**3. The procedure in developing a multi-tier instrument**

Treagust [15] proposed the two-tier instrument development is the fundamental development of the next generations of multi-tier instruments, including three-tier and four-tier instruments. Treagust [15] employed ten steps with three board categories in developing a two-tier instrument. The first four steps are named *defining the content*. Steps 5, 6, and 7 are named *obtaining information about students' misconceptions*. The last three steps are named as *developing a diagnostic test*. The steps are:


When we developed a four-tier instrument in the area of chemical kinetics named FTDICK [7], we simplified the procedure to be six steps as the following. This procedure is applicable to developing multi-tier instruments.
