The process of research is fraught with rote terminology that, when used blindly, can bend our methodological actions away from our theoretical intentions. This investigation is aimed at developing two methods for bringing meaning and interpretability to research when we work with confounds. I argue, with the first method, that granting confounds substantive influence in a network of related variables (rather than viewing confounds as nuisance variables) enhances the conceptual dimension with which phenomena can be explained. I evaluated models differing in how confounds were specified using data from the Survey of Health, Ageing and Retirement in Europe (SHARE). Generally, minor alterations to model specifications, such as direction of causal pathways, did not change model parameter estimates; however, the conceptual meaning of how the confounds interacted with other variables in the model changed drastically. Another frequent misconceptualization of confounds, detailed by the second method, occurs when confounds are used as proxy variables to control for variance that is not directly measureable, and no explicit attempt is made to ensure that the proxy variable adequately represents the underlying, intended construct. For this second demonstration, I used SHARE data to estimate models varying in the degree to which proxy variables represent intended variables. Results showed that parameter estimates can differ substantially across different levels of proxy variable representation. When imperfect proxy variables are used, an insufficient amount of variance is removed from the observed spurious relationship between design variables. The findings from this methodological demonstration underscore the importance of precisely imbuing confounds with conceptual meaning and selecting proxy variables that accurately represent the underlying construct for which control is intended.

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 contributes to the field of causal inference, where the main interest is to estimate the effect of a treatment on some outcome. At its core, causal inference is an exercise in controlling for imbalance (differences) in covariate distributions between the treated and the controls, as such imbalances otherwise can bias estimates of causal effects. Imbalance on observed covariates can be handled through matching, where treated and controls with similar covariate distributions are extracted from a data set and then used to estimate the effect of a treatment. The first paper of this thesis describes and investigates a matching design, where a data-driven algorithm is used to discretise a covariate before matching. The paper also gives sufficient conditions for if, and how, a covariate can be discretised without introducing bias. Balance is needed for unobserved covariates too, but is more difficult to achieve and verify. Unobserved covariates are sometimes replaced with correlated counterparts, usually referred to as proxy variables. However, just replacing an unobserved covariate with a correlated one does not guarantee an elimination of, or even reduction of, bias. In the second paper we formalise proxy variables in a causal inference framework and give sufficient conditions for when they lead to nonparametric identification of causal effects. The third and fourth papers both concern estimating the effect an enhanced cooperation between the Swedish Social Insurance Agency and the Public Employment Service has on reducing sick leave. The third paper is a study protocol, where the matching design used to estimate this effect is described. The matching was then also carried out in the study protocol, before the outcome for the treated was available, ensuring that the matching design was not influenced by any estimated causal effects. The third paper also presents a potential proxy variable for unobserved covariates, that is used as part of the matching. The fourth paper then carries out the analysis described in the third paper, and uses an instrumental variable approach to test for unobserved confounding not captured by the supposed proxy variable.