355 research outputs found
A Monte-Carlo study to evaluate value-addedmodels for institutions’ rankings
No full textThe aim of this paper is to assess the quality of the ranking of institutions
obtained with different types of widely used random and fixed effects value-added
models. Through a Monte Carlo simulation study we assess the robustness of the
ranking obtained in the presence of different model misspecifications and data structures.
Coherently with the well-established literature, we find that it is quite hard to
obtain a reliable ranking of the whole effectiveness distribution, while it is possible
to identify institutions with extreme performances under various experimental
conditions. Multilevel models where the between and within cluster components of
first-level covariates are distinguished perform significantly better than both multilevel
models where the two effects are set to be equal and fixed effect models. We
also find that the estimated rankings are of poor quality when the effectiveness distribution
does not follow a symmetric and unimodal distribution. For these situations
we plan to explore simple data transformations, as the Box-Cox, and non-parametric
methods for the estimation of random effects that can help to obtain a better ranking
Assessing the quality of institutions’ rankings obtained through multilevel linear regression models
No full textThe aim of this paper is to assess the quality of the ranking of institutions obtained with
multilevel techniques in presence of different model misspecifications and data structures.
Through a Monte Carlo simulation study, we find that it is quite hard to obtain a reliable
ranking of the whole effectiveness distribution while, under various experimental conditions,
it is possible to identify institutions with extreme performances. Ranking quality increases
with increasing intra class correlation coefficient and/or overall sample size. Furthermore,
multilevel models where the between and within cluster components of first-level covariates
are distinguished perform significantly better than both multilevel models where the two
effects are set to be equal and the fixed effect models
I recettori per gli androgeni e gli estrogeni nel testicolo della lucertola, Podarcis sicula: un’analisi molecolare
No full text
Tempi di conseguimento del titolo nell’Ateneo fiorentino durante il periodo 1980-2000
No full textNel corso degli ultimi anni il sistema universitario italiano è stato investito da un
profondo processo di cambiamento normativo culminato, nell’anno accademico
2001/02, con l’avvio della riforma dei cicli e degli ordinamenti didattici.
In questo ambito così dinamico e in evoluzione si è reso ancor più necessario
rispetto al passato un processo di controllo e valutazione delle performance
universitarie, sia per quanto riguarda l’efficacia interna del sistema sia per quanto riguarda
la sua efficacia esterna. In questo contesto, il presente lavoro analizza i tempi di conseguimento del titolo nell’Ateneo fiorentino durante il periodo 1980-2000, con tecniche di statistica descrittiva e modelli di regressione multilivello
Ranking of Universities Effectiveness Using Multilevel Linear Regression: Robustness to Model Misspecifications
No full textIn the educational field one aim of the research is to evaluate the school or university
effectiveness. In particular, the researcher is usually interested in obtaining a rank of the
institutions and multilevel modeling is a widely applied tool to achieve this goal.
This paper focuses on the evaluation of the robustness of the ranking obtained with
multilevel models in case of different misspecifications of the model. The analyses are
carried out through Monte Carlo simulations
Robust ANalysis Of VAriance: an approach based on the Forward Search
No full textA simple robust method for the detection of atypical observations and the analysis of their effect in the ANOVA framework is presented. It is proposed to use a forward search procedure that orders the observations by their closeness to the hypothesized model. The procedure can be applied following two different strategies: one that adds units maintaining the relative group dimension and the other that adds only one new unit at each step of the search. The assessment of the goodness of the method is carried out through a simulation study. The method is then applied to real data. Results are presented through easy to interpret plots which are powerful in revealing the structure of the data. © 2006 Elsevier B.V. All rights reserved
REGULATION OF ANDROGEN RECEPTOR MRNA EXPRESSION IN PRIMARY CULTURE OF HARDERIAN GLAND CELLS: CROSS TALK BETWEEN STEROID HORMONES
No full textAutoinduction of androgen receptor mRNA is associated with induction of MHG19 gene in primary cultures of male hamster Harderian gland cells
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