the agricultural sector had the greatest affect on the establishedrnpopulation because, until 1930, half of the U.S. populationrnlied in rural areas. The break in farm prices in 1920, for example,rnwas followed by a fertilit}’ decline in rural America.rnMore than ten years later, urban fertility fell in response to thernGreat Depression.rnThe U.S. fertility rate was reviving by the end of World WarrnII and, in the years 1946 to 1962, recovered to levels notrnseen for decades—the fabled Baby Boom. Conditions favoredrnthe growth of a strong middle class. Specifically, by 1946,rnAmericans enjoyed a surging demand in the labor market becausernof economic growth and the limited number of men enteringrnthe labor force. (The small generation of the 1930’s, asrnwell as the G.I. Bill, which encouraged college attendance as arnnear-term alternative to employment, saw to that.) The smallrnlabor force relative to job openings created excellent entr)-levelrnopportunities and accelerated promotions, while technologicallyrndriven growth in productivity checked inflation. Immigrationrnhad virtually no impact on the labor market (except forrnthe Southwest bracero program) and was minimal until 1965.rnThe opportunity structure gradually changed, and, by 1962,rnthe Baby Boom ended. Upward mobility stalled as the employmentrnpipeline filled and the labor force grew rapidly, mostlyrnfrom Baby Boomers coming of age. Vernon Briggs observesrnthat, “In 1964, one million more people reached the age of 18rnthan the vear before and the entry number remained at thisrnhigh level unhl 1980.” Competition for entr)’-leve] positionsrnstiffened, and, while many peo]jle saw their standard of liingrnrise, progress for white Americans was significantly slower thanrnthe steamy pace that had been taken almost for granted sincernWorld War II. At the same time that inflation-adjusted incomernfailed to rise at the accustomed pace, schools became overcrowded,rnand taxes rose to pay for new schools and other infrastructure.rnAt the national leel, war launched the countr-rninto a renewed bout of deficit .spending.rnFurther developments included the 1973-74 oil embargo.rnHigher oil prices and spot shortages set off the “quiet depression,”rnwith productivit}’ and wage increases much below thosernof the previous three decades. Pushed b- infladon and recession,rnthe econom}’ fell from its historic growth trajectory ofrnthree percent per year to a modest one percent.rnIn fact, most working Americans have seen a decline in theirrnpersonal economic circumstances since about 1973; the majorityrnof working people have experienced either stagnant orrndeclining earnings measured in inflation-adjusted, after-taxrndollars. Worsening labor market conditions for blacks were initiallyrnsomewhat offset by new civil rights and welfare assistance.rnBy the 1990’s, however, the impact of these programs had wornrnthin, because an accustomed ]eel of opportunity is not perceivedrnas parficularly good, and, in fact, most blacks are amongrnthe 80 percent of Americans whose real income has not appreciablyrnincreased for 25 years.rnNot all sectors of American societ) participated equally inrnthe periods of economic growth after 1980. Only the top 20rnpercent of families, and especially the upper five percent, madernsignificant income gains; the middle class fell into decline.rnIn many families, both spouses work in order to maintain accustomedrnamenihes and educational opportimihes for children.rnFew young couples belie e that their children, if they arernto receive necessary parental attention and educational advantages,rncan have as many brothers, sisters, and cousins as theyrnthemseK’cs had. Small wonder that the average age of marriagernhas risen, and that family size has declined.rnWomen and couples delay marriage and are cautious aboutrnexpanding their family if the’ think that their personal economicrnprospects are narrowing compared to a reference standardrn(their own parents’ lifest)’le, for example). Just as thernGreat Depression made many people wary of childbearing,rneconomic conditions beginning in the mid-I970’s depressedrnfamily size in most sectors of American society.rnPersuaded by the history of fluctuations in the fertility rate,rnthe Advisory Council on Social Securitx- has adopted a similarrntheop.’. Their 1994-1995 Report argues that a small birth cohort,rnwhose members encounter ample job opportunities relativernto their number, will command high wages, see rapid careerrnadancement, and, therefore, have big families. On thernother hand, a large birth cohort tends to flood the labor market,rnresulting in stagnant or falling wages and benefits and a declinernin desired family size. Notably, the Advisory Council not onlyrnaccepts the principle that perceived opportunity is a determinantrnof the fertility rate, but also assumes that rapid populationrngrowth depresses the earnings of the average working person.rnFew young couples believe thatrntheir children, if they are tornreceive necessary parental attentionrnand educational advantages, can havernas many brothers, sisters, and cousinsrnas they themselves had. Small wonderrnthat the average age of marriage hasrnrisen, and that family size hasrndeclined.rnIn feet, it is well documented that a change in the size of thernlabor force, all else being equal, affects wages. Ronald Lee, examiningrnpre-industrial England, and Claudia Goldin, reportingrnon early 20th-century labor markets in cities heavily impactedrnby immigration, find that an increasing labor supplyrndepresses both wages and conditions of work. The converse isrnalso true: Economic growth combined with the relatively smallrnlabor force after World War II raised compensation, prospectsrnfor promotion, and family size.rnThe predictive value of the 1994-1995 Report of the AdvisoryrnCouncil on Social Security is weakened, imfortunately, byrnfailure to take into account the labor market effects of immigration.rnIndeed, as the example of Concord, Massachusetts,rnshows, these exogenous flows of labor may smooth out the na-rn14/CHRONICLESrnrnrn