This study describes the web-based self- and peer-assessments system, or the Web-SPA, which has been shown to provide teachers with a flexible interface with which to arrange various self- and peer-assessment procedures. Secondly, this study examines the effects of the application of the progressively focused self- and peer-assessment (PFSPA) procedures that are made available with the Web-SPA. In an evaluative study with 76 third-graders (14 or 15 years old) of junior school, it has been found that the upon completion of the PFSPA activities, the students demonstrate greater objectivity in their self-assessment scores; it has also been shown that significant consistency is found between the students' self- and peer-assessments results and that the assessment results of teachers. Furthermore, the quality of the students' works improved after the assessment activities.