Sibsize and the Educational Process

At what point, or points, in the process of acquiring an education does sibsize intervene most importantly? Because of free schooling and compulsory education in the United States, one might think that the dilution of family resources resulting from many children would make little difference to educational attainment through high school but that, after high school, sibsize would be a major determinant of who would go to college. Actually, our results are quite different from commonsense expectations. Sibsize has a major

Figure 2.2.
Total Years of Education (Adjusted Means) by Sibsize, White Men
and Women Age 25 and Over, Various Surveys.

effect on educational attainment even during graded schooling (grades 1 through 12). In fact, as we shall see, in most studies attainment is more highly correlated with sibsize at the graded level of schooling than at the postsecondary level.

Consequently, another aspect of the importance of sibsize for educational attainment is that it has exerted its effects early in the schooling process. It has operated to select out a high proportion of students prior to high school graduation, thereby cutting them off from further academic advancement. This finding suggests that sibsize operates not simply by diluting parental economic resources for postsecondary schooling, but by impinging on basic education at the graded level in a manner that includes both economic and noneconomic effects.^[2]

Years of Graded Schooling

Figure 2.3 shows, for all of the adult studies, the adjusted means for total years of graded schooling by sibsize (see also appendix table B.3). As between sibsize one and sibsize seven-plus, it is typical for respondents to have lost about a year or more of graded schooling even after taking account of family background. In judging the importance of such a deficit (all other factors in our analysis controlled), we must bear in mind that the loss of a year of graded schooling inevitably translates into large proportionate decrements in high school graduation. Hence, the loss of a year of graded schooling, on average, can be judged as very significant because of the great marginal importance of completing the last year of high school. We shall consider this next.

Proportions Graduating from High School

Figure 2.4 shows the adjusted percentages graduating from high school according to sibsize (see also appendix B, table B.4). Despite the theoretical importance of the background variables for which we have adjusted, it is clear that the sibsize differences in high school graduation remain large. Singleton boys are nearly half again as likely to graduate from high school as boys from families of seven children or more, and singleton girls are about half again as likely to do so as girls from families of seven children or more.

Figure 2.3.
Years of Graded Schooling (Adjusted Means) by Sibsize,
White Men and Women Age 20 and Over, Various Surveys.

Figure 2.4.
Percentage Who Graduated from High School (Adjusted Means) by
Sibsize, White Men and Women Age 20 and Over, Various Surveys.

The percentage point differences in high school graduation between sibsize one and sibsize seven-plus, and between sibsize two and sibsize four-plus, are summarized in table 2.4.

These data thus strongly reinforce the finding that total educational differentials by sibsize do not simply reflect relative advantage and disadvantage after high school graduation. Even in the graded schooling years, and with major parental background variables controlled, increasing sibsize has deleterious consequences for educational attainment.

In a later chapter we will document in detail the intense and early school dropout levels of men from large families. If the precocity of this school leaving seems strange to some readers, they should refer to an article by Suter that deals with part of the process by which such early school leaving comes about (Suter 1980). As Suter makes clear, the major reason historically so many men in the United States did not finish high school was because they fell behind (were "left back") early on—often in grade school. Even after the advent of compulsory schooling to ages 15–16 (depending on the state), such men did not simply drop out of high school, they dropped out of lower grades in which they had remained until the school-leaving age came around.

Postsecondary Education

Among the selected population of high school graduates, we see in figure 2.5 (and appendix B, table B.5) that attendance at college (percentage of high school graduates who went to college) is also influenced by sibsize (background factors controlled). Interestingly, however, among large sibsizes in particular (sibsizes six versus seven-plus), there is less difference than there is for proportions graduating from high school. This suggests that, among these large sibsizes, the high school selection left a population of "survivors" who had about equal chances of getting to college—in effect, that the differences in life chances between being from a six-child or a seven-plus–child family had already been taken into account at the high school level. We may also note that female-only children appear to be uniformly advantaged relative to females from other sibsizes in all of the surveys when it comes to going to college. This advantage does not persist, however, for years of college schooling (fig. 2.6).

