Longitudinal data occur frequently in medical studies and covariates measured by error are typical features of such data. Generalized linear mixed models (GLMMs) are commonly used to analyse longitudinal data. It is typically assumed that the random effects covariance matrix is constant across the subject (and among subjects) in these models. In many situations, however, this correlation structure may differ among subjects and ignoring this heterogeneity can cause the biased estimates of model parameters. In this thesis, following Lee et al. (2012), we propose an approach to properly model the random effects covariance matrix based on covariates in the class of GLMMs where we also have covariates measured by error. The resulting parameters from this decomposition have a sensible interpretation and can easily be modelled without the concern of positive definiteness of the resulting estimator. The performance of the proposed approach is evaluated through simulation studies which show that the proposed method performs very well in terms biases and mean square errors as well as coverage rates. The proposed method is also analysed using a data from Manitoba Follow-up Study. / February 2017

This thesis consists of four self-contained essays in the sociology of educational stratification. Study I draws on newly collected survey data to assess the biases that arise in estimating socioeconomic differences in achievement when relying on parent and student reported data on social background. The main finding is that student reports on parental occupation overcome both the problem of misreporting that plagues other data collected from children, and the equally damaging problem of selective nonresponse among parents. Conditional estimates of ethnic disparities are relatively unaffected by these issues. Study II deals with student survey reports on the number of books in the home. A prominent string of authors has favoured this variable as a social background proxy over parental occupation or education based on its strong associations with educational outcomes. The paper applies various methods to large-scale student assessment data to show that these associations rest not on higher reliability as commonly assumed, but rather on two types of endogeneity. Low achievers accumulate less books and are also prone to underestimate their number. Study III uses survey and register data to study immigrant parents' education and its associations with children's achievement in recent Swedish cohorts. Two aspects of parental education are distinguished: the absolute years of schooling and a relative place in the source country's educational distribution. Parents' absolute education turns out to predict children's test scores and grades, whereas relative education is a better predictor of their educational aspirations. The result is of some consequence for studies seeking to assess ethnic disparities net of observed parental characteristics. Study IV extends the positional approach of Study III to understand immigrants' self-perceived social status and income satisfaction in European countries. Those higher educated by origin country than host country standards make more dismal assessments of their current situation than do other immigrants in otherwise similar circumstances. This is attributed to a social contrast mechanism and argued to be of relevance in understanding longer-term patterns of social and economic integration, including educational decisions made by the second generation. / Avhandlingen består av fyra fristående studier som alla berör utbildning och social stratifiering. Studie I undersöker med nyinsamlade enkätdata hur sociala skillnader i skolprestation riskerar att felskattas med bakgrundsuppgifter inhämtade från föräldrar respektive elever. Den viktigaste slutsatsen är att elevuppgifter om föräldrars yrke undviker mycket av den felrapportering som behäftar andra elevsvar, liksom det utbredda problemet med selektivt bortfall bland föräldrar. Villkorliga skattningar av etniska skillnader är relativt opåverkade av dessa metodproblem. Studie II granskar elevers uppgifter om antalet böcker i hemmet. En betydande litteratur har förespråkat denna variabel som ett mått på klasstillhörighet framför föräldrars yrke eller utbildning på grundval av starka samband med elevers studieresultat. Uppsatsen tillämpar en rad metoder på data från en internationell kunskapsutvärdering och finner att sambandens styrka inte vilar på högre tillförlitlighet som tidigare förmodats, utan på endogenitetsproblem av två slag. Lågpresterande elever ackumulerar färre böcker och är dessutom benägna att underskatta deras antal. Studie III använder enkät- och registerdata för att belysa utlandsfödda föräldrars utbildning och dess samband med prestationer bland svenska skolbarn. Två aspekter av utbildningsbakgrund särskiljs: föräldrars utbildningsår samt deras relativa placering i ursprungslandets fördelning. Absolut utbildning visar sig predicera elevers testresultat och betyg, medan relativ utbildning är en bättre prediktor för barns aspirationer. Resultatet är av betydelse för studier av etniska skillnader där statistisk kontroll görs för observerbara föräldraegenskaper. Studie IV tillämpar den positionella ansatsen från Studie III för att förstå utlandsföddas självupplevda status och inkomsttillfredsställelse i europeiska länder. Migranter som är mer högutbildade med ursprungslandets mått mätt än värdlandets tenderar att ha en mer negativ bild av sin nuvarande situation än andra i objektivt liknande omständigheter. Detta kan förstås i termer av sociala referensramar och framhålls som relevant i tolkningen av långsiktiga sociala och ekonomiska integrationsmönster, inklusive de utbildningsval som efterföljande generationer gör. / <p>At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 2: Manuscript. Paper 3: Manuscript. Paper 4: Manuscript.</p>

