Peter A. Morrison

Return and other sequences of migration in the United States

We examine repeat migration sequences in the United States especially those that entail a return, using data from the Panel Study of Income Dynamics. Our guiding hypotheses derive from the concepts of location-specific capital and imperfect information. Descriptive analysis elucidates the dynamics, tempo, and differential frequency of repeat migration among various socioeconomic groups. Results disclose differences among migrants who choose to return or move onward to a new location, or do not move again, and lend support to our analytical framework. Major findings are: (1) the propensity to return to an area varies directly with the amount of locationspecific capital that is left behind and inversely with the ex-resident’s length of absence, (2) which repeat migration sequence unfolds—return or onward—depends on the ex-resident’s educational level and experience of unemployment.

Chronic movers and the future redistribution of population: A longitudinal analysis

This research has two purposes. First, it examines individual- and household-level factors related to the propensity to move. The findings reveal that mobility is largely a matter of habitual movers changing residence repeatedly and frequently. The second objective is concerned with strengthening the foundation for projecting aggregate levels of mobility: (1) how does repeated movement manifest itself at the metropolitan scale? and (2) for predictive purposes, which aggregate indices capture the most important features of local population composition? Mobility rates were found to vary principally with the prevalence of chronic movers in an SMSA. These findings have several implications for policies designed to guide future population distribution. First, an SMSA’s capacity to correct local manpower imbalances by exchanging human capital with other areas may depend partially on its relative abundance of habitual movers. Second, the likelihood that new cities would attract disproportionate numbers of hypermobile persons might enhance their role within the framework of a broader distribution policy. The question posed here is whether high intrinsic levels of population turnover in some cities might fit into a larger strategy for realigning population growth and distribution nationally.

Duration of residence and prospective migration: the evaluation of a stochastic model.

ResumenEL objectivo de este trabajo es evaluar La precisión empirica del Modelo de MobiLidad Cornell. Se describe La migración. como un proceso estocástico governado por probabilidades no-estacionarias: durante un intervalo de tiempo dado, se presume que un individuo está expuesto a un riesgo de migrar, y que éste decrece a medida que él continúa viviendo en la misma comunidad. Entonces, la hipótesis principal es que la propensión de una persona a mobilizarse declina a medida que aumenta la duración de su residuencia.Una hipótesie secundaria propane que la edad interviene en esta relación. Datos longitudinales, (5,000 historias residenciales del sistema de registros de población de los Paises Bajos, fueron analizados y traducidos en probabilidades prospectivas específicas por edad y duración, Ambas hipótesis fueron verificadas. Específicamente, la rolación. es negativa, curvilinear, y varía significativamente con la edad, Para facilitar el análisis de simulación del modelo, las relaciones encontradas en los datos estan resumidas en un conjunto de ecuaciones logarítmicas de predicción.Los hallazgos de este trabajo enfatizan la limitación fundamental de los modelos de probabilidad estacionaria para describir la migración y sugieren que la alternativa no-estacionaria es una formulación. más precisa. En general, los proceeos de cambia que sólo tienen una semejanza formal con la migración, por ejemplo un cambio de nombre o de actitud, pueden ser gobernados también por un principio de estabilidad acumulativa. La evidencia justifica major investigación sobre la aplicabilidad del modelo a ostros procesos sociales en los que operan factotes de tipo inercia.SummaryThe objective of this paper is to evaluate the empirical accuracy of the Cornell mobility model. Migration is formulated as a stochastic process governed by non-stationary probabilities: during a given interval of time, an individual is presumed to undergo a risk of migrating that decreases as he continues to reside in the same community. The major hypothesis, then, is that a person’s propensity to move declines as his duration of residence increases.A secondary hypothesis proposes that age interacts with this relationship. Longitudinal data (5,000 residential histories from the Netherlands system of population registers) were analyzed and translated into prospective probabilities that are age- and duration-specific.Both hypotheses were substantiated. Specifically, the relationship is negative, curvilinear, and varies significantly by age. To facilitate simulation analysis of the model, the relationships found in the data are summarized in a set of logarithmic prediction equations.The findings of this paper underscore the fundamental limitation of stationary probability models in portraying migration and suggest that the non-stationary alternative is a more accurate formulation. More generally, processes of change which bear only a formal resemblance to migration (for example, brand switching or attitudinal change) may be governed by a principle of cumulative stability too. The evidence warrants further inquiry into the applicability of the model to other social processes where inertialike factors operate.

Using the Census Bureau’s surname list to improve estimates of race/ethnicity and associated disparities

Commercial health plans need member racial/ethnic information to address disparities, but often lack it. We incorporate the U.S. Census Bureau’s latest surname list into a previous Bayesian method that integrates surname and geocoded information to better impute self-reported race/ethnicity. We validate this approach with data from 1,921,133 enrollees of a national health plan. Overall, the new approach correlated highly with self-reported race-ethnicity (0.76), which is 19% more efficient than its predecessor (and 41% and 108% more efficient than single-source surname and address methods, respectively, P < 0.05 for all). The new approach has an overall concordance statistic (area under the Receiver Operating Curve or ROC) of 0.93. The largest improvements were in areas where prior performance was weakest (for Blacks and Asians). The new Census surname list accounts for about three-fourths of the variance explained in the new estimates. Imputing Native American and multiracial identities from surname and residence remains challenging.

