by the number of people in the working ages) have caused worry about the sustainability of pensions, it is important to recognize that these ratios, rescaled for life expectancy increases, are forecasted to change comparatively little over the century, suggesting caution in our assessment of long-term pension problems.”

One idea that Sanderson and Scherbov implicitly advance (although they don’t in my view make this sufficiently explicit) is that this 'getting younger' constitutes an effective re-evaluation of the prime age working life of the human individual. I think this is the point they are making when they say:

”Medical care expenditures provide an example where calculating the median remaining life expectancy in a population is useful. Health care costs rise rapidly in the last years of a person’s life. The change in the median remaining life expectancy between years is equal to the change in the median time to the onset of that phase of rapidly rising costs.”

That is to say, we shift the more feeble and fragile years up through the age course. In similar vein they also advance the idea of 'proportional life cycle rescaling', which effectively amounts to the same thing.

”Proportional life cycle rescaling is a heuristic not a predictive concept. It provides one simple way of thinking about a complex future in which the lengths of life cycle phases will be influenced by social policies and demographic constraints not modelled here. We use proportional life cycle rescaling by adjusting the conventional start of the working age phase (assumed to be age 20 in the year 2000) and the conventional end of that phase (assumed to be age 65 in 2000) proportionally to changes in life expectancy from 2000 onward.”

So the basic idea that we can take from Sanderson and Scherbov ( and it is an extremely important one) is that we need a benchmark (a calibration date, the year 2000, for example) and a moving-age-index calibrated in terms of the benchmark values. This would then give us a rough and ready but very 'user friendly' measure of just how the productive potential of a given population was changing through time (and, thrown in for good measure, some sort of indication of the future growth potential of the economy in question).

Their point about the relative lengths of the life cycle phases being, in part, socially constituted and thus influenced by social policies is not one to be taken lightly since it has two clear implications. Firstly, the necessary life course rescaling means a continuously later average start date for work. This is also what is meant by the idea of an economy moving continuously up the value chain, as the additional value can normally best be thought of as an increase in the ‘ideas content’ of the final product, and increasing ideas content means increasing education, and this continuing increase in education implies the age at which the young person may be considered fully productive for the new activities which are continuously so created simply rises and rises, as does the age of two other key life course events, setting up an independent home and having the first child.

Secondly it implies an upwardly flexible retirement age. This, as I say may be affected by both social realities (we remain more productive longer) and demographic constraints (rapid population ageing may mean that retirement ages need to rise simply to make the elderly dependency ratio economically sustainable). That there is nothing automatic about the occurrence of either of these ‘transitions’ can be seen from the debates about delayed retirement and other social policy and labour market reforms that are currently taking place across the European Union. Clearly a society's institutional structure is an important mediating framework between individual decisions and aggregate outcomes and there is nothing automatic at all about the evolution of this institutional structure (it is, as they say path dependent), a point which we shall return to later.

Now the question inevitably arises, what exactly has all this got to do with Bo Malmberg? Well Malmberg, let us remember, proposes a transition with a phases typology of age groups, and in thinking about this typology it is important to be aware, right from the outset, that these age groups are not carved in stone.

In the social and natural sciences three theoretical models have been proposed to help us understand human life events, Life History Theory (Biology/anthropology, Kaplan and Gangestead 2004, Charnov, 1993), Life Course Theory (sociology, anthropology, psychology, Mayer, 2001) and Life Cycle Theory (economics, Deaton, 2005).

Malmberg's proposal of age-structure phases (perhaps without his being aware of the fact) cuts clean across all three of these blocks of theory, and it does so in a way which can only be adequately understood in the light of the Sanderson and Scherbov proposal, since if "Average Remaining Lifetimes Can Increase as Human Populations Age" this increase must influence how we classify all the stages in the human life course, and, as a consequence, all the phases in Malmberg's typology. Put in other words, we need to apply the idea of proportional life cycle rescaling not simply to the phenotype, but to the genotype as well (as Sanderson and Schervov argue, population ageing differs from the ageing of an individual) so if we accept the validity of Malmberg’s initial project (and that for many, of course, is a big if) then we also need a 'four-phase transition' rescaling to accompany the individual life course one.

