Papers by Kenneth C . Land
We analyze the association between self-reported arthritis and mortality in the U.S. elderly disa... more We analyze the association between self-reported arthritis and mortality in the U.S. elderly disabled and non-disabled individuals using unique disability-focused data from the large-scale population-based National Long Term Care Survey. Males and females who reported arthritis/rheumatism have about 20% smaller risks of death than those who did not report those conditions. This inverse relationship is even more pronounced in disabled individuals. For females, this effect is age insensitive, while for males it is limited to ages below 85. Demographic and 19 major geriatric conditions have trivial effect on these risks supporting the view that a better survival of diseased individuals can be attributed to the effects of medical treatment. Given the widespread prevalence of arthritis/rheumatism and disability in elderly populations in the world and the increasing population of the elderly, these findings call for comprehensive analyzes of factors driving better survival and medical cos...
Handbooks of Sociology and Social Research, 2019
Mathematical demography is the subfield of demography that is concerned with developing and refin... more Mathematical demography is the subfield of demography that is concerned with developing and refining measures and methods for studying population composition and change. Historically, demographers used population level data to compute measures of the key components of population change: fertility, mortality, and migration. However, the field has expanded considerably over the last half century to include predictors and consequences of demographic change. Sample data is now commonly used by demographers, and statistical methods are commonly used in conjunction with mathematical methods. In this chapter, we define key mathematical concepts that form the basis for historical and contemporary demographic analyses, including the population balancing equation and rates. We discuss the single decrement life table and its extensions to multiple decrements and multiple living states. Next, we discuss the stationary population theory that underlies life table computations and show its extensi...
Demography of aging is a subfield of demography that focuses on the older members of a population... more Demography of aging is a subfield of demography that focuses on the older members of a population as well as the processes and consequences of population aging. Research in the demography of aging examines a number of topics, including the state and status of the older population, changes in the numbers, proportionate size, and composition of the older population, demographic forces of fertility, mortality, and migration that bring about these changes, and the effects of these changes on the social, economic, health, and personal well-being of the elderly. Major factors associated with population aging are reviewed.
Communications in Statistics - Theory and Methods, 2017
surveys in grouped and right-censored categories, there is a lack of statistical methods simultan... more surveys in grouped and right-censored categories, there is a lack of statistical methods simultaneously taking both grouping and right-censoring into account. In this research, we propose a new generalized Poisson-multinomial mixture approach to model grouped and rightcensored (GRC) count data. Based on a mixed Poisson-multinomial process for conceptualizing grouped and right-censored count data, we prove that the new maximum-likelihood estimator (MLE-GRC) is consistent and asymptotically normally distributed for both Poisson and zeroinflated Poisson models. The use of the MLE-GRC, implemented in an R function, is illustrated by both statistical simulation and empirical examples. This research provides a tool for epidemiologists to estimate incidence from grouped and right-censored count data and lays a foundation for regression analyses of such data structure.
The Springer Series on Demographic Methods and Population Analysis, 2016
The use of general descriptive names, registered names, trademarks, service marks, etc. in this p... more The use of general descriptive names, registered names, trademarks, service marks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. The publisher, the authors and the editors are safe to assume that the advice and information in this book are believed to be true and accurate at the date of publication. Neither the publisher nor the authors or the editors give a warranty, express or implied, with respect to the material contained herein or for any errors or omissions that may have been made.
Social Psychological and Personality Science, 2017
Twenge, Sherman, and Lyubomirsky (TSL) claim that long-term cultural changes have increased young... more Twenge, Sherman, and Lyubomirsky (TSL) claim that long-term cultural changes have increased young adults’ happiness while reducing mature adults’ happiness. To establish their conclusion, TSL use trend analyses, as well as more sophisticated mixed-effects models, but their analyses are problematic. In particular, TSL’s trend analyses ignore a crucial cohort effect: well-known lower happiness among baby boomers. Furthermore, their data aggregation obscures the ephemerality of a recent period effect: the Great Recession. Finally, TSL overlook a key finding of their mixed-effects models that both pre- and post-Boomer cohorts became happier as they aged from young to mature adults. Our reanalyses of the data establish that the Baby Boomer cohort, the short-lived Great Recession, and unfortunate data aggregation account for TSL’s results. The well-established, long-term relationship between age and happiness remains as it has been for decades despite any cultural shifts that may have occ...
