The current study examined the influence of classroom age composition (the variability in ages of children in the classroom) on low-income preschool children's rates of change in multiple domains of school readiness. The sample consisted of 4,417 preschool children enrolled in 207 classrooms in a large, diverse Head Start program. Children were assessed throughout the year on four school readiness domains: emergent literacy, emergent numeracy, social and emotional skills, and approaches to learning. Multilevel modeling was employed to examine the main effect of classroom age composition as well as the interaction between classroom age composition and child's age as predictors of children's rates of change in these school readiness domains. Results showed that classroom age composition did not uniformly influence rates of change in school readiness for all children. Instead, a significant interaction between child's age and classroom age composition indicated that younger children developed skills in the domain of approaches to learning at an increased rate when placed in classrooms with a large age composition (i.e., in classrooms with a greater degree of age-mixing). This study extends literature focused on identifying classroom structures that promote positive development of school readiness skills, particularly for at-risk children.

The aim of the thesis is to describe and analyse the population redistribution in Sweden at different geographical levels from the beginning of the 19th century to the end of the 20th century. The analysis is approached in three different ways. First, the redistribution at different geographical levels is analysed (papers I and II). Second, the changing accessibility between people (interpersonal accessibility) is analysed from the beginning of the 19th century to the end of the 20th century (paper II). Third, the impacts of fertility, mortality, internal migration, international migration and geographical variations in age composition on population distribution are analysed for the last decades (papers I, III and IV). Measurements of concentration have been used in order to analyse the changing population distribution. For the analysis of changing interpersonal accessibility the average population within the daily reach has been calculated for different times. In order to analyse the impacts of fertility, mortality, migration and geographical variations in age composition the actual redistribution of the population is compared with the redistribution generated by a number of counterfactual scenarios. To analyse the impact of international migration the changing distribution of the population in different immigrant groups is compared to the distribution of the Swedish population. Some conclusions drawn from the thesis are: 1. There is no overall trend in the population redistribution towards either concentration or dispersion. The redistribution pattern depends on the time perspective and the geographical level chosen. The population has been both concentrated and dispersed since the beginning of the 19th century. This applies to all investigated geographical levels. In the five identified phases of the redistribution the most common pattern is that concentration and dispersion of the population exist simultaneously on different geographical levels. The total effect of the redistribution between 1810 and 1990 is that today the population is more dispersed at macro-regional level, while it is more concentrated at local and regional level. 2. Based on assumptions about the daily reach, an average person today has access to about 100 times more people locally compared with the beginning of the 19th century. The most important process for the increased accessibility has been the redistribution of the population. The process that has had the least impact is the assumed increase in daily reach. However the importance of the investigated processes changes over time. Since 1950 the increasing reach has been the most important process. However, the rate by which interpersonal accessibility increases has slowed down since 1950. 3. The main demographic factor behind the redistribution since 1970 is the geographical differences in age composition and its effects on the natural population change. It is demonstrated that this factor lies behind the trend towards increasing concentration in Sweden, while the impact of migration affects the fluctuations from this trend to a greater extent. 4. The study shows that immigration concentrates the population, while the internal migration during the 1970s and periodically during the 1980s dispersed the population. However during the 1990s the internal migration has had a concentrating effect on the spatial distribution of the population. / <p>Diss. (sammanfattning) Umeå : Umeå universitet, 2000, härtill 4 uppsatser</p> / digitalisering@umu