Mapping the Human Development Index (HDI) in Indonesia. The criteria used are the Human Development Index (HDI). The mapping results show that Indonesia is still far behind compared to countries in ASEAN [1] . This condition is of concern to the government and education managers to try to improve the quality of education.

According to Article 1, Paragraph (1) of Law No. 20 of 2003 regarding the national education system, education is a deliberate and organized endeavor aimed at fostering an environment and processes for learning, enabling students to actively cultivate their capabilities in religious and spiritual aspects, self-discipline, personality, intelligence, moral excellence, and the essential skills required for their benefit, as well as for the betterment of society, the nation, and the state. This law can expand opportunities for all people to obtain education and the implementation of education in Indonesia must also be quality oriented. The quality of education in question means having competitiveness not only at the national level but also internationally, so the quality standards set must also apply internationally.

The future education system of the Indonesian nation is education that will lead the current generation to become the golden generation of Indonesia in 2045. Exactly in 2045, Indonesia will be 100 years free from the shackles of colonialism. In that year, Indonesia hopes to have a gold generation that can build the nation in a better direction [2]. Islamic education must be able to plan, organize, apply, and develop the potential of students in terms of student acceptance (input), the learning process, and student output.

The formal initiatives to enhance the quality of national education commenced with the issuance of Minister of National Education Regulation No. 63 of 2009, which established the education quality assurance systems. One of the significant factors encouraging the quality assurance movement in the basic education environment is the SPMI program managed by LPMP. Implementing an education quality assurance system involves enhancing the results of quality fulfillment, elevating targets that have not been met, refining discoveries, addressing potential areas for improvement, and establishing additional quality objectives. This ensures that each aspect is systematically monitored, corrected, and improved to enhance overall school quality [3] .

Three factors are causing the low quality of education, namely: first, national education policy and implementation uses an educational production function approach or inconsistent analytical inputs. Second, the implementation of education is carried out centrally. Third, the role of the community, especially parents, in providing education is very minimal [4] .

In fact, at the national level, the quality of education in Indonesia, particularly at primary and secondary levels, falls short of expectations. The findings of the national education quality mapping in 2014 revealed that merely approximately 16% of educational institutions met the National Education Standards (SNP). The majority of educational institutions fail to meet these standards, with some still not meeting the Minimum Service Standards (SPM) [5] .

Formal education, whether managed by the state or private sector, is required to carry out quality assurance externally through the School Accreditation Body, as well as internally by the school itself, to realize how to implement the quality that has been stated in the school's accredited status, while the areas that must be standardized following the provisions of the BSNP, or exceeds it, while carrying out the specified standards is done through the creation of standard operating procedures (SOP) [6].

Firmansyah (2021) states that education as a service provider for customers, therefore meets and exceeds customer needs and desires, it is important to clarify whose needs and desires must be satisfied [7]. However, understanding how to implement quality that is accepted by consumers is not easy. This is because the quality of education is created through a process, which is then handed over to stakeholders according to the desired quality. Most of the quality is provided during the interaction process between consumers and there is personal contact with the service provider.

Muhammadiyah is widely known as a tajdid or renewal movement, researchers categorize Muhammadiyah as a modern Islamic movement. Muhammadiyah's renewal is strong in terms of religious practices, social, health and education. For example, straightening the direction of the Qibla, establishing orphanages, and health services, and establishing schools [8]. As stated by Abdul Munir Mulkhan, many Muhammadiyah educations are superior in the eyes of the public [9]. The issue of education and teaching became the main concern of Muhammadiyah with the formation of a body called the Muhammadiyah Teaching Leadership Council on July 14, 1923 [10].

The Kottabarat Muhammadiyah College (PMK) was born in 2000, namely the beginning of the Special Program (PK) class at Muhammadiyah 1 Ketelan Elementary School. Only in 2003/2004 did the PK class stand on its own and move to Kottabarat. The process of moving from SD Muhammadiyah 1 Ketelan to Kottabarat was difficult and winding, quite a few parents were against it and felt dissatisfied with the new environment.