This thesis consists of four self-contained essays in economics, all concerned with different aspects of subjective well-being. The abstracts of the four studies are as follows. Beyond Income: The Importance for Life Satisfaction of Having Access to a Cash Margin. We study how life satisfaction among adult Swedes is influenced by having access to a cash margin, i.e. a moderate amount of money that could be acquired on short notice either through own savings, by loan from family or friends, or by other means. We find that cash margin is a strong and robust predictor of life satisfaction, also when controlling for individual fixed effects and socio-economic conditions, including income. Decomposing Variation in Daily Feelings: The Role of Time Use and Individual Characteristics. I explore the potential of using time-use data for understanding variation in affective well-being. Using the Princeton Affect and Time Survey, I decompose variation in daily affect into explained and unexplained within- and between person variation. Time use is found to mostly account for within-variation. Hence, its explanatory power is largely additive to that of individual characteristics. The explanatory power of time use is small, however. Activities only account for 1–7% of the total variation and this is not increased much by adding contextual variables. The Association Between Life Satisfaction and Affective Well-Being. We estimate the correlation between life satisfaction and affect — two conceptually distinct dimensions of subjective well-being. We propose a simple model that distinguishes between a stable and a transitory component of affect, and which also accounts for measurement error in self-reports of both variables, including current-mood bias effects on life satisfaction judgments. The model is estimated using momentarily measured well-being data, from an experience sampling survey that we conducted on a population sample of Swedes aged 18–50 (n=252). Our main estimates of the correlation between life satisfaction and long-run affective well-being range between 0.78 and 0.91, indicating a stronger convergence between these variables than many previous studies that do not account for measurement issues. Do OLS and Ordinal Happiness Regressions Yield Different Results? A Quantitative Assessment. Self-reported subjective well-being scores are often viewed as ordinal variables, but the conventional wisdom has it that OLS and ordered regression models (e.g. ordered probit) produce similar results when applied to such data. This claim has rarely been assessed formally, however, in particular with respect to quantifying the differences. I shed light on this issue by comparing the results from OLS and different ordered regression models, in terms of both statistical and economic significance, and across data sets with different response scales for measuring life satisfaction. The results are mixed. The differences between OLS, probit and logit estimates are typically small when the response scale has few categories, but larger, though not huge, when an 11-point scale is used. Moreover, when the error term is assumed to follow a skewed distribution, larger discrepancies are found throughout. I find a similar pattern in simulations, in which I assess how different methods perform with respect to the true parameters of interest, rather than to each other.

This paper analyses the sources of income measurement error in surveys with a unique dataset.We use the Austrian 2008-2011 waves of EU-SILC which provide individual information on wages,pensions and unemployment benefits from survey interviews and officially linked administrativerecords. Thus, we do not have to fall back on complex two-sample matching procedures likerelated studies. We empirically investigate four sources of measurement error, namely (i) socialdesirability, (ii) socio-demographic characteristics of the respondent, (iii) the survey design, and(iv) the presence of learning effects. We find strong evidence for a social desirability bias inincome reporting, while the presence of learning effects is mixed and depends on the income typeunder consideration. An Owen value decomposition reveals that social desirability is a majorexplanation of misreporting in wages and pensions, whereas socio-demographic characteristicsare most relevant for mismatches in unemployment benefits. / Series: INEQ Working Paper Series

