Aaccessibility and inclusion in education represent key aspects for sustainability development ^[4]. According to the 2030 Agenda for Sustainable Development, the fourth Sustainable Development Goal (SDG) is Education. This goal is ^[5] (i) to “ensure inclusive and equitable quality education and promote lifelong learning opportunities for all” by providing access to affordable and quality technical, vocational, and tertiary education, including universities (Target 4.3); and (ii) to ensuring equal access to all levels of education and vocational training for the vulnerable, including persons with disability (Target 4.5). Even some experts and disability advocates agree that all seventeen SDGs and objectives from CRPD are related to accessibility and disability, either directly or indirectly ^[4][6]. According to ^[7], accessibility is also one of the measures of social sustainability. However, accessibility in universities can be complicated in practice since higher education is broadly considered as the most exclusionary educational level ^[8]. Besides that, what is accessible to someone may not be for another person, therefore, it becomes important to analyze not only if certain alternatives are accessible or not, but also understand to whom they are accessible, under what conditions, and for which tasks ^[1].

In this way, student accessibility services (SAS), commonly embodied as offices or units, have emerged during the past three decades in universities intended to achieve truly accessible higher education ^[8]. The office of SAS is also known as the Office for Students with Disabilities, Office of Disability Services (ODS), Student Disability Services, or Office for Inclusive Education. These offices are focused on guaranteeing the full inclusion and participation of university students with disabilities considering their individuality through effective equal opportunities and non-discrimination in academic life. Offices of SAS also promote sensitization and awareness of all members of the university community ^[9].

In general, an office of SAS could be perceived as a way to foster and implement diverse accessible strategies, assistance, and support in favor of students with disabilities ^[10]. The office of SAS is closely related to virtual environments and ICT (Information and Communications Technology). AIn this context, accessible ICT are implemented to empower support to students and faculty with or without disabilities through virtual campus, 3D job simulators, or Open Educational Resources (OERs) ^[11].

These aspects suggest that the establishment of one of these offices in universities could be difficult, especially for those institutions new in the accessibility context, since many factors are involved, such as training, technology, and collaboration ^[8][9]. The successful implementation of accessibility services requires the involvement of the entire university community and its holistic integration with the institution. In t ihis situation, it is evident that there is a need for standardized guidance to mitigate the special educational needs of students with disabilities in structured similar ways at different higher education institutions (HEI) ^[8].

2. Background of SAS

In 1948, the University of Illinois at Urbana-Champaign became the first post-secondary institution to provide a support service program enabling students with disabilities to attend, which evolved during the ensuing years to the current Disability Resources and Educational Services (DRES) at the University of Illinois ^[12]. Currently, DRES is ranked in the Top 10 of the best disability-friendly colleges and universities, sharing the honor with others such as the Department of Disability Resources from Texas A&M, the Office of Accessible Education from Stanford University, Services for Students with disability Office at the University of Michigan, and the Student Disability Services from Cornell University ^[13].

Similar efforts have emerged around the world; for example, in Spain, in 1989 the Universidad Autónoma de Barcelona was the first public university in offering attention services for students with disability and was followed by many others such as the Universidad de Alicante in 1997 and Universidad de Alcalá in 2005 ^[14]. In Mexico, some public universities were pioneers in integrating SAS, including the Universidad Autónoma de México, Universidad Veracruzana, and Universidad Autónoma de Tlaxcala, which offer grants for students with disabilities as part of their services (Becas de discapacidad para entrar en la universidad en México, Universia MX, https://www.universia.net/mx/actualidad/becas-y-ayudas/becas-de-discapacidad-para-entrar-en-la-universidad-en-mexico.html accessed on 20 December 2021).

In this context, a broad aspectstudy to understand the degree of inclusion in Spanish universities revealed some specific objectives to be covered by offices of SAS in HEIs ^[9]:

• Facilitate access to university studies for pre-university students with disabilities;
• Provide information, training, and support to the university community in the effective application of inclusion policies and regulations for people with disabilities;
• Offer resources and academic advice to students with special educational needs derived from their disability;
• Guarantee accessibility to university spaces including virtual information, services, and learning;
• Collaborate with different institutional levels in the university, as well as with external organizations and entities to improve the effectiveness of the services;
• Collaborate and contribute to the labor insertion of students with disabilities and observe contract regulations in favor of people with disabilities during students’ recruitment;
• Promote awareness in the university environment regarding people with disabilities;
• Update knowledge through training programs for those professionals in the public and private sectors who care for people with disabilities.

Similarly, international regulations foster the relevance of student accessibility services by asking universities to attend students’ needs through reasonable adjustments, personal assistance, accessibility awareness and sensitization, faculty training, labor insertion, technical and economic support, accessible environments, and even research on accessibility ^[8][14]. Fundación Universia highlighted the following ideal features of SAS ^[15]:

• The service operates directly as a unit, office, or internal/specific area in the university. Although this is the most common form of operation, it can also be operated through a foundation, or as a shared task between two or more offices or internal areas in the university.
• The office organically depends on a vice-rectory (most common organic structure), management, or another administrative area, or a foundation.
• The office usually integrates multidisciplinary (psychologists, pedagogues, physiotherapists, sign language interpreters, among others) and inclusive (men, women, personnel with disabilities) working groups.
• The office works together with its peers in other universities, other care units in the university itself (for example, psychological care unit), and public or private organizations that work with disabilities.
• The office encourages the voluntary participation of students, recognizing with academic credits their collaboration in support services for people with disabilities at the university.
• The office has a continuous improvement process or an internal evaluation system, which could be owned or based on a quality assurance standard (for example, UNE-EN ISO 9001: 2015 standard).