This study investigated to what extent the scores of two English tests are correlated to each other, namely, the English test of the "Common Test for University Admissions" (Common Test, henceforth) in Japan and the "TOEIC Bridge", a commercially available English test developed by "Educational Testing Service" (ETS) that measures four skills of listening, reading, speaking, and writing. Moreover, this study examined to what extent the two tests' constructs overlap from the viewpoint of L2 competence. In total, 128 university freshmen and high school seniors took the Common Test at the official venues and also the TOEIC Bridge at the researcher's university (n = 92) or at home (n = 36) a few months later. Results indicated that the scores of the corresponding skills are moderately correlated to each other across the two tests (Reading = 0.548; Listening = 0.646; Total = 0.732). Confirmatory factor analyses demonstrated that the degree of data fitting of the three models of test constructs (unitary, correlated skills, correlated tests) was statistically similar to each other. On the basis of substantive and statistical results, however, we claim that the correlated skills model should be chosen as the best-fit model and, consequently, that the productive skills should be measured in addition to the Common Test.