The Four Phases Themselves

Following Malmberg's initial typology, the first phase of the age transition, the child phase, occurs when falling infant and child mortality rates (coupled with improved pregnancy-delivery rates) produce an increase in the number of surving children in a given society. The reason this increase occurs is the fairly self-explanatory one that in earlier high-mortality populations, most of those who die are infants and children. In addition to this initial change, the subsequent process of cohort maturation means that the increasing numbers of children who survive into adulthood reach reproductive age and produce yet more children and so on, since the available fertile population grows continuosly, and this, in the absence of any compensatory downwards movement in fertlity levels, inevitably leads to further increases in the number of children born.

As a consequence at some stage after the initial fall in mortality (and the length of the intervening period involved varies from one country and one culture to another), the age structure of the population begins to assume the concave pyramid shape which has now become so familiar in the context of countries experiencing high rates of natural population growth.

Empirical experience has taught us that with the passage of time fertility rates generally start to gradually adjust downwards, as the demographic transition properly speaking sets-in, and under the impact of this fertility decline the pyramid structure starts to change significantly. Again there is nothing automatic about this process, and much of the research which was carried out under the aegis of the now legendary European Fertility Project was devoted to trying to establish precisely why it isn't, or put another way, what the factors are which influence the onset timing and subsequent intensity of the transition, or, using more contemporary language, why some countries 'stall' and others don't. (Coale and Watkins, 1986).

The reduction in the total number of children born means that the generations of new-born children are no longer – in pyramidal terms - as thick as they once were. More time passes, and the fertility reduction continues with fertility eventually dropping first towards, and then beyond, population replacement level. The steady reduction in cohort size eventually produces a bulge in the age structure - a bulge which pivots around those cohorts born just prior to the absolute decline in the number of live births. The classic population pyramid then changes its appearance into something else: as the base gets narrower the pyramid steadily assumes an increasingly convex shape (that this process is not always and everywhere the same can be seem by the exitence of the boom cohort phenomenon, especially noteworthy in its European and United states post World War II version, and in the impact that large and sustained immigration can have on the pyramid, once again the experience of the United States stands out here).

In the standard (or classical) model of the demographic transition the fall in the birth rate towards replacement level should constitute the last and closing phase of the transition (Lee, 2003). However, as we can now see, replacement fertility does not constitute an end point since the decline continues well beyond this level, with fertility moving onwards and downwards through replacement level, often reaching what some have called 'lowest-low' levels of fertility (1.2 or 1.3 TFRs, even though there is nothing self evidently 'lowest' about these levels in and of themselves, Kohler et al, 2002). However even in the absence of this continuing fertility decline the age transition process would be far from completed at replacement fertility level since a population which has developed a bulge in its age structure will be continuously transformed for as long as the bulge continues its passage across the various ages (with the baby-boomer phenomenon in the United States being currently a good example of just this situation).

Now, armed with this fourfold typology as their starting point and with Swedish data from the late 18th century onwards as their raw material, Malmberg and Sommestad (2000) have tried to specify some of the ideal-type phases (using an expression of Max Weber's, which, it should be noted, Malmberg and Sommestad do not adopt) of the age transition as follows:

The first phase - the child one - began in Sweden in the early 19th century and continued up to the middle of the century. The second phase, the young adult one, started around 1840 and continues to around the time of the first world war. The third phase, that of an expanding middle aged population, started in the 1870s and continued up to the 1980s. Meanwhile the fourth phase, with an expanding old age population, really started in the 1980s and is of course still ongoing. (A word of caution needs to be expressed here since Malmberg's dating is somewhat vague, and seems to incorporate the idea of overlapping phases, a matter which complicates the problem enormously methodologically speaking. Nonetheless, this issue will be sidestepped here since the intention is not to rigourously identify the stages, but to justify them theoretically, and to provide a more rigourous underpinning and interpretation of the whole idea).

Well, so much for the initial theory. But isn't it somewhat crude? Doesn't it simply replace primitive economic determinism with another demographic version which is ridden with all the same attendant problems? I would argue that it does not. In the first place the theory is not really a theory at all, but simply a description: it merely states that during the roll-out of the modern demographic transition it is possible to note a certain correlation between various types of social and institutional behaviour and an evolving age structure. In particular there is no ascription of directional causal arrows here.

Applied rigidly this would obviously immediately become open to all the old criticisms which were initially applied to the most schematic versions of the original transition theory. If, on the other hand, Malmberg's taxonomy is simply treated as a generalisation with significant descriptive properties it seems useful and remarkably insightful.

