In intervention research, single-case experimental designs are an important way to gain insights into the causes of individual changes that yield high internal validity. They are commonly applied to examine the effectiveness of classroom-based interventions to reduce problem behavior in schools. At the same time, there is no consensus on good design characteristics of single-case experimental designs when dealing with behavioral problems in schools. Moreover, specific challenges arise concerning appropriate approaches to analyzing behavioral data. Our study addresses the interplay between the test power of piecewise regression analysis and important design specifications of single-case research designs. Here, we focus on the influence of the following specifications of single-case research designs: number of measurement times, the initial frequency of the behavior, intervention effect, and data trend. We conducted a Monte-Carlo study. First, simulated datasets were created with specific design conditions based on reviews of published single-case intervention studies. Following, data were analyzed using piecewise Poisson-regression models, and the influence of specific design specifications on the test power was investigated. Our results indicate that piecewise regressions have a high potential of adequately identifying the effects of interventions for single-case studies. At the same time, test power is strongly related to the specific design specifications of the single-case study: Few measurement times, especially in phase A, and low initial frequencies of the behavior make it impossible to detect even large intervention effects. Research designs with a high number of measurement times show robust power. The insights gained are highly relevant for researchers in the field, as decisions during the early stage of conceptualizing and planning single-case experimental design studies may impact the chance to identify an existing intervention effect during the research process correctly.

Social comparison processes and the social position within a school class already play a major role in performance evaluation as early as in elementary school. The influence of contrast and assimilation effects on self-evaluation of performance as well as task interest has been widely researched in observational studies under the labels big-fish-little-pond and basking-in-reflected-glory effect. This study examined the influence of similar contrast and assimilation effects in an experimental paradigm. Fifth and sixth grade students (n = 230) completed a computer-based learning task during which they received social comparative feedback based on 2 × 2 experimentally manipulated feedback conditions: social position (high vs. low) and peer performance (high vs. low). Results show a more positive development of task interest and self-evaluation of performance in both the high social position and the high peer performance condition. When applied to the school setting, results of this study suggest that students who already perform well in comparison to their peer group are also the ones who profit most from social comparative feedback, given that they are the ones who usually receive the corresponding positive performance feedback.

Modellen der Sprachaneignung zufolge sind für die die Entwicklung sprachlicher Fähigkeiten auch die sprachlichen Fähigkeiten von wichtigen Interaktionspartnern (z. B. Peers) bedeutsam. Da objektive Kompetenzmaße von Interaktionspartnern selten verfügbar sind, könnten alternativ Fremdeinschätzungen der sprachlichen Fähigkeiten erhoben werden. Im Beitrag wurden daher Schülerurteile über sprachliche Fähigkeiten von Mitschüler(inne)n im Deutschen und den Herkunftssprachen Türkisch und Russisch als potentielle Indikatoren tatsächlicher Sprachfähigkeiten untersucht. Mit Hilfe von Mehrebenenmodellen wurde analysiert, welchen Einflussfaktoren die Fremdeinschätzungen unterlagen, wie akkurat diese ausfielen und unter welchen Bedingungen akkuratere Einschätzungen gelangen. In allen Sprachen ergaben sich moderate Zusammenhänge zwischen den Fremdeinschätzungen und objektiven Leistungsmaßen, wobei die Urteilsakkuratheit insbesondere von Merkmalen auf der Beziehungsebene zur eigeschätzten Person (gemeinsamer Unterricht, geteilter Sprachhintergrund, Beziehungsqualität) moderiert wurde. Im Deutschen zeigten sich negative leistungsbezogene Vorurteile gegenüber Jugendlichen mit türkischer und russischer Herkunftssprache. Die Ergebnisse werden in Bezug auf Möglichkeiten und Grenzen von Fremdeinschätzungen sprachlicher Fähigkeiten sowie auf Konsequenzen leistungsbezogener Vorurteile diskutiert.

Concrete-operational thinking depicts an important aspect of cognitive development. A promising approach in promoting these skills is the instruction of strategies. The construction of such instructional programs requires insights into the mental operations involved in problem-solving. In the present paper, we address the question to which extent variations of the effect of isolated and combined mental operations (strategies) on correct solution of concrete-operational concepts can be observed. Therefore, a cross-sectional design was applied. The use of mental operations was measured by thinking-aloud reports from 80 first- and second-graders (N = 80) while solving tasks depicting concrete-operational thinking. Concrete-operational thinking was assessed using the subscales conservation of numbers, classification and sequences of the TEKO. The verbal reports were transcribed and coded with regard to the mental operations applied per task. Data analyses focused on tasks level, resulting in the analyses of N = 240 tasks per subscale. Differences regarding the contribution of isolated and combined mental operations (strategies) to correct solution were observed. Thereby, the results indicate the necessity of selection and integration of appropriate mental operations as strategies. The results offer insights in involved mental operations while solving concrete-operational tasks and depict a contribution to the construction of instructional programs.