Rater plays an important role in awarding fair judgment to students. However, the difficulty to consider fairness to the student applies, especially for the assessment of competency in practical skill. Therefore, the use of an analytic scoring rubric as a guide can reduce the error due to the nature of rubrics. This present research employs Many Facet Rasch Measurement (MFRM) to explore rater error focusing on severity/leniency effect. Participants comprised of a sample of nine experienced teachers who were employed to assess 68 students in their competency of Electronic Circuit Design process in Vocational College in Malaysia. Students were observed using four-point analytic rating scale. The data were collected and analyzed using FACET, a MFRM computer software program. The results were presented in two ways: at the group level and at the individual level. There is exhibit rater effect at the group level and individual level where the value of chi square is significance, high separation index, high separation ratio and high reliability index.