Assessment is an essential component in education process. Traditionally, classroom assessment has had a summative purpose. Summative assessment goal is to evaluate students’ learning at the end of an instructional unit or at the end of the semester to compare it against some standard to assess what has been learned and how well it was learned. It provides information that sums up the learning process. The most common outcome of summative assessment are the grades, which indicate students’ level of knowledge, and the most widely instrument used is the exam.

However, assessment may also serve as a formative function. Formative assessment goal is to continuously gather evidence about learning and teaching process (Heritage, 2007). This evidence is used (i) to give students feedback directly related to task, and to make changes in learning activities students are involved in and (ii) to adapt teaching to students’ needs, helping them to develop skills to learn better and to go forward in their learnings. Formative assessment also promotes active involvement of students in their partners and in their own assessment. Formative assessment contributes to students’ learning, influencing learning process and academic achievement (Weurlander, Söderberg, Scheja, Hult and Wernerson, 2012).

There are many researchers around the world who study student assessment. Their results and conclusions are intended to be extrapolated to the population. However, the belief that what is done in some places can have universal validity is a fallacy. Research results can only be valid if they are obtained or referred to the context where they will be applied. Unfortunately, the student assessment knowledge base is very limited in developing countries.

In Latin America, educational assessment is principally focused on external evaluation to certify the educational level of each country regarding some standards or some rankings (Ferrer, 2006). However, this kind of assessment does not seem to be the most suitable for these countries. This is a territory characterized, among others, by its educational disparity. Gaps between different social strata where educational systems are involved cause these inequalities. (Rivero, 2000). Nevertheless, education itself and the components of the educational process can perpetuate or even intensify these inequities, bringing about differences in students’ learning. (Blanco Bosco, 2009). Therefore, this kind of evaluation based on national measures and international comparisons end up legitimizing differences (Murillo y Roman, 2010).

Previous researches conducted in Latin America about how assessment influences students’ academic achievement, the most remarkable study is the one developed in 2015 by Martinez-Garrido in 8 Latin American countries (Bolivia, Chile, Colombia, Cuba, Ecuador, Panama, Perú and Venezuela) and Spain, with 5722 participants. Results showed that collecting students’ notebooks had an impact of 5 points in Language performance and 7.8 points in Mathematics performance. They also found that feedback provided to students meant an improvement of 2 points in Language performance.

The aim of this research is to:

• Determine the impact that assessment has on Primary students’ academic achievement in Reading and Mathematics performance

Blanco Bosco, E. (2009). La desigualdad de resultados educativos: aportes a la teoría desde la investigación sobre eficacia escolar. Revista Mexicana de Investigación Educativa, 14 (43), 1019-1049. Ferrer, G. (2006). Sistemas de Evaluación de Aprendizajes en América Latina Balance y Desafíos. PREAL Goldstein, H. (1987). Multilevel models in educational and social research. Londres: Charles Griffin & Co. Heritage, M. (2007). Formative assessment: What do teachers need to know and do? Phi Delta Kappan, 89 (2), 140-145. Martinez-Garrido, C. (2015). La investigación sobre enseñanza eficaz. Un estudio multinivel para Latinoamérica. Madrid: UAM Ediciones Murillo, F.J. y Martínez-Garrido, C. (2013). Impact of Homework on Academic Performance. A Study of Iberoamerican Students of Primary Education //Incidencia de las tareas para casa en el rendimiento académico. Un estudio con estudiantes iberoamericanos de Educación Primaria. Revista de Psicodidáctica/Journal of Pscychodidactics, 18(1), 157-171. Murillo, J y Roman, M. (2010). Retos en la evaluación de la calidad de la educación en América Latina. Revista Iberoamericana de Educación, 53, 97-120 Rivero, J. (2000). Reforma y desigualdad en América Latina. Revista Iberoamericana de Educación, 23 Weurlander, M., Söderberg, M., Scheja, M., Hult, H. y Wernerson, A. (2012). Exploring formative assessment as a tool for learning: students’ experiences of different methods of formative assessment. Assessment and Evaluation in Higher Education, 37(6), 747-460.