Now, as as been indicated, one way of taking Malmberg's initial idea forward is to follow the path marked out by Sanderson and Scherbov. However, another useful strategy might be to try and conceptualise the idea in terms of the various life event theories which have been advanced from within the social sciences: Life Cycle Theory (economics), Life Course Theory (sociology) and Life History Theory (biology/anthropology).

Life Course Theory

Sociologists tend to find life course theory useful since it helps them conceptualise the ways in which patterns in life courses serve as mechanisms through which social structures are generated as the aggregate outcome of a totality of individual decisions taken across the life course. One good and highly relevant example here would be the way in which the age and cohort structure of a population is the result of a multitude of individual fertility behaviours and decisions. Looked at the other way round, individual behaviour is itself conditioned by a variety of social and economic constraints, constraints which determine the options available for each individual actor. In this sense any micro-level behaviour is influenced by its given context - this defining feature of human agency has often been referred to by sociologists as "embeddedness", which is a multidimensional construct relating generally to the importance of social systems and networks for actors, an idea which draws attention to the fact that actors integrated within multiple social and institutional networks face varying resource and constraint sets according to the problem at hand (Granovetter, 1985, Luhmann, 1995)

In similar fashion, the decisions concerning major life course events are shaped by an individual’s past experiences and life events. This is sometimes referred to as being the outcome of a process of life contingency and cumulative causation. As Dykstra and van Wissen assert, “early events pave the way for some roles and preclude others, altering life chances and prospects” (Dykstra and van Wissen, 1999: 12). Individuals here are seen as rational actors trying to utilise the information available to them to achieve their assumed goals within a variety of constraints, be they material resources, institutional infrastructures, or cultural norms.

In life course theory, notions of rational orientation and of the interaction between competing itineries are also linked with the concept of strategic behaviour, where the timing of life structuring decisions like parenthood may be conceptualised as forming part of a strategy through which agents attempt to organise their life course. In the context of parenting decisions, much of the work in this area has particularly drawn attention to problems arising in attempts to coordinate employment and family life (Brewster and Rindfuss 2000).

On this level life courses may be considered not simply as the life histories of persons as individuals but as patterned dynamic expressions of social structure. Such dynamics operate in populations or subsets of populations. They are governed intentionally or unintentionally by institutions, and are the intentional or unintentional outcomes of the behavior of actors.

One standard theme which may be found among most life course theorists is that of the diminishing contemporary importance of the ‘standard’ life biographies that seem to have characterised the industrial age. This 'destandardisation process' seems to have been gathering steam in the highly industrialised countries since the late 1960s (Mayer 2001) and side-by-side with this we have seen a closely associated shift towards less prescriptive and more variable life biographies, or 'choice biographies' as some have called them. According to Lesthaeghe “life cycle transitions have become more frequent, less strictly patterned, and more complex.” (Lesthaeghe, 1995: p18) , and this has produced more individual diversity in the timing of various life course transitions (Heinz and Krüger 2001).

At the heart of this recent structural transformation in the life course lies the changing character of the young adult years. These years constitute what some have termed a ‘demographically dense’ period, in that more life-course events occur between the ages of 18 and 29 than at any other stage of the life course (Rindfuss 1991).

During the last quarter of the twentieth century the lives of young adults living in 'post industrial' societies have changed dramatically. This change can be seen in a whole variety of settings: in prolonged education, evolving and flexible social norms, changing patterns of home leaving and partnership formation, and in the arrival of a whole new card deck of risks and uncertainties. The term 'destandardisation process' is now used by many to describe the way the “classic sequence of finishing school, entry into labour force, home leaving linked to marriage and subsequent parenthood is being reordered in ever larger segments of the population.” (Lesthaeghe and Moors , 2000: p153)

The proces here is a complex one since, on the one hand, young people today enjoy an unprecedented freedom of choice in personal matters (with many of them embracing what Mayer has loosely termed ‘hedonistic individualism') wherein young adults assume responsibility for their own “life designs and life projects or, rather, follow egoistically the shifting material incentives and consumption idols from situation to situation” (Mayer, 2001).