PMK cannot be separated from the existence of the Kottabarat Mosque, which at that time built a school building, at the same time SD Muhammadiyah 1 Ketelan opened Special Program (PK) classes, namely in 2000/2001. There was a discussion between the Leadership of the Basic Education Council and the Head of the Takmir of the Kottabarat Mosque about the use of the building to the north of the mosque. In short, an agreement was found to use the building to replace the PK class in Ketelan. The basic framework for educational development at the Kottabarat Muhammadiyah College is integrated with mosques and is a prominent characteristic [11]. Kottabarat Muhammadiyah College grew and succeeded in starting four (4) institutions, namely Muhammadiyah Special Program (PK) Elementary School in 2000, PK Muhammadiyah Middle School in 2010, Aisyiyah PK Playgroup and Kindergarten (KB-TK) in 2012 and SMA Muhammadiyah PK in 2016.

The term PK at the Kottabarat Muhammadiyah College does not indicate the learning phenomenon of children with special needs and is also not a reversal of the 70%: 30% curriculum composition. The term PK is originally used to differentiate in such a way from the existence of regular classes at SD Muhammadiyah 1 Ketelan. The initial specificity framework developed by Prof. Mochammad Sholeh Y.A.I, Ph.D. succeeded in compiling and patenting a sharia curriculum. Derivatives of the Sharia curriculum and textbooks gave birth to a unique learning model, namely "the productive teacher learning model, students learn independently under the guidance of their parents". In short, this Sharia curriculum is what characterizes the Kottabarat Muhammadiyah College [11] .

As an Islamic institution that has many members and branches throughout Indonesia, Muhammadiyah has many charitable efforts in various fields of life. In the social sector, this institution manages 309 orphanages and nursing homes. Likewise, in the health sector, there are 311 business charities, consisting of hospitals. In the economic sector, Muhammadiyah has several types of businesses such as People's Credit Banks (BPR), Bait Al-Tamwil (BTM), Muhammadiyah-Owned Enterprises (BUMM), and Muhammadiyah Cooperatives, totaling 936 charities.

The field of education in Muhammadiyah organizations is proven by the number of Muhammadiyah schools that have been established in almost every corner of the country and at the international level. Muhammadiyah's charitable efforts in the field of education: TK/TPQ, the number of Muhammadiyah TK/TPQ is 4623. SD/MI, the number of Muhammadiyah SD/MI data is 2604. SMP/MTs, the number of Muhammadiyah SMP/MTs is 1772. The number of Muhammadiyah SMA/MA/SMK is 1143. Muhammadiyah Colleges, the number of Muhammadiyah Colleges is 172.

In Surakarta, the Muhammadiyah manages 25 elementary school-level educational institutions, 10 SMP/MTs, and 10 SMA/K/MA. In the 2020/2021 academic year, the number of elementary school students is 7,134, SMP/MTs are 2,671 and SMA/K/ MA is 2,237, so the total is 12,042.

Objectively, the quality of Muhammadiyah education has a very diverse range of variations. Among the thousands of Muhammadiyah schools, there are several schools whose quality can be proud of. On the other hand, there are still many of these schools which are of low quality and whose conditions are quite worrying. Based on this, it is necessary to guarantee the quality of education so that there is quality standardization in the management of education at Muhammadiyah so that it can produce quality output [12], [13] .

Quality assurance is a quality management effort carried out by internal school parties, to provide guarantees that all aspects related to educational services provided by a particular institution or educational unit can reach a certain quality standard. Implementation of education quality assurance is necessary because it takes into account the following: 1. The quality of education varies between schools/madrasas and between regions, 2. Each student is entitled to access highquality educational services, 3. Continuous improvement of the quality of schools/madrasas is a necessity, and 4. Low quality of education will cause low human resource competitiveness [14] .

If Muhammadiyah schools receive quality assurance, Muhammadiyah schools will undoubtedly remain schools that are popular with the public. The high public interest in Muhammadiyah schools and the public's trust in Muhammadiyah educational institutions means that the demand for quality Muhammadiyah educational institutions will be even higher [15]- [17] .