Introdução - A maior limitação para avaliar a dieta habitual é dada pelo erro de medida. Para minimizar os seus efeitos, tem-se proposto metodologias de calibração para correção dos dados e medidas associativas, consistindo na determinação de uma relação entre duas escalas de medida, utilizando-se regressão linear. Objetivo - Calibrar os dados obtidos por Questionário de Freqüência Alimentar para Adolescentes (QFAA), a partir do fator de calibração obtido por regressão linear. Metodologia - A amostra foi constituída por 74 adolescentes de ambos os sexos, alunos de uma escola pública de Piracicaba, com idade entre 10 e 14 anos. Foram excluídos indivíduos com idade superior ou igual a 14 anos ou com dados de consumo de energia não plausíveis. Obtiveram-se informações sobre dados socioeconômicos, antropométricos, demográficos e de maturação sexual. O consumo alimentar foi levantado por meio de Questionário de Freqüência Alimentar para Adolescentes e dois Recordatórios de 24 horas. Os dados de consumo de ambos os instrumentos foram ajustados pela energia, sendo que apenas os dados do recordatório foram ajustados pela variabilidade intrapessoal. Realizaram-se análises descritivas e de tendência central, one way ANOVA, coeficientes de correlação de Pearson e regressão linear. A média dos dois recordatórios foi utilizada como referência para a calibração dos dados. Resultados - De 74 indivíduos, 71,6% eram do sexo feminino. As médias das variáveis dietéticas foram muito semelhantes para o questionário calibrado e média dos recordatórios, com redução dos valores de desvio-padrão. Os coeficientes de calibração da regressão linear variaram de -0,05 (ferro) a 0,28 (vitamina C). Conclusão – Pelos resultados encontrados, a metodologia utilizada para a calibração dos dados dietéticos foi capaz de reduzir o erro de mensuração e, mesmo não o eliminando por completo, é uma abordagem que pode ser utilizada para obter estimativas menos enviesadas. / Background - A major limitation in usual diet assessment is the measurement error. Calibration approaches have been proposed to minimize its effects and to correct risk estimates. Calibration could be defined as a method which determines a relation between rank orders of two instruments by linear regression. Objective – to apply a calibration strategy in nutrient intake datas obtained by Adolescents Food Frequency Questionnaire (AFFQ), by using a calibration factor obtained by linear regression. Methodology – 74 boys and girls (10 to 14 years old) enrolled at a public school of Piracicaba were assessed. Values of energy intake higher than 6000Kcal and adolescents older than 14 years were excluded. Demographic and anthropometric data, sexual maturation and dietary intake (assessed by food frequency questionnaire and 24-hour recall) were examined. Dietary data intakes were adjusted by energy and, only 24-hour recall data were adjusted by within-person variance. Descriptive statistics, one way ANOVA, Pearson correlation coefficients and linear regression were performed. Results - 71,6% were girls. The calibrated values were similar to the reference data, with a reduction of standard deviation values. Linear regression coefficients (&#955;) ranged from -0,05 (iron) to 0,28 (vitamin C). Conclusion – The methodology used to calibrate dietary data was capable to reduce measurement error. Although it was not able to eliminate error completely, it is an approach that can be used to obtain less unbiased estimates.