On the other hand, new constraints and new uncertainties, ones which are related above all to employment stability, have emerged in the lives of young adults. In particular young adults are increasingly having to cope with the existence in perpetuity of what would have previously been considered to be non-standard employment contracts, where spells of unemployment are regularly interspersed with periods of part-time work and part-time study and, from time to time, full-time but short-duration employment contracts. For females the situation has become even more complex, since they often find themselves “alternating between non-standard forms of participation in work, education, and family life”.

In general, the life-transitions that traditionally served as the milestone indicators for reaching adulthood - such as leaving the parental home, marrying, and entering parenthood - have both moved upwards in terms of age, and become more flexible as to their timing, and they are now certainly largely to be found outside the long-accepted boundaries which once separated youth and adulthood. And all of this has been accompanied by a growing fluidity and diversity in partnerships and pathways to parenthood (Rindfuss 1991). So rather than a strict ‘sequencing' process, what we now see is the operation of a number of commonly shared concepts of what constitute the necessary preconditions for parenthood in operation. Foremost among these are: leaving the parental home, finishing education, and accumulating resources.

The foundation block for the entire process is really economic independence, and it is the interpretation of what this means which governs the household formation process. One implication of this in an era of heightened individualism and rising consumer aspirations is the idea that the household needs to depend on two permanent incomes rather than one and this in itself may delay marriage and childbearing, and particularly in the more 'familiaristic' societies of Southern Europe (see Dalla Zuanna, 2001 for the Italian case).

Males in particular, it has been argued, often attach considerable importance to the achievement of certain classes of consumer goods, and their appetite for, for examply, new-tech products may well get priority over family formation (Goldscheider and Kaufman 1996: 89). Females on the other hand may attach more importance to the partnership selection procedure given the growing uncertainty about partnership stability and the high level of parental investment required of both partners in raising fewer but better prepared children. The increase in both own- and offspring- investments which the quality/quantity trade-off in offspring implies has lead a number of researchers to speculate that this process may well lead to greater selectivity on the part of females when identifying a suitable partner with whom to co-invest in children. This selectivity is on the one hand a result of the crucial role of both maternal and paternal skills-based investments in the development of offspring, and the unequal distribution of these investments between the sexes. (Kaplan, 2003)

Summarising all this, Mayer indicates that the principal components of the post-transition life course regimes are:

• the age of leaving the parental home,

• the age of leaving school or formalized training,

• the process of labor market entry,

• the rate of fluctuation as work life mobility between firms,

• the rate of work life mobility between occupations,

• the shape and distribution of income trajectories,

• the degree of career involvement of women,

• the fertility and the stability of partnership unions,

• the median retirement age and its degree of dispersion

(Mayer, 2004)

One major structural feature of all life courses is evidently their internal temporal ordering, that is, the relative duration of each of the various states which the life course embodies, as well as the age distributions of the various events or transitions.

Using data from the West German part of the German Life History Study Brückner and Mayer have illustrated just how the timing of key life events such as age of school leaving, termination of education, leaving home, first marriage and age at first childbirth varied among German men and women across the twentieth century (Brückner and Mayer, 2005). Interestingly the educational data reveal a constant upward movement in termination dates while the family decisions timing is more complex, first falling and then once more rising.

Median age of school leaving for males, for example, rises from 14.3 for the 1920 birth cohort to 17.2 for the 1971 one (for females the figures are 14.4 in 1920 and 17.6 in 1971). Median age at first employment for males rises from 18.1 for the 1920 cohort to 20.3 for the 1971 one (for females the figures are 16.9 in the 1920 case and 20.4 in the 1971 one).

Median age on leaving home first falls, before then once more rising, for males falling from 29.7 for the 1920 cohort to 23.3 for the 1950 one and then rising to 24.2 in the 1971 cohort (for females the figures are 28.3 in 1920, 20.8 in the 1955 case and 21.8 in the 1971 one).

Median age at first marriage reveals a similar pattern, with the age for males falling from 27.7 for the 1920 cohort to 25.8 for the 1950 one and then rising to 29.2 in the 1964 cohort (for females the figures are 23.3 in 1920 , 21.5 in the 1950 case and 25.5 in the 1964 one). Similarly with median age at first childbirth, the age for males falls from 29.7 for the 1920 cohort to 27.3 for the 1940 one and then rises to 32.6 in the 1964 cohort (for females the equivalent figures are 25.4 in 1920 , 23.8 in the 1940 birth cohort case and 28.1 in the 1964 one).

