What's Magical About the Rule-of Two for Constructing C-Tests?

Abstract

C-tests have been suggested to be the best in the family of tests of reduced redundancy. They are claimed to be theoretically and empirically valid and reliable measures of language ability. A C-test contains four to six texts and a total of 100 items. It is constructed according to the rule-of two, which involves deleting the second half of every other word beginning from the second word of the second , sentence. This study investigates five versions of a C-test and a standard cloze test with 340 Iranians majoring in English. The C- tests were constructed with three different deletion starts and two different ratios. The results show that there is nothing magical about the rule-of two. Other deletion rates and deletion starts yield more or less similar results. The paper concludes with suggestions for improving the C-test.