Homicide Studies, 2017
We examine the empirical applicability of differential institutional engagement in explaining the... more We examine the empirical applicability of differential institutional engagement in explaining the youth age structure effect on neighborhood homicide. Using the National Neighborhood Crime Study and Census data, we conduct a multilevel spatial analysis of homicides in 8,307 census tracts. We find support for three indicators of differential institutional engagement (disengaged youth, educational engagement, employment engagement). An additional dimension of institutional engagement (familial engagement) operates in the expected direction but is not statistically significant. We argue that previous cross-sectional studies reporting a null or negative relationship between percentage of young and homicide are due to omitting measures of institutional youth (dis)engagement.
Population Research and Policy Review, 2015
This paper investigates historical changes in both single-year-of-age adult mortality rates and v... more This paper investigates historical changes in both single-year-of-age adult mortality rates and variation of the single-year mortality rates around expected values within age intervals over the past two centuries in 15 developed countries. We apply an integrated hierarchical age-period-cohort-variance function regression model to data from the human mortality database. We find increasing variation of the single-year rates within broader age intervals over the life course for all countries, but the increasing variation slows down at age 90 and then increases again after age 100 for some countries; the variation significantly declined across cohorts born after the early 20th century; and the variation continuously declined over much of the last two centuries but has substantially increased since 1980. Our further analysis finds the recent increases in mortality variation are not due to increasing proportions of older adults in the population, trends in mortality rates, or disproportionate delays in deaths from degenerative and man-made diseases, but rather due to increasing variations in young and middle-age adults.
Annals of Epidemiology
This book contains information obtained from authentic and highly regarded sources. Reasonable ef... more This book contains information obtained from authentic and highly regarded sources. Reasonable efforts have been made to publish reliable data and information, but the author and publisher cannot assume responsibility for the validity of all materials or the consequences of their use. The authors and publishers have attempted to trace the copyright holders of all material reproduced in this publication and apologize to copyright holders if permission to publish in this form has not been obtained. If any copyright material has not been acknowledged please write and let us know so we may rectify in any future reprint. The Open Access version of this book, available at www.taylorfrancis.com, has been made available under a Creative Commons Attribution-Non Commercial-No Derivatives 4.0 license.
Chapman & Hall/CRC Interdisciplinary Statistics Series, 2013
This book contains information obtained from authentic and highly regarded sources. Reasonable ef... more This book contains information obtained from authentic and highly regarded sources. Reasonable efforts have been made to publish reliable data and information, but the author and publisher cannot assume responsibility for the validity of all materials or the consequences of their use. The authors and publishers have attempted to trace the copyright holders of all material reproduced in this publication and apologize to copyright holders if permission to publish in this form has not been obtained. If any copyright material has not been acknowledged please write and let us know so we may rectify in any future reprint. The Open Access version of this book, available at www.taylorfrancis.com, has been made available under a Creative Commons Attribution-Non Commercial-No Derivatives 4.0 license.
Physics of life reviews, 2012
A better understanding of processes and mechanisms linking human aging with changes in health sta... more A better understanding of processes and mechanisms linking human aging with changes in health status and survival requires methods capable of analyzing new data that take into account knowledge about these processes accumulated in the field. In this paper, we describe an approach to analyses of longitudinal data based on the use of stochastic process models of human aging, health, and longevity which allows for incorporating state of the art advances in aging research into the model structure. In particular, the model incorporates the notions of resistance to stresses, adaptive capacity, and "optimal" (normal) physiological states. To capture the effects of exposure to persistent external disturbances, the notions of allostatic adaptation and allostatic load are introduced. These notions facilitate the description and explanation of deviations of individuals' physiological indices from their normal states, which increase the chances of disease development and death. Th...
