Income, Labor Supply, and Urban Residence
指出，已婚女性劳动参与率随丈夫收入增加而显著下降，这一因素导致中低收入家庭因更多成员工作而更靠近市中心，从而解释了为何收入与居住距离的关系在实证中较弱。
The framework for urban spatial models as developed in the last twenty years contains two main features: access and bid rent. In a recent article in this Review, William Wheaton (1977b) done serious damage to this framework by concluding that the long-run spatial equilibrium theory derived from bid rent contributes little to the explanation of American location-income patterns (p. 631). He finds that the theory developed by William Alonso, Richard Muth, and others produces a very weak tendency for middleand upper-income families to live at a greater distance than poor families from the central business district (CBD). The purpose of this note is to argue that the Alonso-Muth theory is an important tool in understanding urban structure if account is taken of one previously ignored factor-that the labor force participation of married women varies dramatically and inversely with the income of their husbands. Middleand lowerincome households have more of their members in the labor force, and this pulls these groups closer to the CBD. Muth and Wheaton have noted that there is only a weak relationship empirically between median family income and distance from the CBD. Muth (p. 263) found that income did not increase with distance on the South Side of Chicago when the age of the housing stock was included in the regression. This gives more support to the filtering model of urban structure than to Muth's analysis.' Wheaton (1977b) finds that bid-rent schedules decrease very little in slope as income increases, thus producing a very weak tendency for higher income households to live farther out. The models underlying the analyses of Wheaton and Muth rely on the simplifying assumption of a one-worker household. A caveat is usually stated regarding the effect of multiple-worker households (see Muth, p. 41; Wheaton, 1977a, p. 206). Others have looked at the two-worker household but have not made the connection between working wives and husbands' incomes (see Walter Oi; Michelle White; Oded Hochman and Haim Ofek), although this connection was noted some time ago in the labor economics literature (see Glen Cain). The fact that wives' labor supply is a major factor in the urban labor force is illustrated by Table 1. The participation rates of married women, husband present, decline with husband's income in almost every category, except the numerically unimportant case of husbands who earned under $3,000. In most categories the rates at the $3,000-6,000 level are double or more the rates for the over $15,000 level. However, participation rates also differ quite a bit by age, both because of life cycle effects such as schooling and childbearing, and because of the pronounced time trend of wives' participation, shown in Table 2. Younger labor force members have made different decisions regarding careers and investment in human capital, which argues for treating them separately from older workers. The participation of married women in the labor force been increasing steadily for about a century. This coincides with Wheaton's observation on the timing of the movement of upper-income groups to the suburbs, which, he says, has been evolving gradually ever since the streetcar suburbs of the late nineteenth century (1977b, p. 620). Thus the changing characteristics of the labor force have accompanied the changing location of households by income. *Boston College. I received a great deal of helpful criticism on this paper from Christine Hekman, Marvin Kraus, John Meyer, and Joseph Quinn. Financial support for this research was provided by the HarvardM.I.T. Joint Center for Urban Studies. 'I am indebted to John Meyer for valuable help in pointing out some of the implications of Muth's empirical results.