Fig. 1

Bias plots (upper, A: SBP, B: DBP) and Precision plots (lower; C: SBP, D: DBP) comparing simultaneous BP measurements performed by oscillometric wrist and upper-arm monitors on opposing arms. The x-axis displays the “BLUP of x”, where BLUP stands for Best Linear Unbiased Prediction: an estimate of the true BP of the study participants given the two noisy measured values by the oscillometric devices. Both Bias plots show that the higher the true BP the larger the bias (shown by the red dash-dotted line measuring the vertical distance between the two regression lines (black for the upper-arm and grey for the wrist devices) whose distance can be read on the right y-axis). Likewise, the two Precision plots show that the standard deviation of measurement errors was larger for the wrist device. SBP systolic blood pressure, DBP diastolic blood pressure