No abstract

FACETS many-facet Rasch analysis software (Linacre, 1998a) was utilized to look at two consecutive administrations of a large-scale (more than 1000 examinees) second language oral assessment in the form of a peer group discussion task with Japanese English-major university students. Facets modeled in the analysis were examinee, prompt, rater, and ve rating category 'items.' Unidimensionality was shown to be strong in both datasets, and approaches to interpreting t values for the facets modeled in the analysis were discussed. Examinee ability was the most substantial facet, followed by rater severity, and item. The prompt facet was negligible in magnitude. Rater differences in terms of severity were generally large, but this characteristic was not stable over time for individuals; returning raters tended to move toward greater severity and consistency, while new raters showed much more inconsistency. Analysis of the scales showed general validity in gradations of scale steps, though raters had some dif culty discerning between categories at the ends of the scales for pronunciation and communicative skills.

T his arlicJc s t•mmarizcs findings from inv~s tigaci on s into the development and usc of n pr<)LOtype English language task-based performance tcs~. D::H~ inc-luded pcrfonmmces by 90 examinees on 13 complex and sk ills ·inlcg ra~ivctasks. a priori estimaliOJlS of examinee proficiency differe nc-es, tt priori esL imaiJons of task dif1iculcy based on cognitive processing demands. pe-rformance ratings accord ing L o ta.sk-SJ)C.Citlc as well as holistic scales a nd criteria, and cxamincesdf-ratings. Findings indicated that the task-based test could infonn intended illferMces about examinees· abi lities to accomplish spcx:ific tasks as wcU as inference..'>aboul examinees' likely abilities with a dom;ain of tasks. A llhough a relationship between task difficulty esLimaL es and examinee pcrformance.s was observed, these estimates were not found ~o provide a lru.stworlhybasis for infe1 ·ringexaminees' likely abiliLies with other tasks. These findings, as weU as srudy limitations, are further discussed in light o f the inLended uses for perfom1ance assessment within kmg\mge education, ~m d rccomrneJldatior\S are made for needed. rcsc.·uch into the interaction bel ween task features. cogniLive processing and l~mguage perronnarlce.

cupy a separate family of its own. The karyotype of Callimico is intermediate between the marmoset karyotype and that of the cebid genus Callicebus. It can only be said that in this case the chromosomal evidence is in agreement with the idea, expressed by Hill (36), that the Callithricidae are a specialized, rather than a primitive group, and that Callimico is more primitive (and unspecialized) and is hence probably closer to the ancestral cebid stem.References and Notes 1.

No abstract