@article{GronostajVockPant2016,
  author    = {Gronostaj, Anna and Vock, Miriam and Pant, Hans Anand},
  title     = {Skip a grade, learn more? Estimating the effects of grade skipping on},
  series = {Learning and individual differences},
  volume    = {49},
  journal   = {Learning and individual differences},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {1041-6080},
  doi       = {10.1016/j.lindif.2016.05.022},
  pages     = {278 -- 286},
  year      = {2016},
  abstract  = {Acceleration, defined as progressing through educational programs faster or at a younger age than peers (Pressey, 1949), is an educational practice that is used to support gifted and high-ability students whose cognitive and affective needs might not be met in age-based classrooms. The empirical results of grade skipping, one specific form of acceleration, have been supportive with respect to academic outcomes but have primarily been derived from U.S. samples. Less is known about German grade skippers. We reanalyzed the test and survey data of more than 40,000 students from five studies originally conducted to assess their skills in native and foreign languages in the context of the national educational standards in Germany. We identified 471 grade skippers and used propensity score matching on potential confounding variables (e.g., intelligence, gender, parental background) to construct comparable control groups. Two different comparison groups were realized (same-grade and same age groups). The findings showed that grade skippers performed (at least) as well on standardized tests as their older classmates who were matched on all covariates (same-grade comparison) and outperformed their same-aged peers who were matched on all covariates in most of the language skills that were assessed. Practical and methodological implications are also discussed. (C) 2016 Elsevier Inc. All rights reserved.},
  language  = {en}
}
@article{KretschmannVockLuedtkeetal.2016,
  author    = {Kretschmann, Julia and Vock, Miriam and Luedtke, Oliver and Gronostaj, Anna},
  title     = {psychosocial development after early acceleration},
  series = {Contemporary educational psychology},
  volume    = {46},
  journal   = {Contemporary educational psychology},
  publisher = {Elsevier},
  address   = {San Diego},
  issn      = {0361-476X},
  doi       = {10.1016/j.cedpsych.2016.06.001},
  pages     = {195 -- 207},
  year      = {2016},
  abstract  = {Whereas studies that have analyzed factors that affect academic achievement have predominantly revealed positive effects of skipping a grade, controversial results have been found for students' social-emotional and motivational development. Therefore, the aim of this study was to examine the effects of skipping a whole grade on students' school satisfaction, peer relations, school anxiety, and academic self-concept. Moreover, we conducted moderation analyses to investigate whether skipping a grade affects boys and girls differently. Data were obtained from N = 4926 German students who were repeatedly surveyed once a year in Grades 4, 5, and 6. A total of N = 96 students from this sample had skipped a grade in elementary school. We applied full matching separately for male and female students in order to minimize selection bias. When analyzing motivational variables, we added class-mean achievement scores as covariates within the matching process. Equally for boys and girls, the results showed no significant effect of skipping on school satisfaction, yet we found a negative effect on peer relations that persisted across the 3 years of measurement. However, after skipping a grade girls were significantly disadvantaged compared to boys on some motivational dimensions.},
  language  = {en}
}
@misc{SandauChaabeneGranacher2021,
  author    = {Sandau, Ingo and Chaabene, Helmi and Granacher, Urs},
  title     = {Concurrent validity of barbell force measured from video-based barbell kinematics during the snatch in male elite weightlifters},
  series = {Postprints der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe},
  journal   = {Postprints der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe},
  number    = {716},
  issn      = {1866-8364},
  doi       = {10.25932/publishup-52167},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-521678},
  pages     = {13},
  year      = {2021},
  abstract  = {This study examined the concurrent validity of an inverse dynamic (force computed from barbell acceleration [reference method]) and a work-energy (force computed from work at the barbell [alternative method]) approach to measure the mean vertical barbell force during the snatch using kinematic data from video analysis. For this purpose, the acceleration phase of the snatch was analyzed in thirty male medal winners of the 2018 weightlifting World Championships (age: 25.2±3.1 years; body mass: 88.9±28.6 kg). Vertical barbell kinematics were measured using a custom-made 2D real-time video analysis software. Agreement between the two computational approaches was assessed using Bland-Altman analysis, Deming regression, and Pearson product-moment correlation. Further, principal component analysis in conjunction with multiple linear regression was used to assess whether individual differences related to the two approaches are due to the waveforms of the acceleration time-series data. Results indicated no mean difference (p > 0.05; d = -0.04) and an extremely large correlation (r = 0.99) between the two approaches. Despite the high agreement, the total error of individual differences was 8.2\% (163.0 N). The individual differences can be explained by a multiple linear regression model (R2adj = 0.86) on principal component scores from the principal component analysis of vertical barbell acceleration time-series waveforms. Findings from this study indicate that the individual errors of force measures can be associated with the inverse dynamic approach. This approach uses vertical barbell acceleration data from video analysis that is prone to error. Therefore, it is recommended to use the work-energy approach to compute mean vertical barbell force as this approach did not rely on vertical barbell acceleration.},
  language  = {en}
}
@article{SandauChaabeneGranacher2021,
  author    = {Sandau, Ingo and Chaabene, Helmi and Granacher, Urs},
  title     = {Concurrent validity of barbell force measured from video-based barbell kinematics during the snatch in male elite weightlifters},
  series = {PLOS ONE / Public Library of Science},
  volume    = {16},
  journal   = {PLOS ONE / Public Library of Science},
  number    = {7},
  publisher = {PLOS},
  address   = {San Francisco},
  issn      = {1932-6203},
  doi       = {10.1371/journal.pone.0254705},
  pages     = {11},
  year      = {2021},
  abstract  = {This study examined the concurrent validity of an inverse dynamic (force computed from barbell acceleration [reference method]) and a work-energy (force computed from work at the barbell [alternative method]) approach to measure the mean vertical barbell force during the snatch using kinematic data from video analysis. For this purpose, the acceleration phase of the snatch was analyzed in thirty male medal winners of the 2018 weightlifting World Championships (age: 25.2±3.1 years; body mass: 88.9±28.6 kg). Vertical barbell kinematics were measured using a custom-made 2D real-time video analysis software. Agreement between the two computational approaches was assessed using Bland-Altman analysis, Deming regression, and Pearson product-moment correlation. Further, principal component analysis in conjunction with multiple linear regression was used to assess whether individual differences related to the two approaches are due to the waveforms of the acceleration time-series data. Results indicated no mean difference (p > 0.05; d = -0.04) and an extremely large correlation (r = 0.99) between the two approaches. Despite the high agreement, the total error of individual differences was 8.2\% (163.0 N). The individual differences can be explained by a multiple linear regression model (R2adj = 0.86) on principal component scores from the principal component analysis of vertical barbell acceleration time-series waveforms. Findings from this study indicate that the individual errors of force measures can be associated with the inverse dynamic approach. This approach uses vertical barbell acceleration data from video analysis that is prone to error. Therefore, it is recommended to use the work-energy approach to compute mean vertical barbell force as this approach did not rely on vertical barbell acceleration.},
  language  = {en}
}