When using True/False questions to test students, there are a few assessment-related issues to keep in mind.
The math makes these types of items the least useful in some ways. Students have loved these questions for years, because regardless of whether or not they know the material, they have a 50 percent chance of guessing correctly. Because of this, these question types are probably not the best way to ask things in high-stakes types of tests. There are, however, ways to compensate for this problem, such as only awarding points for those reaching a minimum score.
On the other hand, these questions are simple to write. They only require, at minimum, a simple statement. Instructors wishing to simply see if a student is aware of a basic piece of information can create a list of them in just a few minutes.
Now, even though these types of items are not the best for summative assessment, they do hold some value for formative testing and self-assessment.
In formative testing, we are concerned with teaching and instruction. These kinds of tests can help teachers guide students and help them determine student weaknesses or areas i which the teacher can provide additional instructions. If a teacher notices a large number of students are having trouble with the information being taught, the teacher can do several things: look at the way the material is being presented and see if there is a better approach to take with the class, give review sessions for those needing it, assign more time to the skill in question, or something else that will likely improve the situation.
By creating True/False tests in Moodle, which are fast and easy to produce, it is simple to create more formative tests, giving teachers an even easier way of checking on student progress. In addition, the use of the shuffle question and random question functions, which will be looked at later, allow any questions from the bank to be used. By creating a category based on a specific skill, you can load it with any questions you have based around that skill and Moodle will randomly generate tests for you. Assuming you are using the same types of questions focused on the same skill, you will be able to use the Quiz reporting tool to help you see any student improvement in that skill area.
Self-assessment is about learning. It is about finding which areas you are weak in and working on improving them. Teachers that use this kind of activity are attempting to make their students become active and independent learners. Using True/False questions is a useful way to help students with this type of assessment. If you prepare a review quiz in Moodle using True/False question types, students can quickly see what they know and don't know. This knowledge will help dedicated learners decide how best to spend their time and energy.
Even with the ability to compensate somewhat for guessing, with a 50 percent chance of guessing the correct answer at random, True/False itself is not the most effective item type available. In addition, students have no choice but to guess even if they don't know the answer. In fact, even if they don't want to answer because they know they don't know the answer, they are forced to either avoid clicking on either response option, or if they accidentally do click on an answer, make a guess. This situation is not all bad though, because there are some who argue that this process will force students to think carefully before selecting an answer. The problem is that there is no way to remove a response completely once one has been selected. An inclusion of a feature that would allow students to 'pass' if they didn't want to answer, I feel, would be a great addition. It could help in assessment and validity issues related to testing in Moodle.