If people have managed to enter college, does sibsize affect the number of years of college schooling they have been able to achieve? Figure 2.6 (appendix B, table B.6), for respondents and their wives in OCG 1962 and 1973, shows that the effects of sibsize are relatively small for this select group. That these effects exist at all, given the process of prior selection by sibsize that we have witnessed, is quite remarkable.

Figure 2.5.
Percentage of High School Graduates Who Went to College (Adjusted Means)
by Sibsize, White Men and Women Age 25 and Over, Various Surveys.

Figure 2.6.
Years of College Schooling among Those Who Went to College (Adjusted Means)
by Sibsize, White Men and Women Age 25 and Over, Various Surveys.

The Relative Effects of Sibsize on Graded and Secondary Education

Our results so far, using multiple classification analysis, suggest that as the level of schooling rises the effect of number of siblings decreases. The truth of this is most succinctly exemplified by the unstandardized regression coefficients (slopes) for sibsize at each educational level. These are shown in table 2.5. From this table we see that the effect of sibsize diminishes with each level of schooling, the greatest effect being at the graded-schooling level. We have suggested that the selection against large families that occurs so early in the educational process is probably due to two factors: (1) outright school leaving (dropping out) among those from large families, and (2) being "left back" in high proportions among those from large families until dropping-out occurs at a legally permissible age. Here we may note for the first but not the last time, that this selection has important methodological implications for all research on the "effects" of number of siblings among juniors and seniors in high school, or among college populations. Such populations will have been already strongly selected by number of siblings at an earlier stage in the educational process.

The Importance of Sibsize Relative to Other Family Background Variables

In our introductory chapter, we pointed out that the effects of sibsize, relative to the effects of other family background variables, have tended to be understated by students of social stratification, who investigate the consequences of family background for educational opportunity.

One reason for investigators' underestimating the relative importance of number of siblings is that the influence of this variable is often incorporated into the overall influence of family background or "home" effects (so-called ascriptive influences) versus the respondent's own characteristics and performance (viewed as meritocratic). Thus absorbed into family background, number of siblings serves to overestimate the importance of parental "SES" and turn attention away from sibsize as an independent influence. For example, the following quotation from Alexander and Eckland is fairly typical of discussion of even those studies that have specifi-

cally included number of siblings as a predictor (Alexander and Eckland 1980, 34).

More recent research, in revealing the range of advantages and liabilities conferred by the family of origin, serves only to broaden and deepen our appreciation of the residue of ascription in the supposed meritocracy (Blau and Duncan, 1967; Duncan, Featherman and Duncan, 1972; Hauser and Featherman, 1977).

To what is this persistent importance of the family attributed? Largely, it appears, to the simple fact that children from high SES families tend to go further through school than their low SES counterparts, and hence reap the labor market benefits that advanced schooling accrues.

A second reason for underestimating the relative importance of number of siblings to an individual's attainment is that models of status attainment (including those used here) treat parental SES as exogenous—in no way influenced by parental reproductive behavior. Yet parental educational attainment and occupational achievement are not independent of parental age at marriage and childbearing, including number of children. Hence, to the extent that parental SES is itself influenced by numbers of children, the effect of the respondent's sibsize on measures of parents' education and occupation is not counted.

Additionally, insofar as investigators have studied the educational process among high school students (for example, the high school seniors in the Wisconsin Study, Sewell and Hauser 1980, or the National Longitudinal Study of the High School Senior Class of 1972, Eckland and Alexander 1980), the importance of number of siblings to postsecondary educational goals and attainment will appear relatively small (compared to other variables) because of the selection process by sibsize that has already taken place. Many youngsters from large families have already dropped out (or been held back) leaving a selected group of survivors from these families, whereas those from small families are less selected.

Finally, as a number of critics of the sociology of status attainment have noted (Spaeth 1976; Williams 1976; Scarr and Weinberg 1978), parental socioeconomic status is itself, in part, the translation of parental ability into socioeconomic currency. Were it possible to control for parental ability, the effect of parental SES on the

son's achievement would probably be less and an additional effect of the parental ability transmitted to the child would be added. This point, which is increasingly being addressed by economists and sociologists (see, for example, Eckland 1967; Griliches 1970; Bowles 1972; Griliches and Mason 1972; Bowles and Gintis 1974; Bowles and Nelson 1974; Taubman and Wales 1974; Welch 1974; Griffin 1976; Hauser and Daymont 1977), will be discussed in more detail in chapter 4 on number of siblings and intelligence.