Based on the above background, researchers are interested in researching: 1) strategies for improving the quality of education through internal quality assurance at Muhammadiyah Middle School of Special Program at Kottabarat, Surakarta. (2). impact of internal quality assurance at Muhammadiyah Middle School of Special Program at Kottabarat, Surakarta.

Internal quality assurance (IQA) plays a crucial role in enhancing education quality by systematically monitoring and improving the performance of educational institutions. IQA strategies focus on establishing standards, evaluating processes, and fostering a culture of continuous improvement to ensure the alignment of educational outcomes with the institution's goals and external expectations. These strategies include curriculum development, teacher competency enhancement, effective assessment systems, and stakeholder engagement [18]-[20] .

Research highlights that institutions with strong IQA frameworks are better equipped to adapt to changes and maintain high standards of academic and administrative quality. Additionally, internal audits, feedback mechanisms, and data-driven decision-making are essential components of IQA, enabling institutions to identify weaknesses and implement corrective actions. In the context of global competitiveness and accreditation requirements, internal quality assurance is indispensable for educational institutions striving to meet national and international benchmarks while catering to the diverse needs of students and society [21]- [23] .

This research used a qualitative approach applying a multi-site study, across educational levels. Data sources were collected from natural settings and directly analyzed to find strategies for improving the quality of education through internal quality assurance at Muhammadiyah Middle School of Special Program [24]- [26] .

Following the type of qualitative research, data collection was carried out by using 3 (three) techniques encompassing: (1) participant observation, (2) in-depth interviews, and (3) study documents [27] .

The steps of qualitative data analysis according to Miles and Huberman in the form of activities carried out were data collection, data reduction, data presentation, conclusion, and verification [28].

The table above explains several aspects, especially from qualitative research as illustrated above.

According to the Indonesian Dictionary, quality is related to the good and bad of an object; level; or degree, for example, intelligence, intelligence, and so on [29] . Edward Sallis put forward the concept of quality in terms of "Quality is often described as meeting or surpassing the needs and desires of customers, a concept referred to as quality in perception. It's commonly understood that quality is subjective, meaning it is perceived differently by individuals. This perspective emphasizes the significance of consumer judgments in defining quality. Any institution disregarding this definition does so at its own risk, as it's ultimately the consumers who determine what constitutes quality" [30] .

From this understanding, it can be concluded that quality is a measure to express the essence of something in the form of an ideal standard to be achieved in a process. Apart from that, it is clear that quality is always focused on the customer so that products are designed and produced and services are provided to meet customer desires. Because quality refers to everything that determines customer satisfaction, a product produced can be said to be of quality if it meets the customer's wishes, can be used well, and is produced in a good and correct way [31]-[33] .

The system for assuring the quality of primary and secondary education is a unified entity comprising interconnected entities, policies, and procedures governing all efforts aimed at enhancing the quality of primary and secondary education in a systematic, deliberate, and enduring fashion. The primary and secondary education quality assurance system strives to ensure that standards are met across primary and secondary education facilities in a systematic, comprehensive, and enduring manner. Its objective is to foster an autonomous culture of quality within educational establishments. The role of the education quality assurance system is to oversee the execution of education by these establishments to achieve the goal of delivering quality education [34]–[36].

The quality assurance system for primary and secondary education comprises two main components: the Internal Quality Assurance System (SPMI) and the External Quality Assurance System (SPME). The Internal Quality Assurance System is established within the educational institution and involves participation from all its components. On the other hand, the External Quality Assurance System is implemented by government bodies, local administrations, accreditation agencies, and educational standardization institutions [37]–[39].

Education Quality Assurance serves as a methodical, cohesive, and enduring mechanism aimed at ensuring that every aspect of the education delivery process meets predefined quality standards. In this context, the Primary and Secondary Education Quality Assurance System (SPMP Dikdasmen) functions as a cohesive entity comprising interconnected organizational structures, policies, and procedures. Its purpose is to oversee all endeavors aimed at enhancing the quality of primary and education, ensuring they interact systematically, with deliberate planning, and in a sustainable manner [40]-[42] .

