Figure 3From: Effects of zero reference position on bladder pressure measurements: an observational study Bland and Altman analysis. According to Bland and Altman analysis, the calculated bias was 2.01; precision at 1.49; two SD of 2, 98; limits of agreements -0.91 to 4.93; and error of 35.1%. This percentage of error is too high (percentage of error recommended is 25%). IAP, intra-abdominal pressure; MAL, midaxillary line; SP, symphysis pubis.Back to article page