Percentage of acceptable images per resident by study group. Left: percentage of acceptable images per exam obtained by all study participants (n = 42); mean 48% in control group versus 71% in simulator group; P = 0.021. Right: percentage of acceptable images per exam obtained by residents with no previous transesophageal echocardiography (TEE) experience (n = 24); mean 30% in control group versus 62% in simulator group; P = 0.038. Boxplots indicate minimum, maximum, median, lower, and upper quartiles. Crosses (+) indicate the mean for each group.