Quality assurance in education must be carried out from the beginning of the educational process. Schools must implement a quality management system to ensure the realization of quality in every stage of school activities, namely input, process, and output for school management. If errors occur in the input and education management process, corrections must be made immediately so that the education process and results become more optimal. If the educational process is not carried out optimally and follows the National Education Standards (SNP), the quality of graduate competence cannot be guaranteed [43]–[45].

The stages of the Internal Quality Assurance Mechanism at Surakarta Special Program Muhammadiyah Middle School apply the Deming cycle, namely the PDCA cycle, namely, Plan (planning), Do (implementation), Check (evaluation), and Act (follow-up). This PDCA stage is still carried out in the education quality assurance system and must be developed and implemented by Surakarta Special Program Muhammadiyah Middle School in carrying out the education process [46]–[49].

The implementation of quality assurance at Surakarta Special Program Muhammadiyah Middle School is as follows:

a. Planning

The planning stage begins with determining the quality standards to be achieved. These quality standards refer to the SNP set by the government. Efforts to fulfill the SNP are carried out in stages according to the school's capabilities. In this planning stage, education quality mapping is also carried out through School Self-Evaluation (EDS) to determine the gap between actual conditions and the quality standards that have been set. After knowing the problems, the next step is for the school to make a quality fulfillment plan using a priority scale for achieving quality first. A quality fulfillment plan is made by involving stakeholders to foster joint commitment in implementing the plan that has been made [50] .

Quality mapping at Muhmmadiyah Middle School of Special Program Surakarta was carried out by analyzing school quality report cards or what is called School Self-Evaluation (EDS), to find out the extent of the school's development before the implementation of SPMI. The planning for improving quality at Muhmmadiyah PK Surakarta Middle School was formulated by the entire School Quality Development Team (TPMS) with the guidance of the Education Quality Assurance Institute (LPMP). In the planning process, several stages were carried out, starting from redetermining the school's TPMS to become SPMI TPMS, and carrying out an EDS analysis and SWOT analysis. The implementation of quality improvement at this Middle School is carried out following the results of the EDS, namely focusing on improving the four National Education Standards which are included in academic standards (Content Standards, Process Standards, Assessment Standards, Graduate Competency Standards) [51]- [53] .

Quality planning or quality improvement again in Monitoring and Evaluation of quality improvement at SMP Muhmmadiyah PK Surakarta is carried out by the Monitoring and Evaluation Team. Supervise every implementation of internal quality improvement in SMP and evaluate implementation that needs to be improved, including analysis of similarities between the previous year's quality report card and the current year's quality report card. In this way, we can see the progress of implementing SMPI in schools. And re-plan what standards are not following the targets or planning national education standards that have not been corrected [54]–[56].

b. Actuating

The next activity is implementation, namely carrying out quality fulfillment programs or activities following the quality fulfillment plan created.

c. Evaluation

Implementation of the quality fulfillment plan must be followed by monitoring and evaluation activities to ensure that activities are carried out following the plan.

d. Follow Up

The next step is to carry out follow-up actions based on the results of monitoring and evaluation.

This research results in three important findings. First, the strategy to improve the quality of education through internal quality assurance. Internal quality assurance at Muhammmadiyah Middle School of Special Program at Kottabarat Surakarta is a step prepared by the education unit that aims to control the quality and improve the quality of education, referring to government regulations and the peculiarities or characteristics of Muhammadiyah education. The steps in ensuring educational quality are quality mapping, planning, organizing, implementing evaluating, and following up. Second, the impact of implementing internal quality assurance at Muhammmadiyah Middle School of Special Program at Kottabarat Surakarta is to increase academic and non-academic quality. Increased public trust in schools and better services to students and parents.

Thank you to the rector of the Technology and Health Science Institute of PKU Muhammadiyah Surakarta, Indonesia, and the rector of the Mamba'ul 'Ulum Islamic Institute of Surakarta, Indonesia for supporting this research

The author contributed equally to the main contributor to this paper, some are as chairman, member, financier, article translator, and final editor. The author read and approved the final paper.

The author declares no conflict of interest.