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Part 2: The Measurement of Implicit and Explicit Knowledge
average, they had been learning English for 10.0 years, mostly in a foreign language context they had spent an average of only 1.9 years living in an English-speaking country. Most (70.5%) of the L2 learners came from China. Test content The tests were designed to provide measures of learners’ knowledge of 17 English grammatical structures. The choice of the grammatical content was driven by a number of considerations. First and foremost, an attempt was made to select target language structures that were known to be universally problematic to learners (i.e. to result in errors). To this end, the SLA literature on error analysis was consulted (e.g. Burt & Kiparsky, 1972). Second, the structures were selected to represent both early and late acquired grammatical features according to what is known about the developmental properties of L2 acquisition (e.g. Pienemann, 1989). Third, the structures were selected to represent a broad range of proficiency levels according to when they were introduced in English as a Second Language (ESL) courses covering beginner, lower-intermediate, upper-intermediate and advanced levels. Fourth, the structures were chosen to include both morphological and syntactic features. Table 2.2 lists the structures and summarizes their properties in terms of the various selection criteria. The test battery A total of five tests were developed. The main properties of these tests were as follows: (1) Elicited Oral Imitation Test This consisted of a set of belief statements (involving both grammatical and ungrammatical sentences containing the target structures). In the original version of this test, there were 68 statements. However, in order to shorten the time it took to administer this test, this number was subsequently reduced to 34 statements (one grammatical and one ungrammatical sentence per structure) by selecting those sentences that correlated most strongly with total test scores in an initial sample of 50 L2 learners and 10 native speakers and, therefore, were considered the best measures of the underlying construct. The sentences were presented orally to test-takers, who were required to say first whether they agreed with, disagreed with or were not sure about the content of each statement. This was intended to focus their attention on meaning. Second, the test-takers were asked to repeat the sentences orally in correct English. The test-takers’ responses were audiorecorded. The responses were then analyzed by identifying obligatory occasions