Breaking down the question
This is a thinker-specific question worth thirty marks, so it demands both depth and structure. The examiner names Davis and Blake explicitly, which means you must reproduce their actual framework — the analytical scheme of intermediate variables they set out in their 1956 paper, and the way it links fertility to social structure. A general essay on why birth rates vary will not do.
The heart of the answer is their central insight: social structure never acts on fertility directly. It acts only through a limited set of intermediate variables — the biological and behavioural steps of reproduction — and cultural norms, institutions and economic conditions influence fertility by influencing these variables. Your task is to explain the scheme, illustrate the three stages, and then draw out the sociological implication: fertility is a social fact, governed by the organisation of society, not merely a biological given.
How to approach it
Open by placing Davis and Blake within the sociology of population and stating their governing thesis — that the effect of social structure on fertility is always mediated by a set of intermediate variables through which any social or economic factor must operate. Explain why this was an advance: it gave demographers a systematic, exhaustive framework linking the social and the biological. Our notes on the components of population growth situate fertility among the wider determinants of population change.
Then set out the eleven intermediate variables under their three groups — those governing intercourse, those governing conception, and those governing gestation and successful parturition. For each group give concrete examples of how social norms and institutions operate through it: age at marriage and the incidence of celibacy affect exposure to intercourse; norms around contraception and abstinence affect conception; attitudes to abortion affect gestation. Then broaden out to show the relationship with social structure — how family systems, religion, economic organisation and the status of women shape these variables. Illustrate with the contrast between high-fertility agrarian societies and low-fertility industrial ones. Conclude with an appraisal: the framework's analytical power and its limitations.
Model answer
The relationship between fertility and social structure was given its most influential analytical formulation by Kingsley Davis and Judith Blake in their 1956 paper on the social structure of fertility. Their achievement was to show, with unusual rigour, exactly how the vast and varied features of a society — its family system, religion, economy and morality — come to bear on the number of children that are born. Their answer was that social structure never touches fertility directly; it can only work through a fixed and limited set of channels, which they called the intermediate variables.
The logic is compelling. Any child that is born must pass through three necessary stages: sexual intercourse, conception, and successful gestation ending in a live birth. Every social or economic factor that affects fertility — a religious teaching, an economic incentive, a marriage custom — must ultimately raise or lower fertility by acting on one of these stages. Davis and Blake therefore drew up an exhaustive list of eleven intermediate variables grouped under the three stages, arguing that this scheme captured every possible route by which society could influence the birth rate.
The first group concerns exposure to intercourse. It includes the age of entry into sexual unions, the proportion of people who never enter such unions, and the amount of reproductive life spent within and outside unions — through widowhood, divorce, separation or the absence of a spouse. Here the marriage system is decisive: a society that marries its women early and universally, and that discourages widow remarriage while still exposing young wives to intercourse, will generate high fertility, whereas late and less universal marriage, as in industrial societies, reduces it.
The second group concerns exposure to conception. It includes voluntary and involuntary abstinence, the frequency of intercourse within unions, involuntary sterility, the use or non-use of contraception, and voluntary sterility through sterilisation. Norms around breastfeeding, post-partum abstinence, and above all the social acceptability of contraception operate through this group. A society in which family planning is normatively approved and economically desired will see fertility fall through deliberate control of conception.
The third group concerns gestation and successful parturition. It includes foetal mortality from involuntary causes and from voluntary causes — that is, induced abortion. Attitudes shaped by religion, law and morality towards abortion operate at this final stage.
The sociological force of the scheme lies in what surrounds these variables. Social structure — the family and kinship system, religious doctrine, the organisation of the economy, the status accorded to women, prevailing values about children — constitutes the environment that sets the intermediate variables at high or low values. In an agrarian, patriarchal society, children are an economic asset and a source of security in old age, marriage is early and universal, and no norm favours limitation; the intermediate variables are accordingly set for high fertility. In an urban, industrial society, children become an economic cost, women pursue education and employment, marriage is delayed, contraception is approved, and the same variables are set for low fertility. The famous contrast between pre-transition and post-transition societies is, in this framework, a contrast in the way social structure configures the intermediate variables.
The framework is not beyond criticism. It has been faulted for being descriptive rather than explanatory — for listing the channels without weighting them or predicting outcomes — and for treating the variables somewhat mechanically, in isolation from the meanings people attach to childbearing. Later scholars, including Bongaarts, refined it into a smaller set of proximate determinants better suited to measurement. Yet the essential contribution stands. Davis and Blake established, once and for all, that fertility is a social phenomenon: biology sets the outer limits, but it is the social structure, operating through the intermediate variables, that determines where within those limits a society's fertility will fall.
Examiner's perspective
At thirty marks the examiner expects the candidate to reproduce the Davis-Blake framework accurately, not to write a general essay on population. The single most important discriminator is whether the answer names the intermediate variables and organises them under the three stages of intercourse, conception and gestation, since this scheme is the whole point of their contribution.
High-scoring scripts explain the governing thesis — that social structure influences fertility only through these mediating channels — and then illustrate each stage with real social norms and institutions, before broadening to the contrast between agrarian and industrial fertility regimes. A concluding appraisal that notes both the analytical power of the model and its descriptive limitations, perhaps referencing Bongaarts's later refinement, demonstrates the critical depth the higher band requires.