Perceptions that the cohort entering the BE degree is not as well prepared under new national qualifications in engineering pre-requisite subjects such as Calculus and Physics, led to the introduction in 2007 of diagnostic testing in several core courses. The results brought into question the level of student preparedness and reliability of current selection criteria. This paper reports on the preliminary investigation of the relationships and predictive ability of cognitive variables such as aggregated high school qualification scores; individual subject and module scores; and diagnostic test scores with university results. The initial results of this investigation support the existing criteria. It is suggested that a quantitative model using partition tree techniques, might guide the selection process, especially to assist in discrimination of those applicants near the borderlines of admission criteria.