For example, since we know that period effects and age effects (see below) are zero for children 13 and older, we can infer from figure 1 that there has been a sizeable cohort trend
in girls' enrolment, which may have resulted in higher likelihood of later cohorts to be enrolled.
1960-80 1960-1980 1%: No age controls, region x cohort -0.036 -0.072 4,792 (0.004) (0.025) 1960 1%, 1970 2%, and 1980 5%: No age controls, region x cohort -0.045 -0.045 4,797 (0.004) (0.024) With age cubic, region x cohort -0.039 -0.047 4,797 (0.004) (0.024) With age cubic x Census year, -0.040 -0.047 4,797 region x cohort (0.004) (0.024) With age cubic x Census year, -0.048 -0.016 4,797 state x cohort trend
(0.004) (0.024) B.1960-2000 1960 1%, 1970 2%, and 1980-2000 5%: With age cubic x Census year -0.034 -0.026 8,636 (0.003) (0.015) With age cubic x Census year, -0.036 -0.012 8,636 state x cohort trend
(0.003) (0.016) C.
As before, [H.sub.jt] stands, in turn, for average weekly hours, average annual weeks, and average annual hours of market work of women in age group j in survey year t, and [Mathematical Expression Omitted] is a cohort trend
. The estimates of b measure the annual percentage change in the dependent variable, and these are reported in Table 18 when annual hours constitute the dependent variable.
The estimated cohort trends
for Models 1 and 3, reproduced in Table 7, show that controlling for education and enrollment dramatically reduces the estimated cohort trend
where [C.sup.T.sub.t] represents a cohort trend
, Gt is the proportionate change in real GNP, [Z.sub.jt] is the cohort size variable described above, and [W.sub.jt] is average real hourly earnings for experience group j in calendar year t.
* Data should be analyzed for individual and cohort trends
. On an individual level, data scientists can begin to identify what makes a person most likely to engage in violence, while on a group level, we can begin to spot trends in project efficacy based on specific parameters.
* Our approach is inspired by that of a similar analysis, which found that the proportion of births that occurred outside of marriage increased to a greater degree than the proportion of women who had a nonmarital birth (source: Hoffman SD and Foster EM, Nonmarital births and single mothers: cohort trends
in the dynamics of nonmarital childbearing, History of the Family, 1997, 2(3):255-275).
in the age of initiation of drug use in Australia.
The respondent data on marital, family, and career echoes the civilian cohort trends
only for the last cohort.
To demonstrate how age group, period, and cohort membership influenced generalized social spending orientations, we present a simple tabular presentation of age, period, and cohort trends
for the three spending domains (see Alwin 2003; Alwin and Scott 1996).
Although it is impossible to conjecture with any certainty about future levels of fertility, projections can be made based on past cross-sectional and cohort trends