Deakin CD, et al. - Researchers sought to assess if healthcare professionals could accurately judge their delivered compression depth by 0.5 cm increments. In the current work, rescuers were able to judge 0.5 cm differences in compression depth with accuracy. However, they remained unable to accurately judge overall target depth. A reduction in the current recommended compression depth to 4.56 cm could result in delivered compressions significantly below the optimal depth.