One perennial question which arises in this context is just how does such ordering and regularity in life courses come about?

The sociologist Karl Ulrich Mayer has given three answers to this question (Mayer, 2004). Ordering and regularity arise due to:

1/. the process of internal differentiation of societies into subsystems or institutional fields

2/. the internal dynamic of individual lives in group contexts.

3/. the fact that the ordering is not simply the result of the interaction of society on the one hand and the individual on the other but that there is an intermediary structure of aggregates of individuals in the form of populations such as birth cohorts or labor market entry cohorts and the mediation of the activity of these aggregates through institutions.

An evident question then arises: what were the institutional configurations that characterised the various life course and age structure regimes that have been identified by Malmberg and Sommestad above? The following may be considered a preliminary suggestive list:

In traditional societies the life course regime was regulated by the demographics of high mortality and high fertility, and by the prerequisites and vicissitudes of a rural economy which was organised in the absence of such stabilising elements as the agrochemical fertilization or the use of scientific animal husbandry. Following the onset of the transition existence became fragile and children were many. This would be Malmberg’s child-dominated society. The structure of life course decisions reflects this instability, in particular this can be seen in the strategic decision of females to generally reproduce at an early age.

The early industrial life course regime is formed of course against the background of an incipient capitalist economy, in the presence of comparatively weak and unstable labour movements and - under the impact of the early stages of the modern demographic transition - a high labour supply. This is Malmbergs young adult society, with continuing large (if reducing) birth cohorts and weak political, legal and institutional infrastructure. One consequence of this was and is the widespread existence of large scale emigration.

The life course regime in the later industrial societies normally occurs in the presence of an implicit contract between capital and labour, often accompanied by the existence of mass membership trade union organisations. The industrial society was characterised by the presence of mass production technologies and mass 'standardised' consumption goods. Macroeconomic policy intervention increasingly stabilized economic cycles, and full life-time employment, rising real wages and standards of living, and welfare state insurance regimes characterise the social and economic sphere. In other words the regime evolves in the presence of a strong and 'unifying' institutional framework which includes sub-systems (like the educational one) which nourish standardisation. This would be Malmberg’s mature adult society.

With the arrival of the postindustrial, or knowledge, or services-dominated societies, the life course regime has once more witnessed significant changes: sustained educational expansion into the tertiary stage, growing female emancipation, accelerating value changes, growing individualization and self-direction, weakening of organised labour, growing de-industrialization, flexibilised labour markets and the ending of life-time employment, globalization of economic markets, and sizeable demographic changes (fuelled in particular by an extended postponment of childbearing), low fertility levels and greatly increased life expectancy the combined operation of all of which has lead to a significant inversion in the classical age pyramid, and, of course, the arrival of Malmberg’s elderly society. This process has been accompanied by a loosening of the late-industrial institutional framework with a continuing degregularisation of the welfare system, a weakening of 'standard' life biographies, and the flexibilisation of nearly everything.

One way in which many life course theorists have treated these transitions has been to focus on changes in what has become known as the 'welfare mix' (i.e., the relative importance and manner of interconnectedness of economic markets, the family, and the state: see Esping-Andersen, 1999) and the age-directional flow of resources (Lee, 2003b).

Applying the Theory to Sweden

Now if we attempt to look at how these two sets of ideas (life course theory and proportional life cycle rescaling) might be applied to Malmberg's original template , the first thing which should strike us is that different regions in the world have, naturally, experienced the demographic transition (as well as the accompanying age structure and life course transitions) at different points in time, and with varying degrees of intensity. However we could equally note that once the transition is actually under way, the different regions tend to pass through Malmbergs four phases in remarkably similar fashion.

The most important consequence of the age structural changes, at least when viewed from a life cycle perspective, is the fact that an individual's productive capacity and their economic behaviour vary across the cycle. Newborn humans are unable to survive without the adult support. Many years of care, education and training are needed before children have acquired the cognitive skills and productive potential of an average adult.

Similarly, once we have aged beyond a certain point (even though, following Sanderson and Scherbov's proportional life rescaling idea, this point may constitute a kind of moving target), our productive capacity will inevitably begin to decline, until finally our ability to fend for ourselves falls short of what we need to provide for our own survival.

