In this article the effectiveness of open-ended tasks and multiple-choice item tests on students’ achievement in a linguistic course was investigated. To this end, a true-experimental research method with a randomised pre-test–post-test experimental group design was applied. The author had the participants in the two groups actively participate in the classes and they were advised to study in such a way that they would master the content of the course. The only difference between the two groups was that the participants in the experimental group were told that their learning achievement would be evaluated via open-ended item tests and/or quizzes, whereas those in the control group were informed that multiple-choice tests and/or quizzes would be used to measure the knowledge they obtained. To analyse the collected data, an independent samples t-test was run. The results showed that the students who expected and were given open-ended quizzes or tests in their final assessment outperformed those who expected and were given multiple-choice quizzes or tests in their final assessment. The implication drawn from these results is that requiring students to construct their own responses to assessment questions is a more effective way to assist them to master course content than having them do multiple-choice type tasks.