Acid-base topic materials oriented towards higher-order thinking skills/HOTs based instruments Available to Purchase

The results of the analysis of formative and summative test items oriented to HOTs in several high schools in East Java, Indonesia, in the 2013-2017 academic year were 9% to 13.29%. In the same year the number of HOTs-oriented items on the national chemistry exam for high school students was around 22.5%. It can be concluded that the application of HOTs-oriented chemistry questions is still low. Therefore, it is necessary to develop an assessment instrument to support it. The chemistry topic chosen was acid-base, a chemistry topic in the high school curriculum. The chemistry concept of the acid-base topic is interrelated, so it becomes a suitable topic to improve students’ higher order thinking skills. The method used in this research to develop the instrument is the Design and Development Research method. The research was carried out in four stages, namely analysis, design (planning), development, and evaluation. Content validity of the HOTS instrument was examined by two expert lecturers, and the empirical validity was obtained from 118 high school students. The value of the percentage of instrument feasibility based on the results of content validation is categorized as very feasible (93.94%). The results of the 40 items empirical validation showed that there were 28 valid items and 12 invalid items with Pearson correlation range of -0.314 to 0.780. The item discriminating power resulted in 2 very good items, 9 good items, 14 satisfactory items, 11 items which are less than satisfactory, and 4 not satisfactory items. The number of difficult and moderate questions each amounts to 20 items. The items that meet the standard of validity, discriminating power, and difficulty index are 28 items with a high reliability of 0.761. That results indicate that the HOTS assessment instruments developed in this study can be used to measure students’ HOTS.