In response to the increasing interest in and need for a practical brief measure in language testing, this study explored the properties of an offline short-form test (OSF) versus a conventional lengthy test. From the total of 98 vocabulary items pooled from the Iranian National University Entrance Exams, 60 items were selected for the conventional test (CT). To build the OSF, we created an item bank by examining the item response theory (IRT) parameter estimates. Data for the IRT calibration included the responses of 774,258 examinees. Upon the results of the item calibration, 43 items with the highest discrimination power and minimal guessing values from different levels of ability were selected for the item bank. Then, using the responses of 253 EFL learners, we compared the measurement properties of the OSF scores with those of the CT scores in terms of the score precision, score comparability, and consistency of classification decisions. The results revealed that although the OSF generally did not achieve the same level of measurement precision as the CT, it still achieved a desired level of precision while lessening the negative effects of a lengthy test. The results also signified an excellent degree of correspondence between OSF and CT scores and classification results. In all, findings suggest that OSF can stand as a reasonable alternative for a longer test, especially when conditions dictate that a very short test be used.