In sharp contrast to both these stages of the life cycle, the years in-between are a time when most adults have a capacity to produce which goes well beyond what they need to guarantee their own immediate survival, and indeed in post-industrial societies seem able to furnish the wherewithall to satisfy what appear to many to be even the most exotic of needs. Put simply, our productive capacity initially is limited, grows steadily with age, rises to a peak and then eventually enters decline, in the course of this life cycle the hump-shaped curve traditionally associated with lifelong earnings and productivity is produced. Essentially the curve is the product of an age related trade-off between experience and speed. (Richerson and Boyd, 2001)

The Life Course/Malmberg Fushion

Using Weberian ideal-type terminology, Malmberg suggests that child dominated societies tend to be inherently politically unstable. They also tend to be poor. A statistical analysis carried out by Malmberg and Sommestad shows that a one percent increase in the share of children in a society is associated with a 2.5 percent increase in the poverty rate. Indeed they find that the share of children in a population explains slightly more than 50 percent of the regional variations in poverty. The sub-Saharan African states have at present remarkably high child dependency rates, and these countries are of course also among the poorest in the world. (Bloom and Sachs, 1998).

Another characteristic feature of child abundant economies is the widespread presence of child labour, a phenomenon clearly connected to their state of poverty. (Cunningham and Viazzo 1996, de Coninck-Smith et al 1997).

A third characteristic feature of child abundant countries is a strong dependence on the exploitation of natural resources. In Sweden, for example, the area of land under cultivation roughly doubled during the early phase of the age transition, from 1820 to 1865. Such cultivation reached a maximum around 1920, a point in time when the proportion of children in the population was at its height. From this time on expansion in agriculture became intensive rather than extensive, with productivity improvements meaning that increased output could continually be achieved with the cultivation of ever smaller total quantities of land.

Today, land reclamation is still an important issue in many countries with rapidly-growing, child-abundant populations. Countries, for example, in sub-Saharan Africa. Between 1980 and 1996 land reclamation was particularly intense in West Africa, with increases between 20 and 40 percent in the share of arable land in countries like Gabon, Guinea, Burkina Faso, Ghana and Côte d'Ivoire.

Finally, child abundant countries are enormously dependent on foreign capital. Malmberg directs us to the work of Lennart Schön, who has systematically studied the history of Swedish trade and the behaviour of its current account balance. He found that Sweden’s current account status was negative for 60 years, from the 1850s up to the end of the first decade of the twentieth century . Indeed, by 1910, Sweden was one of the most indebted nations on the planet, with total estimated debt amounting to some 75 percent of GNP (Schon, 1994).

In Sweden the young-adult phase (from 1840 to WWI) was strongly associated with modernisation (both political and social). This was a time of agricultural transformation, liberalisation, railway building, emigration, urbanisation, industrialisation, popular movements, and, towards the end of the phase, rapidly falling birth rates. New industries emerged, international trade developed, and financial markets boomed and collapsed.

Furthermore, the increase in the share of young people coincided with increasing social and political conflict, and, as a response to this, there was increasing democratisation and the development of a more extensive state involvement in the economy.

The third phase (the rapid expansion of the prime age worker population) was characterized in Sweden by the evolution of much more stable economic conditions. In Sweden this phase probably commenced in the 1930s and continued up to about 1980. If we look for common characteristics among countries that have entered this phase, the most obvious feature which stands out is the presence of sustained economic growth. Countries that for a number of decades have benefited from increases in the the specific weight of their prime age workers in most cases have gone on to become full-members of the OECD. An increase in the group of middle-aged people is thus clearly associated with a more developed stage of economic growth, a stage that the economist Walt Rostow once designated ”the drive to maturity” (Rostow, W.W. 1990)

The final phase of the age transition, the "mature/elderly" phase, is largely a late 20th century phenomenon. On the Malmberg schema this phase is reached when the enlarged cohorts which mark the earlier turning point reach retirement age. Concurrently fertility continues its decline to below replacement levels. As this phase is only really now opening it is hard to specify clearly the eventual defining characteristics.

Two features, however, do stand out.

