Population Investigation Committee

Family Intentions. by Myra WoolfReview by: Christopher LangfordPopulation Studies, Vol. 26, No. 2 (Jul., 1972), pp. 333-335Published by: Taylor & Francis, Ltd. on behalf of the Population Investigation CommitteeStable URL: http://www.jstor.org/stable/2173601 .

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BOOK REVIEWS 333

and a stable population find their place here; further- more, models (sketched already in the New York paper) of linear decrease in fertility with stationary mortality and of stationary fertility with linear decrease in mort- ality; finally, partial models of fertility and of migration more by reference to current research than by novel exposition. In the book as a whole, the notation is consistent throughout and, it appears, can be easily

assimilated by the user. The reviewer has, however, not looked for possible errors (pace the first edition of Moroney's 'Facts and Figures'), but did note some textual misprints, also in the cross-references; as early as p. 20, Deometrie for Demometrie - which surely was far from the author's mind.

E. G. JACOBY - Wellington (New Zealand)

Family Intentions. By MYRA WOOLF. U.K. Office of Population Censuses and Surveys, Social Survey Division. London: H.M.S.O., I97I. PP. x+I53. f170

This report is based upon the results of a sample enquiry carried out in England and Wales in I967. The enquiry involved the completion by interviewers of a lengthy questionnaire for a probability sample of married women under 45 years of age and married only once. Altogether, 6,306 interviews were obtained. Informa- tion generated by the survey itself indicates a response rate of 87-9%/ . On the basis of an examination (in Appendix A 'The sample design and sample achieved') of data from the I96I Census of England and Wales, however, Mrs Woolf concludes that, effectively, the response rate may be of the order of 77-82%.

The report is presented under seven section-headings, as follows:- (i) Introduction, (2) Family Size, (3) Patterns of Family Building, (4) The Limitations on Fecundity, (5) Fertility Differentials, (6) Predicting Ultimate Family Size, and (7) Summary and Conclu- sions; in addition, there are five appendices. Mrs. Woolf's main concern throughout, however, is to examine the possibility that numbers of children anti- cipated by women might actually provide a reliable guide to their future childbearing and, therefore, have value in making population projections. To be specific, she sets out to evaluate, in these terms, what is referred to in the report as 'the most likely number of children expected" by women.

Thus, in Section 2, data relating to a variety of 'family sizes' are considered, including, for example, numbers of children 'thought ideal' and 'wanted' by wives, and numbers 'wanted' by husbands, in various situations and circumstances. But it is total numbers of children 'expected' by women, and numbers 'expected' in the next five years, that receive most attention. And, as a

I Women who say it is 'impossible' for them to have any more children are assigned a 'most likely number of children expected' equal to the number of living children they have, plus one if they are currently pregnant. Other women, depending on whether they say they do or do not 'expect' more children, and depending on how 'sure' they are about the number they 'expect', are assigned a 'most likely number' which may be the actual number of children they say they 'expect alto- gether', the mean of the 'smallest' and the 'largest' numbers they think they might have altogether, or (just as in the case of women for whom more children are an 'impossibility') the number of living children they have, plus one if they are currently pregnant.

result of her examination of these data, Mrs Woolf comes to feel that, for women on average, anyway, rather than as individuals, 'the most likely number of children expected' at least looks promising as a possible indicator of future childbearing.

Data on the spacing of births (in Section 3) and data relating to fecundity and the practice of family limita- tion (in Section 4) are examined to see whether they 'support' the 'expectations' expressed. For example, given that 'the mean most likely number of children expected' by women married in the I960's is less (2-5) than for those married in the I950's (2 7), it is of interest whether there are also differences between these groups in the observed rates of family-formation (the spacing data) and in their capacity to control their childbearing (the data on the practice of family limitation). All in all, a considerable variety of such data are examined in Sections 3 and 4 of the report. On balance, in Mrs Woolf's view, they suggest that 'the most likely number of children expected' is likely to be a good indicator of future childbearing.

The final stage in the assessment of the predictive value of the 'expectations' women report, involves com- paring them directly with 'ultimate family sizes' estima- ted on the basis of the results of a discriminant analysis. Fundamentally, the procedure is as follows: A model is established, using data for women married in the I950's who 'expect no more children', whereby ultimate family size is 'predicted' from a set of demographic, socio- economic and attitudinal characteristics; this model is then used to generate 'ultimate family sizes' for women married in the I960's who 'expect children in the future' and these are compared with the 'most likely numbers of children expected' derived from women's statements.

The discriminant analysis is carried out only on a sub-set of the women married in the I950's who 'expect no more children', namely, those married between their 20th and 25th birthdays, who are themselves non- Catholic, and whose husbands are non-Catholic. And not one but two such analyses are carried out, women married in the period I950-54 and those married during I955-59 being dealt with separately. Altogether, I3 variables are included.

The discriminant analysis is directed at the 'predic- tion', using these I3 variables, of ultimate family size classified, first, in four categories i.e. o or I, 2, 3, 4 or more, and then in two categories i.e. 2 or fewer, 3 or more. In the former case, the best results obtainable are

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334 BOOK REVIEWS

those where, for the I950-54 and I955-59 marriage- cohorts respectively, 5i and 49"0 of the 'predictions' are incorrect; in the latter case the best results obtainable are those where, for both marriage-cohorts, 29%h are incorrect.

Using the results of the discriminant analysis carried out on the I955-1959 marriage-cohort with ultimate family size classified in two categories, 'ultimate family sizes' are generated (clearly they must be either '2 or fewer' or '3 or more') for women married in the I960'S between their 20th and 25th birthdays, who are (and whose husbands arc) non-Catholic, and who 'expect children in the future'. These are then compared with 'most likely numbers of children expected'.

