“…Based on the review of the 31 identified studies, 16 papers conducted assessments to evaluate the accessibility of OER, while the 15 remaining papers did not conduct any assessment. Specifically, to assess the accessibility of OER, three different methods were used, as shown in Using manual evaluation method Questionnaires Avila Caruso & Ferlino, 2009;Mulwa et al, 2016;Navarrete & Luján-Mora, 2015a;Navarrete et al, 2019;Navarrete & Luján-Mora, 2018;Sanchez-Gordon & Luján-Mora, 2016 No assessment N/A Coughlan et al, 2016;Hejer et al, 2017;Iniesto and Rodrigo, 2018;Iniesto & Rodrigo, 2016;Iniesto et al, 2017;Iniesto et al, 2019;Kourbetis & Boukouras, 2014;Kourbetis et al, 2016;Morales and Benedi, 2017;Moreno et al, 2018;Navarrete et al, 2016;Politis et al, 2014;Sanchez-Gordon & Luján-Mora, 2015;Yalcinalp & Emiroglu, 2012;Zervas et al, 2014 aDesigner, used by Iniesto and Rodrigo (2014) and , aimed to simulate the use by people with visual disabilities in order to help the designer assess the extent to which a given content is accessible to users with that particular disability. Finally, manual assessment is mostly based on users' questionnaires (Avila Caruso & Ferlino, 2009;Mulwa et al, 2016;Navarrete et al, 2019;Navarrete & Luján-Mora, 2015a;Navarrete & Luján-Mora, 2018;Sanchez-Gordon & Luján-Mora, 2016).…”