Using a prediction approach to assess agreement between two continuous measurements.

The problem of assessing agreement between two devices occurs with great frequency in the medical literature. If it can be demonstrated that a new device agrees sufficiently with a device currently in use, then the new device can be approved for general use. This work discusses how a prediction interval can be used to estimate the whether a future difference between two devices will be within acceptable limits with reasonable confidence. The method is illustrated with an example involving measurements of peak expiratory flow.