Multidimensional Mathematical Demography, 1982
Research Reports, which record research conducted at IIASA, are independently reviewed before pub... more Research Reports, which record research conducted at IIASA, are independently reviewed before publication. However, the views and opinions they express are not necessarily those of the Institute or the National Member Organizations that support it. Reprinted with permission from Kenneth C. Land and Andrei Rogers, editors, Multidimensional Mathematical Demography. New York: Academic Press, 1982 (ISBN 0-12-435640-0), pages 1-41.
This new series focuses on the subject of measurements and indicators of children's well being an... more This new series focuses on the subject of measurements and indicators of children's well being and their usage, within multiple domains and in diverse cultures. More speci fi cally, the series seeks to present measures and data resources, analysis of data, exploration of theoretical issues, and information about the status of children, as well as the implementation of this information in policy and practice. By doing so it aims to explore how child indicators can be used to improve the development and the well being of children. With an international perspective the series will provide a unique applied perspective, by bringing in a variety of analytical models, varied perspectives, and a variety of social policy regimes. Children's Well-Being: Indicators and Research will be unique and exclusive in the fi eld of measures and indicators of children's lives and will be a source of high quality, policy impact and rigorous scienti fi c papers.
Sociological Methodology, 2004
Age-period-cohort (APC) accounting models have long been objects of attention in statistical stud... more Age-period-cohort (APC) accounting models have long been objects of attention in statistical studies of human populations. It is well known that the identification problem created by the linear dependency of age, period, and cohort (Period = Age + Cohort or P = A + C) presents a major methodological challenge to APC analysis, a problem that has been widely addressed in demography, epidemiology, and statistics. This paper compares parameter estimates and model fit statistics produced by two solutions to the identification problem in age-period-cohort models—namely, the conventional demographic approach of constrained generalized linear models (Fienberg and Mason 1978, 1985; Mason and Smith 1985) and the intrinsic estimator method recently developed by Fu (2000; Knight and Fu 2000; Fu, Hall, and Rohan 2004). We report empirical analyses of applications of these two methods to population data on U.S. female mortality rates. Comparisons of parameter estimates suggest that both constrain...
Social Forces, 2013
In recently developed hierarchical age-period-cohort (HAPC) models, inferential questions arise: ... more In recently developed hierarchical age-period-cohort (HAPC) models, inferential questions arise: How can one assess or judge the significance of estimates of individual cohort and period effects in such models? And how does one assess the overall statistical significance of the cohort and/or the period effects? Beyond statistical significance is the question of substantive significance. This paper addresses these questions. In the context of empirical applications of linear and generalized linear mixed-model specifications of HAPC models using data on verbal test scores and voter turnout in U.S. presidential elections, respectively, we describe a two-step approach and a set of guidelines for assessing statistical significance. The guidelines include assessments of patterns of effects and statistical tests both for the effects of individual cohorts and time periods as well as for entire sets of cohorts and periods. The empirical applications show strong evidence that trends in verbal test scores are primarily cohort driven, while voter turnout is primarily a period phenomenon. Social scientists often study time-specific phenomena for which there may be age, period, and/or cohort effects. Because age-period-cohort (APC) analysis has the capacity to depict the entire complex of social, historical, and environmental factors that shape individual life courses parsimoniously, it is important for constructing and refining theories of social change. One common goal of such analysis is to distinguish the unique effects associated with age, period, and cohort . Attempts to estimate these effects, however, must address the model identification problem that occurs due to the exact linear dependency between the three variables: cohort = period -age. Thus, one cannot separately estimate them using conventional linear regression models without adding
Rejuvenation Research, 2008
Major musculoskeletal conditions including arthritis represent an increasing burden on individual... more Major musculoskeletal conditions including arthritis represent an increasing burden on individuals and societies. We analyze the association between self-reported arthritis and mortality in the U.S. elderly disabled and non-disabled individuals using unique disability-focused data from the largescale population-based National Long Term Care Survey. It is found that males and females who reported arthritis/rheumatism have, generally, smaller risks of death than those who did not report those conditions. This inverse relationship is more pronounced in disabled individuals. This finding holds for both short-(Relative Risk [RR]=0.81; 95% Confidence Interval [CI]:0.75-0.88 for males and RR=0.76; CI:0.71-0.82 for females) and long-(RR=0.82; CI:0.78-0.87 for males and RR=0.83; CI:0.79-0.87 for females) term follow-ups. For females, this effect is age insensitive, while for males it is limited to ages below 85. Demographic and 19 major geriatric conditions have trivial effect on these risks supporting the view that a better survival of diseased individuals can be attributed to the effects of medical treatment. Given the widespread prevalence of arthritis/rheumatism and disability in elderly populations and the increasing population of the elderly, these findings call for comprehensive analyses of factors driving better survival and medical costs associated with extended lives.