First, ageing countries have experienced a decline in their rate of economic growth, along with a number of related negative economic trends (like an associated weakening in consumer demand and a rise in the level of saving in excess of demand for investment). Statistical analyses of OECD data reveal a negative association between, on the one hand, the population share aged 60 and above, and, on the other, per capita income growth, productivity growth, rate of capital formation in the business sector, and housing investments. (Analyses based on data in OECD, Statistical Compendium, Vol. 97:1, Paris, 1997; Lindh and Malmberg 1999)

Secondly, population ageing in the OECD countries has been closely connected with growing public expenditure and budget deficits. There is thus a strong positive association between, on the one hand, the share of people aged 60 and above, and, on the other, government consumption, public sector employment, public debt, and taxes paid. All in all, these correlations indicate that the elderly phase of the age transition is associated with a major structural shift in the economy away from a traditional high-growth society towards an economically less vigorous welfare-dependent state. If these results are compared to the life cycle behaviour story, it is evident that the decreasing productive capacity that marks individual ageing also translates itself into significant macroeconomic consequences.

Malmberg uses the terminology elderly society for this fourth stage, but there may well be good theoretical justification for abandoning this use. In particular the expression 'elderly society' implies in and of itself the end of some particular road. For that reason the term 'mature society' will here be preferred. Since this expression implies that something stable - like, for example, the homeostatic end state of a completed transition - has been achieved. In this sense it becomes something normal, and to be welcomeed, rather than something strange and preoccupying.

The terms 'ageing' and 'elderly' society do on the other hand have a certain validity when applied in the context of either an excessively rapid decline in fertility (or rise in life expectancy) which change the balance between the various (age rescaled) life course groups. Thus a rapid first birth postponement process may produce what some have termed a 'birth dearth' while it is taking place, and this, of course, can lead to excessive ageing which cannot be compensated for by changes in age-related capacities. Also institutional (path dependent) rigidities which impede fexible adaptation to the ongoing life-course and life history changes (such as, for example, failure to adapt the working age and retirement classification systems) can produce social and economic 'bottlenecks' which may, if left unchecked, give renewed meaning to that vastly overused expression 'the ageing problem'.


In a recent presentation, Lutz, Skirbekk and Testa (Lutz et al, 2005) argued the following:

"Viewed under a long-term perspective, the demographic transition taught us that the balance of births and deaths (if we assume that systems eventually will move towards homeostasis) can be disturbed

for many decades due to the fact that fertility is strongly embedded in the system of social norms and that such demographic regimes can be very persistent once they are well established."

"Because of this we have seen many decades of “overshooting” birth rates that have resulted in historically unprecedented population growth. It cannot be ruled out that the same forces of social momentum, once a new low fertility regime has been established, will result in decades of “undershooting” birth rates resulting in historically unprecedented population ageing".

Now this statement is interesting in the sense that it assumes that the balance of births and deaths may be regulated homeostatically, even if the homeostatic mechanism which does this is not specified. This allows the authors to use terminology like 'overshooting' and 'undershooting' in relation to fertility.

In this paper I have argued that thinking about this demographic transition process in the context of Bo Malmberg's idea of four phases for the transition and mapping Malmberg's insight onto Sanderson and Scherbov's idea of 'proportional life cycle rescaling' and via the template offered by life course theory might provide us with a very useful framework for understanding the transition process, in particular as it enables us to capture the transition as one from youth to maturity, in both the chronological age and in the institutional senses of the term.

Basically it has been argued here that the Malmberg idea is fruitful but flawed. It is flawed since since it is excessively mechanistic: it is almost a modern 'demographic materialism'. It also has the problem that simply speaking of an elderly society tout court leaves us scratching our heads trying to answer the rather problematic question of what happens next.

If however we map Malmberg's phases onto Sanderson and Scherbov life cycle rescaling we may

arrive at a more theoretically interesting destination: social maturity. If, instead of terming the last phase

in Malmberg's typology the 'elderly society', we simply called it the 'mature demographic regime' then, thinking homeostatically, and imagining for a moment that homeostasis might mean that declining fertility and increasing life expectancy just balance each other , while the proportional life cycle rescaling property works so as to just keep the balance in balance, then we may have what so many people have long been looking for: demographic sustainability.

Of course, as one rather well-known German-speaker once said 'theory is grey, while life is green', so things will never actually be just like this.

Howver this is where Lutz's 'overshooting' and 'undershooting', fertility traps, and path-dependent lock-ins etc etc etc come into play. The bottom line here is that while this way of looking at things would not solve all our problems with a click of the fingers, at least it would offer us a sound theoretical yardstick with which to assess the problems themselves.


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