Beyond Stereotypes. Who Becomes a Single Teenage Mother

The effect of low-dose combined oral contraceptives (OCs) on glucose tolerance lipid metabolism and liver functions was investigated in 166 women. 69 women were taking a combination of 1 mg norethisterone + 35 mcg ethinyl estradiol (NET/EE) 65 were taking 150 mcg levonorgestrel + 30 ug ethinyl estradiol (LNG/EE) for 12 cycles and 32 had an IUD inserted (control group). Glucose tolerance seemed to be impaired after 3 months use and those exhibiting diabetic values were excluded from the study. The serum triglycerides and total cholesterol levels were elevated and HDL-cholesterol decreased in both pill groups. The shifts were more pronounced and longer lasting in the NET/EE group. There was a positive correlation between the changes in glucose and lipid metabolism. Contrary to expectations liver enzymes and bilirubin exhibited a decrease during OC use as did total protein and albumin levels. These observations draw attention to the fact that metabolic changes are induced by combined OCs even in the lowest possible dosage. However this does not necessarily mean increased morbidity in healthy women. (authors modified) (summaries in HUN ENG)

Theoretical Issues in the Design of Population Mobility Models

This paper identifies major theoretical guidelines that emerge from recent migration research, and explores their bearing on model design. A conjunctive framework combining two phases is proposed. The first phase is a retention model based on a theory of differential perception and responsiveness; it portrays the decision to move in relation to a socially structured decision threshold. The second phase is an allocation model that portrays the aggregate process whereby a system of destinations compete with each other for shares of available outmigrants.

Surname analysis for estimating local concentration of Hispanics and Asians

Surname analysis is a potentially useful technique for identifying members of particular racial, ethnic, or language communities within a population. We review the existing state of the art for identifying persons of Hispanic or Asian origin, based on surnames distinctive of each group. We describe the logic of surname analysis, profile several available surname dictionaries, and illustrate their applications in local redistricting. Results of our ongoing validation studies suggest promising future directions for improving accuracy and broadening applications.

Demographic Factors Reshaping Ties to Family and Place

This article explores the broad topic of how the selective character of human migration and changing family circumstances may shape the intensity of local need among the future elderly. At origin, it is the healthier, better educated, and more affluent elderly who venture to migrate; and although people migrate from a broad spectrum of origins, they flow selectively to a narrow spectrum of destinations. At the same time, contemporary changes in family makeup and internal division of labor alter their capacity to care for elderly members. These demographic realities define a policy issue ripe for study. 1990 census data can reveal how the pressures of population aging will diffuse spatially, in terms of timing and intensity, and, given the complex interaction of migration selectivity and family transformation, who will be distanced from whom, and with what consequences. Scattered evidence from earlier years casts light on certain facets of this issue: (a) the ties between elderly and their children, (b) the differing configurations of migration flows generating elderly concentration in locales, and (c) the changing nature of elderly concentration in recent decades. With 1990 census data, it will be possible to extend certain findings and consider their implications for how future aging and dependency may express themselves locally.

Accounting for the educational shortfalls of mothers.

Women who become mothers at an early age complete fewer years of education than women who delay childbearing. Using data from the US National Longitudinal Study of the High School Class of 1972 on 11336 females the study examines family formation during the first 4 years after high school. 3123 women had become mothers by October 1976. The mothers especially the earlier groups ranked lower than their classmates in ability class rank and socioeconomic status. Married nonparents were close to the single nonparents in ability and class rank but a much smaller proportion of married nonparents than single nonparents were enrolled in academic programs indicating that most did not plan to go to college. The studys 2 main findings are that: 1) the effects of late-teenage parenthood on young married womens current educational status and long term educational aspirations are less severe than one might infer from comparisons of observed (unadjusted) outcomes for parents and nonparents and 2) parenthood and marriage have separate identifiable effects. The marriage effects are strong for this population of women. Preexisting differences between parents and nonparents would have led to very different educational outcomes in these 2 groups even without parenthood. Many of the effects that might be attributed to early parenthood also show up as effects of early marriage alone. This is not to say that early parenthood has no effects; the mothers do lag behind other married women in both current and expected education. The results show considerable self-selection into early marriage and early parenthood. One problem with the study is that data are limited to women who managed to get to their senior year in high school.

The Functions and Dynamics of the Migration Process

Publisher Summary This chapter discusses the functions and dynamics of migration process. Migration has served, and appears to continue to serve, as an important vehicle of social mobility in a society that is stratified predominantly along lines of achievement rather than of ascription. Immigrants and, more recently, migrants from rural areas have congregated in cities, where access to the training needed for high-wage jobs in commerce and industry afforded to them opportunities to improve their material well-being. In this way, social status came to rest more on personal achievement and less on a legacy of disadvantage imposed by racial or cultural prejudice. The combination of high fertility and shrinking labor demand in rural areas led to increasing unemployment and underemployment. Therefore, many people were drawn to urban centers, attracted by both jobs and the amenities of urban life heard about through relatives, friends, and, increasingly, the mass media. Migration promotes economic efficiency by rearranging workers so as to increase national output. In economically expanding localities, migration responds vigorously to the demand for labor and has a multiplicative effect on this growth. In declining localities, it reduces imbalance between labor supply and demand in the near term, although, its effectiveness diminishes with prolonged heavy outflow.