Several changes to entry and selection to medical school in Ireland were introduced in 2009 including the addition of a specialised admission test the Health Professionals Admissions Test (HPAT-Ireland).We wished to determine the impact of each aspect of the reforms by modelling outcomes if old and new mechanism had prevailed, the extent to which applicants and entrants repeated the leaving certificate, and leaving certificate and HPAT-Ireland scores of successful candidates.The leaving certificate and HPAT scores of all medical school applicants and entrants in 2009 and 2010 were analysed.Data were available for 2,913 applicants in 2009 and 3,292 applicants in 2010. In 2009, over 33 % of students admitted to medicine would not have been admitted if the decision was based solely on their leaving certificate. The corresponding figure for 2010 was 44 %. In 2009, if entry had been based on the combined HPAT-Ireland and an un-moderated leaving certificate score, this would have affected the outcomes in 5 % of applicants or 25 % of those who secured a medical school place. The corresponding figures for 2010 are 6 and 24 %, respectively. Since 2009 applicants and entrants are far less likely to repeat the leaving certificate examination. HPAT-Ireland entry scores appear relatively stable while leaving certificate scores have varied in an upward direction.All of the reforms to medical school admission have contributed significantly in determining outcomes. The addition of the HPAT-Ireland adjunct admission test equates with the impact of moderation of leaving certificate points.