Bakgrund: I hälso-och sjukvården är blodtrycksmätning en viktig och grundläggande metod vid korrekt diagnostik och hantering av högt blodtryck. Forskning har under flera år påvisat att olika komponenter påverkar noggrannheten av blodtrycksmätningen. Eftersom auskultatorisk och oscillometrisk blodtrycksmätning utförs på två olika sätt finns en risk att blodtrycksvärdet kan variera mellan metoderna. Syfte: Syftet med studien var att undersöka om det finns någon skillnad mellan auskultatorisk och oscillometrisk blodtrycksmätning utfört i både vila och efter ansträngning. Material och metod: Studien bestod av 20 slumpmässigt utvalda studenter från Hälsohögskolan i Jönköping. Blodtrycksmätning utfördes med hjälp av auskultatorisk blodtrycksmanschett med handmanometer och stetoskop samt oscillometrisk modalitet (OMRON M7). Resultat: Statistisk signifikant skillnad observerades mellan auskultatorisk och oscillometrisk modalitet, både i vila och efter ansträngning. Skillnaden är som störst efter ansträngning för auskultatorisk och oscillometrisk mätmetod, i både systoliskt och diastoliskt blodtrycksvärde. Diskussion: I vården har användning av oscillometrisk blodtrycksmodalitet ökat och därmed finns en risk för minskad reliabilitet och validitet av blodtrycksvärdet. Slutsatser: Statistisk signifikant skillnad föreligger mellan modaliteterna, både i vila och efter ansträngning. / Background: Blood pressure measurement is an important and fundamental method for correct diagnosis and management of high blood pressure, in healthcare. For several years, research has shown that different components affect the accuracy of blood pressure measurement. There is a risk that the blood pressure value may vary between auscultatory and oscillometric measurements because they are performed in two different ways. Purpose: The purpose was to investigate whether there is any difference between auscultatory and oscillometric blood pressure values performed in both rest and after stress. Material and method: The study consists of 20 randomly selected students from the School of Health and Welfare of Jönköping. The measurement was performed using auscultatory blood pressure cuff, sphygmomanometer with stethoscope and oscillometric modality (OMRON M7). Result: Statistically significant difference was observed between auscultatory and oscillometric values, both in rest and stress. The difference is greater after stress for both methods, in systolic and diastolic values. Discussion: In healthcare, use of oscillometric modality has increased thus there is a risk of reduced reliability and validity of the blood pressure value. Conclusion: Statistically significant difference was observed between auscultatory and oscillometric values, both in rest and after stress.

In spite of major research initiatives by DARPA and other research organizations, precise indoor geolocation still remains as a challenge facing the research community. The core of this challenge is to understand the cause of large ranging errors in estimating the time of arrival (TOA) of the direct path between the transmitter and the receiver. Results of wideband measurement in variety of indoor areas reveal that large ranging errors are caused by severe multipath conditions and frequent occurrence of undetected direct path (UDP) situations. Empirical models for the behavior of the ranging error, which we refer to as the distance measurement error (DME), its relation to the distance between the transmitter and the receiver and the bandwidth of the system is needed for development of localization algorithms for precise indoor geolocation. The main objective of this dissertation is to design a direct empirical model for the behavior of the DME. In order to achieve this objective we provide a framework for modeling of DME, which relates the error to the distance between the transmitter and the receiver and bandwidth of the system. Using this framework we first designed a set of preliminary models for the behavior of the DME based on the CWINS proprietary measurement calibrated ray-tracing simulation tool. Then, we collected a database of 2934 UWB channel impulse response measurements at 3-8GHz in four different buildings to incorporate a variety of building materials and architectures. This database was used for the design of more in depth and realistic models for the behavior of the DME. The DME is divided into two components, Multipath-DME (MDME) and UDP-DME (UDME). Based on the empirical data, models for the behavior of each of these components are developed. These models reflect the sensitivity to bandwidth and show that by increasing the bandwidth MDME decreases. However in UDME the behavior is complicated. At first it reduces as we increase the bandwidth but after a certain bandwidth it starts to increase. In addition to these models through an analysis on direct path power versus the total power the average probability of having a UDP was calculated.

Objective. To use cognitive interviewing techniques to determine faculty and student interpretation of a subset of items from the AACP faculty and graduating student surveys. Methods. Students and faculty were interviewed individually in a private room. The interviewer asked each respondent for his/her interpretation of 15 randomly selected items from the graduating student survey or 20 items from the faculty survey. Results. While many items were interpreted consistently by respondents, the researchers identified several items that were either difficult to interpret or produced differing interpretations. Conclusion. Several interpretational inconsistencies and ambiguities were discovered that could compromise the usefulness of certain survey items.