Here we will examine the relative effects of sibsize and other background variables for the adults in some of our samples. Table 2.6 shows, for OCG 1962 and 1973 as well as GSS 1972–1986, the standardized regression coefficients of the principal variables in our model for each level of the respondent's educational attainment. Standardized regression coefficients express the value of variables on the same scale so that their relative importance can be judged. The reader should be reminded that data on the father's education for the wives of the men in the 1962 OCG study are not available, and for these calculations we have made the two OCG studies comparable. To our knowledge, this is the first time that the standardized coefficients for disaggregated amounts of education (using the basic educational attainment model for adults) have been presented.

Among the variables in the model, all the surveys show (table 2.6) that the father's education is the most important influence on the son's total educational attainment. In this regard, the following quotation from Hauser and Featherman's analysis of total educational attainment in the two OCG studies is worth noting (1976, 105):

We have not shown any standardized regression coefficients; some readers may be interested to know that in virtually every subpopulation we have looked at, father's education is relatively more important than any other background variable.

In both OCG 1973 and GSS 1972–1986, sibsize is second in importance and outweighs, in negative effect, the positive effect of the father's SEI (the third most important influence). In OCG 1962, sibsize is close to the father's SEI and probably would also exceed it in this study as well were it not for the anomalously high SEI (see, Hauser and Featherman 1976, 104).

Turning to the relative status of the variables in the disaggregated process of education, we find some interesting results. Among the educational levels, the relative influence of the father's education and sibsize is greatest for graded schooling, whereas the father's SEI is unimportant at this level. This finding might suggest that, given free schooling, whether the grades are completed depends more on the value placed on education by the parents and the child's ability (both native and as a consequence of socialization in the home) than on socioeconomic factors. However, the dilution of material resources is represented by sibsize at this level of schooling as is the corresponding ability of parents to sustain the direct and indirect costs of early schooling. How much the sibsize variable operates by influencing IQ and grades, and how much by influencing the direct and indirect costs of maintaining offspring in school, cannot be measured in these adult samples, since data are not available on either IQ or school performance. In later chapters, we shall see, however, that among samples of youngsters, the effects of sibsize on IQ are substantial, especially among samples of very young children. Hence, one can speculate that the early drop-out rate among men from large families was not due entirely to the diluting effect of sibsize on material resources but was due as well to sibsize effects on IQ, and the influence of the latter on school performance. It should be noted also that men whose fathers were farmers (farm background in the equations) experienced some relatively important negative effects at the graded-schooling level. Thus, although in general the father's occupational status was unimportant for graded schooling, having a father who was a farmer was a disadvantage.

Once a boy graduates from high school, table 2.6 shows that college attendance and years in college depend more on the father's SEI than on either his education or sibsize. By the college-going level, there are a number of reasons why father's SEI should move up in relative importance. One reason is that there has been a drastic selection out of school of children from larger families reducing, thereby, the relative importance of sibsize. Second, college involves not only indirect costs (the student's time and consequent loss of earnings) but usually substantial direct costs as well.

Among young women, although the father's education is not included for OCG 1962 and 1973, the patterns by educational level

of the other variables are, with two interesting exceptions, the same as for men. First, in all of the surveys, farm background has a fairly substantial positive relative effect on whether a high school graduate goes to college. This difference is evident in the unstandardized coefficients as well. We may speculate that this effect is due to the traditional emphasis in land-grant colleges on applied subjects, nursing, and school teaching. Second, the GSS 1972–1986 data, table 2.6, based on female respondents and including the father's education, suggest that whether a girl goes to college and stays in college is relatively more dependent on her father's education than on his SEI—a finding that is also evident in the unstandardized coefficients (table 2.5)—and one that is different from men. It is thus probable that increased education among fathers is important in influencing the value placed on advanced education for women.