@article{SchmidtBrunnerPreckel2018,
  author    = {Schmidt, Isabelle and Brunner, Martin and Preckel, Franzis},
  title     = {Effects of achievement differences for internal/external frame of reference model investigations},
  series = {British journal of educational psychology},
  volume    = {88},
  journal   = {British journal of educational psychology},
  number    = {4},
  publisher = {Wiley},
  address   = {Hoboken},
  issn      = {0007-0998},
  doi       = {10.1111/bjep.12198},
  pages     = {513 -- 528},
  year      = {2018},
  abstract  = {Background Achievement in math and achievement in verbal school subjects are more strongly correlated than the respective academic self-concepts. The internal/external frame of reference model (I/E model; Marsh, 1986, Am. Educ. Res. J., 23, 129) explains this finding by social and dimensional comparison processes. We investigated a key assumption of the model that dimensional comparisons mainly depend on the difference in achievement between subjects. We compared correlations between subject-specific self-concepts of groups of elementary and secondary school students with or without achievement differences in the respective subjects. Aims The main goals were (1) to show that effects of dimensional comparisons depend to a large degree on the existence of achievement differences between subjects, (2) to demonstrate the generalizability of findings over different grade levels and self-concept scales, and (3) to test a rarely used correlation comparison approach (CCA) for the investigation of I/E model assumptions. Samples We analysed eight German elementary and secondary school student samples (grades 3-8) from three independent studies (Ns 326-878). Method Correlations between math and German self-concepts of students with identical grades in the respective subjects were compared with the correlation of self-concepts of students having different grades using Fisher's Z test for independent samples. Results In all samples, correlations between math self-concept and German self-concept were higher for students having identical grades than for students having different grades. Differences in median correlations had small effect sizes for elementary school students and moderate effect sizes for secondary school students. Conclusions Findings generalized over grades and indicated a developmental aspect in self-concept formation. The CCA complements investigations within I/E-research.},
  language  = {en}
}
@article{KellerPreckelBrunner2021,
  author    = {Keller, Lena and Preckel, Franzis and Brunner, Martin},
  title     = {Nonlinear relations between achievement and academic self-concepts in elementary and secondary school},
  series = {Journal of educational psychology / American Psychological Association},
  volume    = {113},
  journal   = {Journal of educational psychology / American Psychological Association},
  number    = {3},
  publisher = {American Psychological Association},
  address   = {Washington},
  issn      = {0022-0663},
  doi       = {10.1037/edu0000533},
  pages     = {585 -- 604},
  year      = {2021},
  abstract  = {It is well-documented that academic achievement is associated with students' self-perceptions of their academic abilities, that is, their academic self-concepts. However, low-achieving students may apply self-protective strategies to maintain a favorable academic self-concept when evaluating their academic abilities. Consequently, the relation between achievement and academic self-concept might not be linear across the entire achievement continuum. Capitalizing on representative data from three large-scale assessments (i.e., TIMSS, PIRLS, PISA; N = 470,804), we conducted an integrative data analysis to address nonlinear trends in the relations between achievement and the corresponding self-concepts in mathematics and the verbal domain across 13 countries and 2 age groups (i.e., elementary and secondary school students). Polynomial and interrupted regression analyses showed nonlinear relations in secondary school students, demonstrating that the relations between achievement and the corresponding self-concepts were weaker for lower achieving students than for higher achieving students. Nonlinear effects were also present in younger students, but the pattern of results was rather heterogeneous. We discuss implications for theory as well as for the assessment and interpretation of self-concept.},
  language  = {en}
}