Perceptions on the Validity of the Test Based on the Interview
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F considered that the test contained content validity. They affirmed that the test material really represented the section they had to study. In other words, the
material they had to study was relevant with the test administered. Besides, the material they had to master was meaningful and useful to lead them doing the test.
Nonetheless, there was one interviewee, namely student E who argued that he was confused with the test material. He confessed that he was never prepared
to master the section he had to study. Thus, he even did not know whether the material signified the section he had to master.
In relation to the face validity of the test namely the instructions of the tests, the researcher found that all interviewees admitted the clarity of the
instructions of the tests. As described in the questionnaire results, there were 88 students confessing that the instructions of the tests were clear. Thus, through
their responses in the interview, the interviewees had verified the data acquired from the questionnaire.
Moreover, there were four interviewees who admitted that the tests really measured their ability in mastering vocabulary. Student A, student B, student D
and student F had similar responses. Generally, they confessed that the tests were able to measure to what extent they had mastered vocabulary items. The tests
indeed measured just the ability to master vocabulary items, not the other ability. It meant that their responses reinforced construct validity of the tests. Regardless
of the other two interviewees who argued that the tests did not measure their ability in mastering vocabulary, it could be concluded that the tests actually
covered the construct validity. PLAGIAT MERUPAKAN TINDAKAN TIDAK TERPUJI
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In general, the researcher found that the students had positive perceptions on the validity of the test. They considered those three aspects of validity, namely
content validity, face validity and construct validity had been covered by the tests. More to the point, the researcher would present the discussion of each aspect of
validity further. The first aspect is the students’ perceptions on the content validity of the
test. “A test is said to have content validity if its content constitutes a representative sample of the language skills, structures, etc. with which it is meant
to be concerned” Hughes, 1989: 22. This claim meant that the test would have content validity if only it was relevant to the language skill concerned and
accurate to measure what was supposed to measure. Rooted in the data analysis acquired from both instruments, the questionnaire and interview, most of students
implied that the weekly tests had covered the content validity. To be detailed, the researcher found that 98 students argued the material of the tests really
represented the section they had to study. In addition, there were 71 students stating the tests results described their performance in mastering vocabulary.
These findings had also been verified by the results of interview. There were five out of six interviewees confessing that the test material really represented the
section they had to study. Hence, the researcher came to a conclusion that the tests contained the content validity since the tests were relevant, accurate, and
meaningful to measure what were supposed to measure. The second aspect is the students’ perceptions on the face validity of the
test. The researcher discovered that largely the students of Vocabulary I class PLAGIAT MERUPAKAN TINDAKAN TIDAK TERPUJI
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affirmed that the tests had covered face validity. In the questionnaire, it was described that 88 of students acknowledged the instructions of the tests were
clear. Due to time allocation of the test, 67 students confirmed that they were able to do the tests in the allotted time. The test instruction and time allocation
were essential to judge whether the test contained face validity or not. Those two aspects established how the test looked like. “A test is said to have face validity if
it looks as if it measures what it is supposed to measure” Hughes, 1989: 27. According to Hughes, how the test looks like is indispensable. He added that a test
which does not have face validity may not be accepted by students, teacherslecturers, education authorities or employers. Based on the results of the
questionnaire, the researcher concluded that the tests really have face validity. Above all, from the interview conducted, the researcher found that all
interviewees confessed the clarity of the tests instructions. Thus, it is clear that actually the tests have covered face validity as one important aspect of validity.
Having been clear with the face validity of the tests, the researcher then would discuss the construct validity of the test.
The third aspect of validity discussed in the research is construct validity. Hughes 1989: 26 claimed that “a test, part of a test, or testing technique is said
to have construct validity if it can be demonstrated that it measures just the ability which it is supposed to measure.” The word ‘construct’ here referred to the
underlying ability which was hypothesised. Thus, the vocabulary test would have construct validity if only it demonstrated the ability of mastering vocabulary
items, not other abilities like reading comprehension or structure. PLAGIAT MERUPAKAN TINDAKAN TIDAK TERPUJI
51
The researcher found that in general, the students implied the tests were able to measure their ability to master vocabulary items and encourage them to
master a number of vocabulary items as well. To be detailed, there were 77 students stating the tests measured their ability to master vocabulary items.
Moreover, the result of the interview also supported this finding. Student A, student B, student D and student F affirmed that the tests indeed measured their
ability in mastering vocabulary items. In addition, 98 students in the class argued the tests encouraged them to master a number of vocabulary items too. It
could be concluded that truly the weekly tests had covered construct validity, too. Accordingly, as the weekly tests covered those three aspects of validity, namely
content validity, face validity and construct validity, the researcher then confirmed that actually weekly tests were considered valid.
Having discussed the students’ perceptions on the validity of the tests, the researcher would discuss the students’ perceptions on the reliability of the tests.
“A test is considered reliable when it gives the same results every time it measures if it is used under the same conditions, measures exactly what it is supposed to
measure not something else, and should be practical to use” Brown 1996: 185. Therefore, in the following part, there would be further discussion about the
reliability of the tests.