Three Bland–Altmann plots comparing the experts and the cardiologists, the experts and the novices, and the cardiologists and the novices, respectively. Blue line marks a 0 mm difference. Red full line illustrates bias where novices systematically underestimated the length compared with experts and cardiologists. Red dotted line marks ±2 SD (95% LOA). Graph A compares experts and cardiologists. Cardiologists measured a mean of 0.1 mm larger than the Experts indicating no overall measurement difference between the groups. The 95% LOA was −3.2 to 3.0. Graph B compare experts and novices. The experts measured a mean of 0.7 mm larger than the novices. The 95% LOA was −3.6 to 4.9. The last graph compared the cardiologists and the novices. The cardiologists measured 0.8 mm larger than the novices with a 95% LOA of −4.6 to 6.1. There is no systematical bias in either of the graphs.