Growing evidence shows that skills other than cognitive are crucial to understand labor market and other outcomes in life. However, little is known about the role of education in improving these abilities for disadvantaged students in developed countries. In this paper we evaluate the effects of a remedial education program for under-performing students from poor socio-economic backgrounds implemented in Spain between 2005 and 2012. We address two questions: (i) Does the program improve skills in test taking beyond cognitive skills? (ii) Can we expect heterogeneous effects depending on the students' gender? Following recent literature, we consider testing and survey behavior, for instance decline in test performance, as measures of non-cognitive skills. We use external evaluations of the schools (PISA 2012) and exploit the variation in the question ordering of the test to compute students' ability to sustain performance throughout it. Our findings suggest that the program had a positive effect on girls' ability to sustain test performance but no impact for boys.