| 研究概要 |
The current study examined the empirical nature of theorized conceptions of vocabulary depth under factor analytic methods. Four constructs of L2 vocabulary knowledge were examined: Receptive vocabulary knowledge, productive vocabulary size, receptive word associations and productive word associations as scored using a norming group of native-speaker responses.
Responses of 683 first and second year Japanese university students to the four tests were analyzed under exploratory and confirmatory factor analyses using Mplus 7.1 with the robust weighted least squares (WLSMV) estimator, which allows for analysis of categorical data such as dichotomous test responses.
Although an EFA indicated both 3 and 4 factor solutions had good fit to the data (RMSEA=0.19, 0.14), a 4-factor CFA (RMSEA=0.02; CFI=0.93) showed very high factor correlations between the constructs of receptive and productive vocabulary knowledge (0.849), indicating strong multicollinearity. In accordance to the findings of Laufer, Elder Hill & Congdon (2004), in which these two constructs were measured concurrently as unidimensional, the two constructs were therefore merged into a single construct of “definitional meaning”.
A final model in which responses to definitional meaning and receptive word association test items are governed by both a general factor of vocabulary knowledge and unique factors (i.e., a bifactor model) and productive word associations are modelled as a distinct, uncorrelated factor had both the best fit to the data (RMSEA = 0.014; CFI = 0.97) and a clear theoretical interpretation.
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