Doctor of Philosophy / Over the past decade, population-based cancer registry data have been used increasingly worldwide to evaluate and improve the quality of cancer care. The utility of the conclusions from such studies relies heavily on the data quality and the methods used to analyse the data. Interpretation of comparative survival from such data, examining either temporal trends or geographical differences, is generally not easy. The observed differences could be due to methodological and statistical approaches or to real effects. For example, geographical differences in cancer survival could be due to a number of real factors, including access to primary health care, the availability of diagnostic and treatment facilities and the treatment actually given, or to artefact, such as lead-time bias, stage migration, sampling error or measurement error. Likewise, a temporal increase in survival could be the result of earlier diagnosis and improved treatment of cancer; it could also be due to artefact after the introduction of screening programs (adding lead time), changes in the definition of cancer, stage migration or several of these factors, producing both real and artefactual trends. In this thesis, I report methods that I modified and applied, some technical issues in the use of such data, and an analysis of data from the State of New South Wales (NSW), Australia, illustrating their use in evaluating and potentially improving the quality of cancer care, showing how data quality might affect the conclusions of such analyses. This thesis describes studies of comparative survival based on population-based cancer registry data, with three published papers and one accepted manuscript (subject to minor revision). In the first paper, I describe a modified method for estimating spatial variation in cancer survival using empirical Bayes methods (which was published in Cancer Causes and Control 2004). I demonstrate in this paper that the empirical Bayes method is preferable to standard approaches and show how it can be used to identify cancer types where a focus on reducing area differentials in survival might lead to important gains in survival. In the second paper (published in the European Journal of Cancer 2005), I apply this method to a more complete analysis of spatial variation in survival from colorectal cancer in NSW and show that estimates of spatial variation in colorectal cancer can help to identify subgroups of patients for whom better application of treatment guidelines could improve outcome. I also show how estimates of the numbers of lives that could be extended might assist in setting priorities for treatment improvement. In the third paper, I examine time trends in survival from 28 cancers in NSW between 1980 and 1996 (published in the International Journal of Cancer 2006) and conclude that for many cancers, falls in excess deaths in NSW from 1980 to 1996 are unlikely to be attributable to earlier diagnosis or stage migration; thus, advances in cancer treatment have probably contributed to them. In the accepted manuscript, I described an extension of the work reported in the second paper, investigating the accuracy of staging information recorded in the registry database and assessing the impact of error in its measurement on estimates of spatial variation in survival from colorectal cancer. The results indicate that misclassified registry stage can have an important impact on estimates of spatial variation in stage-specific survival from colorectal cancer. Thus, if cancer registry data are to be used effectively in evaluating and improving cancer care, the quality of stage data might have to be improved. Taken together, the four papers show that creative, informed use of population-based cancer registry data, with appropriate statistical methods and acknowledgement of the limitations of the data, can be a valuable tool for evaluating and possibly improving cancer care. Use of these findings to stimulate evaluation of the quality of cancer care should enhance the value of the investment in cancer registries. They should also stimulate improvement in the quality of cancer registry data, particularly that on stage at diagnosis. The methods developed in this thesis may also be used to improve estimation of geographical variation in other count-based health measures when the available data are sparse.

隨著經濟不斷的發展，企業間的競爭也愈趨激烈，因此在以利潤最大、付出成本最小的前提下，一些可能造成成本增加的因素就不能不重視。在量測產品的特性所使用的量測機器，可能因為量測設備的不精確造成誤差，進而影響測量產品品質特性的實際值。是以量測儀器測量產品特性時的誤差對於管制圖的設計參數的影響及使用管制圖監控製程的能力是我們所關切的課題。 本文探討量測誤差對 — 管制圖的效應。運用George Tagaras非對稱管制圖的概念，及同時考慮Taguchi的損失函數和測量誤差下，以更新理論方法建立 — 管制圖，並推導出目標函數，再透過最佳化的技巧以決定 — 管制圖的最佳經濟設計參數值。另外討論管制圖在統計層面的表現，並與經濟設計的結果作比較。 在資料分析方面，本研究考慮32組製程和成本參數組合，透過最佳化技巧找出 — 經濟及經濟統計管制圖之最小單位時間平均成本及最佳設計參數組合。再利用敏感度分析，觀察量測誤差對設計參數的影響，另外得知重要的製程和成本參數為何。這些可作為製程工程師決策參考之用。