This study examines the influence of demographic factors such as age, sex, and school setting on self-estimate ability. The subjects (N = 1814) in this study were administered an interest inventory (Vocational lnterest Survey) and a self-rating scale (Work Interest Survey). Similarity between self-estimate and measured interest profiles was assessed using the correlation between individual's profiles and the squared Euclidean distance (D2), and its components (elevation, scatter, and shape by scatter). There were significant differences between boys and girls on profile parameters of elevation, the overall distance between profiles, and self-estimate ability. Girls, on the whole, were better able to estimate the pattern of measured interests (0.62), compared to boys (0.55), but the magnitude of this difference between these coefficients (i.e., 0.07) was very small. Age differences between four age groups (14, 15, 16, and those over 16 years) were small. The mean correlation at 14 years was 0.64 compared with 0.57 at 16 years and 0.4 for those over 16 years. Differences between single-sex schools and co-educational schools were the third factor considered. Girls' schools had the highest correlation between the VIS and WIS profiles (0.63), followed by co-educational schools (0.58) and boys' schools had the lowest profile correlation (0.55).