Table 1. Free-Standing Children's Hospital's STS Congenital Heart Surgery Operative and Adjusted Operative Mortality, January 2012 - December 2015. # Deaths / Eligible Cases Observed Mortality Expected Mortality O/E Ratio (95% CI) Adj. Mortality Rate (95% CI) Overall 106 / 2634 4.0% 2.9% 1.39 (1.14, 1.67) 4.0% (3.3, 4.8) STAT Mortality Category 1 3 / 748 0.4% 0.3% 1.23 (0.25, 3.58) 0.5% (0.1, 1.4) STAT Mortality Category 2 15 / 712 2.1% 1.5% 1.45 (0.81, 2.37) 2.3% (1.3, 3.7) STAT Mortality Category 3 14 / 375 3.7% 1.9% 1.92 (1.06, 3.18) 4.5% (2.5, 7.5) STAT Mortality Category 4 42 / 659 6.4% 5.4% 1.18 (0.86, 1.58) 7.6% (5.5, 10.1) STAT Mortality Category 5 32 / 140 22.9% 14.8% 1.55 (1.1, 2.08) 22.4% (15.9, 30.2) 2) If you had to recommend to the Chair where to focus the department's improvement efforts, which STAT mortality category would you suggest and why (limit of 1 paragraph)