Physical education (PE) helps students develop motor, cognitive, and social skills. One of the materials taught is the game of table tennis. This game not only trains technical skills but also trains concentration, improves the development of eye-hand coordination, and balance functions (González-Devesa, Sanchez-Lastra, Pintos-Barreiro, & Ayán-Pérez, 2024; Novikova & Burlaka, 2023). In learning table tennis, the development of students' skills needs to be evaluated. Ideally, every PE teacher needs to design instruments based on the psychomotor, cognitive, and affective skills being assessed. Moreover, it is important to understand the development and use of valid and reliable assessment instruments (Sailer et al., 2021).

Unfortunately, observations in the field show various problems in applying evaluation in physical education learning, especially in table tennis material. Many teachers still use conventional assessment methods that are subjective because they do not have clear standards for assessing students' skills, such as observation without using rubrics or structured assessment indicators. In addition, the lack of understanding of the validity and reliability of assessment instruments causes inconsistent evaluation results and inaccurate assessments that hinder the objective mapping of students' abilities. Matthew (2024) states that a valid instrument can provide an accurate picture of learner achievement and help teachers provide comprehensive feedback to improve learning and optimal learner skill development.

There has been much research on the evaluation and development of assessment instruments in table tennis games (Faber, Koopmann, Büsch, & Schorer, 2021; Utama, Tomoliyus, Sridadi, Widodo, & Ariani, 2023). However, of the few studies found, no validated and reliable assessment instrument has been developed explicitly for evaluating junior high school students' forehand and backhand serve skills in educational settings. Most existing studies focus on athletic performance. Meanwhile, assessment instruments in education are indispensable for teachers in identifying whether students have realized the lesson objectives (Oppi & Eisenschmidt, 2022; Van Geel, Keuning, & Safar, 2022). Polenghi (2024) states that the results of assessment instruments provide insight into the effectiveness of teaching methods and curriculum design. Therefore, this study fills a significant research gap by providing a psychometrically tested instrument tailored for school-based physical education.

Based on the information obtained and answering the previously described gaps, this research aims to develop a table tennis game skill assessment instrument by limiting the focus to junior high school students. The instrument developed will adjust the dominant movements of students as well as the selection of specific assessment criteria, with implementation procedures and language that is easy to understand and clear. In addition, this research will place special emphasis on the validity and reliability of the instrument. This research aims to provide reliable references and tools for teachers to evaluate and provide comprehensive assessments related to physical education.

The results of content validity are obtained through an expert assessment process, carried out using the FGD (forum group discussion) method, with an average value of 81.3% (valid / can be used without revision) based on the results of the FGD three indicators are used to assess the ability of table tennis serve motion of junior high school students. Discussion points include content suitability, accountability, and transparency. The results can be seen in Figure 2.

Based on Figure 2, the following FGD results were analyzed for each component: 1) Appropriateness, with an eligibility score of 81% (valid); 2) Accountability, with a score of 79% (valid); 3) Transparency, with an eligibility score of 81% (valid).

Based on Table 1, the instrument's reliability level using the retest method has been shown. The first experiment (x) and the second experiment (y) were conducted on 40 students limited to the junior high school level in Malang Raya, with an age range of 13-15 years, and the results show numbers above the threshold of 0.70 so that the instrument that has been developed can be declared reliable.

Based on the results of proving empirical validity, Table 2. Using the Pearson Product-Moment correlation approach with a significance level of 0.05, the forehand serve variable has a calculated R-value of 0.456> r-table 0.312, so the table tennis skill instrument on that variable is declared valid. The backhand serve variable obtained a calculated R-value of 0.352> r-table 0.312, so the table tennis skill instrument on that variable was declared valid.

Teachers are indifferent to assessment and consider it to have no more importance than administration. This is exacerbated by a large workload that makes it difficult for teachers to compile and test assessment instruments in depth. As a result, most teachers still use conventional assessments without using instruments that have been tested for validity (Andarage, Fernando, Lokuarachchi, Athuluwage, & Wijewickrama, 2023). Moreover, the large number of class groups is a challenge for teachers in assessing and evaluating. Therefore, the instrument developed is here to answer these problems. This instrument can be implemented by PE teachers when carrying out formative assessments, or teachers can easily observe and assess. At the same time, students practice basic table tennis techniques. The minimum number of indicators and simple language selection will also help him make observations and assessments. Whereas the purpose of the instrument is as a tool in measuring student learning achievement, it is also important to help educators examine the extent to which students can achieve curriculum goals (Pratama & Dewi, 2023). Not only understanding the material taught, but also developing the expected competencies and skills.

The study of the development of process and outcome skill assessment instruments in table tennis learning forehand and backhand service material is expected to provide exceptional convenience for educators in physical education subjects. An instrument tested for validity will be able to measure what should be measured, while a reliable instrument guarantees a consistency of measurement results in various conditions. Moreover, the results of measurement and evaluation become the basis for making decisions about teaching strategies and methods and provide helpful feedback for students' academic progress (Faiz, Putra, & Nugraha, 2022; Walters, Maclaughlin, & Deakin, 2023). Thus, using instruments that meet both criteria will improve the quality of assessment.

The correlation coefficient shows a minimum threshold based on the results of proving the empirical validity of the forehand and backhand tests. This is related to the ability of students to respond to external stimuli, where the feeder throws the ball and students are required to respond to the stimulus quickly and accurately. The stimulus in question is the ball's speed, the bounce's height, and the ball's rotation. Research from Kurniawan & Rangkuti (2020) revealed that having good hand-eye coordination also leads to reasonable accuracy in table tennis games. Alternatively, the inverse paradigm of children with poor eye-hand coordination can be seen in their ability to perform stroke techniques in table tennis (Suryati, Triansyah, Hidasari, & Haetami, 2020).

The selection of topics is based on several benefits that will be useful for students' future development. This means that the essence of table tennis lessons is not merely about the sport itself, but holistic development, such as physical, mental, social, and emotional skills (He, 2024). An investigation showed that regular table tennis can help cardiovascular fitness (Zaferanieh et al., 2021). Other findings reveal table tennis as a fun and accessible activity to help improve children's health and limit sedentary behavior (Pradas, Ara, Toro, & Courel-Ibáñez, 2021).

Based on the test results and research findings, it can be concluded that the assessment instrument for forehand and backhand serve skills in table tennis games for junior high school students has met the validity and reliability criteria. This shows that the instrument is suitable for teachers as an objective and consistent measuring tool in evaluating basic table tennis skills in students. Further research with a larger number of subjects and optimization of digitization-based features needs to be carried out to provide a more representative picture of the diversity of student abilities, facilitate the administration process, and improve the efficiency of the assessment.

The research team would like to thank the Universitas Negeri Malang and Active Movement Indonesia for providing funding so that this research can be completed.

All data supporting the findings of this study are included in the article and its supplementary materials. Additional datasets are available from the corresponding author upon a reasonable request.

This research was funded by the State University of Malang.

The author hereby declares that this research is free from conflicts of interest with any party.