For some 62% of the women the values generated coincide with 'most likely numbers of children expected'; about half of the remainder have a 'predicted' value of '3 or more' when the 'most likely number expected' is '2 or fewer' and, for the other half, the reverse is true. Mrs Woolf finds this result encouraging. It suggests, she believes, 'that the mean expected ultimate and mean predicted ultimate family size will be similar' (p. I I3). And she goes on to say: 'Assuming, in the absence of important changes in external conditions that might affect family size, that the 'true' mean ultimate family size will be of the order indicated by one or other of these measures, this study like the G.A.F. studies may well achieve a coincidence of expected and actual values for mean ultimate family size by the cancelling out of errors of over-expectation and underestimation by equivalent-sized groups.'

It is the reviewer's opinion that Mrs Woolf is quite wrong to draw the conclusions she does from the dis- criminant analysis exercise, and this is argued below. Several other aspects of the report are then criticised.

It is not really necessary to debate whether, if the discriminant analysis were more successful, the 'ulti- mate family sizes' generated for women married in the I960's could be regarded as a means of 'validating' 'most likely numbers of children expected' (although it is far from self-evident that they could) since, in fact, the discriminant analysis is too unsuccessful to allow useful comparisons between them. The problem derives essentially from the crudeness of the 'predicted ulti- mate family sizes' that emerge. Since 'predicted' and 'most likely expected' ultimate family sizes may agree in terms of the categories '2 or fewer' and '3 or more' and yet really be different, it is impossible to say what agreement may mean. The situation is further compli- cated by the fact that, in any case, given the discrimi- nant analysis results, a reasonable expectation is that some 30% of 'predicted ultimate family sizes' will be incorrect. Finally, and over and above all this, it should be noted that the very fact that only two categories are involved means that a measure of agreement between 'predicted' and 'most likely expected' ultimate family sizes is fairly easy to achieve; if 'ultimate family sizes' were assigned to women at random, for example, rather than on the basis of the discriminant analysis results, a 50% agreement would be anticipated. All in all, the data available just do not permit the conclusions Mrs

Woolf comes to. Despite the fact that it is clearly not possible to

arrive at a conclusive, or even a highly persuasive, assessment of the predictive value of 'expectations' using only data derived from a survey confined to a single point in time (whether or not women will, as individuals or on average, realize their expressed 'expectations' is an empirical matter), it does seem sensible to examine such data to see whether 'expectations' at least look plausible from the point of view of their possible use for predictive purposes. In attempting to do this, however, Mrs Woolf, again and again, neglects to take up the negative points that emerge. Her uncritical acceptance of the data of Table 2.11 (the reviewer is not satisfied with the comments made on page 52) is an example of this.

The basic problem with the data shown below (only a very small fraction of the data of Table 2. I I) is that there is an incompatibility between 'mean number of children expected in the next five years' and 'mean most likely number expected in the future'. If the former is taken seriously, for example, then either the latter is to be rejected, or it must be believed that these women, starting at a point five years after the survey i.e. when the youngest is 37 and most are in their 40's, will have an average of 0 21 children each. On the other hand, if 'mean most likely number of children expected in the future' is taken seriously, the 'mean number expected in the next five years' looks low. The point is not that such evidence as this necessarily means that one or other of the items in question is, in general, untrustworthy; it is simply that it ought to provoke concern and discussion and that it has not.

Women married during I950-54, with ages at marriage 20-24.

Mean number of children

Expected* Expected* Expected in Still alive in future in total next 5 years

2-30 0 28 2-58 007

*'most likely' number. Source Table 2.II pp. 26-27

An important part of what is attempted in Section 3 of the report is available, and in a much more detailed form than it is possible to obtain from an analysis of 6,306 cases, in the annual Registrar General's Statistical Review of England and Wales. Table QQ(b) of this publication shows, for women married once only, mean family sizes at each single year of marriage duration, by age at marriage (five-year age-groups) and year of marriage (individual years). This table would permit a much more detailed examination of changes in patterns of family-formation than Mrs Woolf has found possible using only the survey data, and ought to have been used.

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BOOK REVIEWS 335

The way in which data are introduced and presented in the report is, in general, unsatisfactory. Some items are not defined at all, and for others, the definitions provided are unclear. Tables are, in some cases, very poorly labelled, and non-statement is almost never indicated. There is a scattering of numerical inconsisten- cies within and between tables.

Many of the definitions provided in Appendix C ('Definitions'), for example, cannot properly be under- stood without reference to the questions actually asked, and these are not presented. Table 2.6 is headed 'Mean number of children considered ideal' when, in fact, most of the data presented stem from questions about numbers of children 'wanted'. Appendix B ('Base numbers for tables') contains several numerical in- consistencies. A comparison of Tables 2.I7 and 2.I8

(with the 2.17 total corrected from 2720 to either 2220 or 2270) suggests that the extent of non-statement in

connection with 'children wanted by wife at marriage' is not trivial; yet no mention is made of this in the report (even though, for example, it might be considered relevant to the interpretation of Table 2.6) and insuffi- cient data are available for the reader to make his own assessment. Despite the fact that the mode of construc- tion of the 'most likely number of children expected' (see footnote I) means that non-integer values are pos- sible, none appear, for example in Table 2.9(c), and no explanation is offered; nor is there any indication of whether a 'most likely number of children expected' of 2.5 would be considered '2 or fewer' or '3 or more'.

The 'Family Intentions' report is, in many ways, then, rather unsatisfactory. There are various methodological weaknesses and the mode of presentation of data is often unhelpful.

CHRISTOPHER LANGFORD - London School of Economics

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