Demography, 1969
A basic assumption of the Cornell Mobility Model insofar as it is relevant to inter-community mig... more A basic assumption of the Cornell Mobility Model insofar as it is relevant to inter-community migration is that an individual’s propensity to move is a function of, among other things, his length of residence in the community. Parameters of the functional relationship of migration probabilities to duration status are estimated from migration histories for a sample of residents in Monterrey, Mexico, and compared with estimates reported by P. A. Morrison using data from Amsterdam, The Netherlands. In both data sets a negative nonlinear relation of the probability of migrating to duration status, as well as an interaction between age and duration status, is found. Values of parameters describing the relation within age groups differ sufficiently between the two data sets, however, to suggest that further specification of conditions under which a particular form of functional relation will obtain is necessary if the model is to be useful in migration research.
Demography, 1983
This paper applies methods of seasonal ARIMA time series analysis to U. S. monthly birth and deat... more This paper applies methods of seasonal ARIMA time series analysis to U. S. monthly birth and death rates for January 1950–December 1978. For model selection, the conventional Box-Jenkins (1970, 1976) diagnostic checks are used in conjunction with some suggestions of Nerlove et al. (1979). This results in final models that contain significant second-order autoregressive components, as well as seasonal moving-average components, for both series. In addition, some evidence is found in the birth rate series for weekly periodicities. These findings imply the existence of a seasonal adjustment procedure that improves on the Census X-11 program currently used by vital statistics agencies.
Demography, 2013
It is our pleasure to respond to the Editor's request for a commentary on Luo's article (this iss... more It is our pleasure to respond to the Editor's request for a commentary on Luo's article (this issue), which critically evaluates the utility of the intrinsic estimator (IE) that we first introduced to demography and sociology in . We first respond to the Editor's request for "an assessment of the author's argument, evidence, and conclusions." It is truly unfortunate and fundamentally incorrect to interpret our stance on the IE method as seeing it a "holy grail" or "magic bullet" for the identification problem of the age-period-cohort (APC) accounting model/multiple classification model. Nowhere in our previous publications did we make such a claim. We were crystal clear about the circumstances in which a full-blown APC model should be used. And such circumstances equally apply to any estimator of full three-factor APC models, not just the IE. Luo completely lost sight of this starting point. Works as early as Yang ( ) and as recent as Yang and Land (2013: chapter 5) have laid out a three-step procedure that should be thoroughly applied to APC analysis using the accounting model. It is so important that we believe it is worth repeating here. Step 1 is to conduct descriptive data analyses using graphics, with the objective being to provide qualitative understanding of patterns of temporal variations. Step 2 is model fitting and calculation of model fit statistics, such as the Bayesian information criterion (BIC). The objective is to ascertain whether the data are sufficiently well described by any single-factor or two-factor model of age (A), time period (P), and cohort (C) effects for which there is no identification problem. Only when these analyses suggest that all three dimensions are operative should one proceed with Step 3: a three-factor APC model to which a constrained estimator can be applied to identify the A, P, and C effects.
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Papers by Kenneth C . Land