This thesis focuses upon the effect of some factors on pupils''/students'' responses in some assessment methods mainly fixed response questions. The research was carried out over three years and the samples were selected from secondary schools both in Scotland and the First Year University of Glasgow students who were taking biology and chemistry courses. The results of the first investigation showed that changing the positions of the key answer and the most plausible distractor (strong distractor) in the multiple choice questions (MCQs) it can have a significant effect in the facility value of the question. The results of the study also showed that changingthe positions of the options within the Structural Communication Grids (SCGs) type of questions also brings, to some extent, a significant difference in the facility value of the questions but not to the some extent as the multiple choice questions. Furthermore, the study investigates the effects of some psychological factors on students'' selections of fixed response questions.