The most important factor of any educational tool's effectiveness is its accessibility to students. Educational aids must be made available to all students within a classroom. For this reason, it may be necessary to have several of the same type of tool. For example, a math teacher who wants to use calculators should have enough on hand for his largest class of the day.
For educational tools to be effective, they must be clearly visible. Chalkboards provide convenient visual platforms from which to observe and copy information. Dry-erase boards use markers, which can easily be wiped away. Electronic boards, or "whiteboards," can link directly to a teacher's computer to display information that can be altered directly or remotely.
Educational tools are most effective when they introduce students to knowledge and skills that prepare them for the real world. Desktop and laptop computers are useful for this purpose, as they can be used to access educational and creative material while familiarizing students with technology.
A large degree of any educational tool's effectiveness lies in the ability of the person using it. Both students and teachers must be familiar with a tool's operation and intended purpose before it can be used effectively. For example, an art teacher who wishes to use a slide projector should be aware that such devices require periodic maintenance and are ideally placed some distance from the screen.
Educational tools are effective when they are generally useful. Syllabi, for example, keep classes focused on a curriculum through organized structure.
Educational tools become effective when they encourage participation from learners. The greater the degree of interactivity, the greater the benefit is to the student. For example, guest lecturers often engage students directly with question-and-answer sessions. Such sessions serve to educate students while sparking their interest in the subject.