**2. The development of multi-tier instrument: the chronological perspective**

#### **2.1 Two-tier instrument: The milestone of multi-tier instruments**

The use of multi-tier instruments in science education was initiated by Treagust [15], investigating students' unscientific understanding in particular. The example of the two-tier instrument applied in such an instrument's initial development is provided in **Figure 1**.

The first-tier at the initial format portrayed in **Figure 1** consists of a multiplechoice question (MCQ ) with only two options (one correct answer and one incorrect answer). This MCQ with a two-options format is quite uncommonly applied in science assessment, common in at least four options. The second tier consists of four statements covering the reasons for students' answers to the first-tier. The four reasons consist of one valid or scientific reason and three wrong or unscientific reasons. The combination of students' incorrect answers and the incorrect reason is the basis for revealing students' unscientific understanding or misconception. All incorrect reasons in the reason tier are composed based on students' actual unscientific understanding obtained from preliminary tests, interviews, and literature. The next generation of the two-tier instrument has employed a more standard MCQ in the first-tier, as depicted in **Figure 2**.

This two-tier format has been applied to investigate students' conception in many science education research including Tan et al. [16] in inorganic chemistry, Tuysuz [17] in Separation of Matter, Griffard & Wandersee [18] in Photosynthesis, Chandrasegaran et al. [9] in Chemical reaction, Peterson et al. [5] in covalent bonding, Tyson et al. [19] in chemical equilibrium, Adadan & Savasci [20] in solution chemistry and many others.

*The Multi-Tier Instrument in the Area of Chemistry and Science DOI: http://dx.doi.org/10.5772/intechopen.100098*


#### **Figure 1.**

*Example of the two-tier instrument developed by Treagust [15].*

#### **Figure 2.**

*Example of the next generation of the two-tier instrument developed by Chandrasegaran et al. [9].*

#### **2.2 Three-tier instrument**

After being applied in many studies, science education researchers realized that the two-tier instrument has deficiencies. Students selected the correct answer and correct reason randomly without holding a scientific reason to the relevant concept on certain occasions. The role of guessing and the actual unscientific understanding are difficult to be differentiated in a two-tier instrument [21, 22].

To overcome the two-tier instrument's drawback, a three-tier instrument was developed with the additional confidence rating tier, as shown in **Figure 3**. The third-tier requires students to state whether they are sure or unsure of their answer and reason. A correct answer and reason with a sure expression imply a scientific understanding. Meanwhile, an incorrect answer and reason with a sure expression imply an unscientific understanding or misconception. An incorrect answer and reason with an unsure expression imply that the incorrect answer is not a result of


#### **Figure 3.**

*Example of a three-tier instrument developed by Arslan et al. [23].*

misconception or unscientific understanding; instead, it lacks knowledge or guessing. This aspect distinguishes the three-tier format and the previous format. The same pattern of the three-tier instrument portrayed in **Figure 3** has been used in the following studies [11, 24, 25].

The subsequent development of a three-tier instrument utilized a more flexible confidence rating with a broader range of confidence, as displayed in **Figure 4**. This pattern seems to have been influenced by the standard confidence rating scales applied in many four-tier instruments that had been published before this three-tier work was carried out.

#### **Figure 4.**

*Example of a three-tier instrument developed by Aydeniz et al. [26].*
