The purpose of this study was to invesigate whether there are general tendencies to overestimatem underestimate, or estimate accurately their academic achievement across subject areas, and if so, whether the self evaluation types will affect on the score of KRIVET Vocational Aptitude Inventory, which is adopting self assessment method. Results show that there are general tendencies to overestimate, underestimate, or estimate accurately across academic subject areas, but these tendencies were not directly transferred to KRIVET Vocational Aptitude Inventory scores. This result was interpreted as the evidence for supporting the validity of self-assessment method of the KRIVET Vocational Aptitude Inventory.