What does accuracy matter anyway, so long as a units readout is consistent?
(Andrew Coggan) Accuracy is important if: 1. you wish to compare your performance over the long term with different devices; 2. you wish to compare your performance to others; 3. you want to use a self-assessment tool such as use my Power Profiling tables, or 4. you wish to do any modeling, e.g., to predict your time on a new course. It is true, however, that precision (reproducibility) is probably more important than accuracy but that includes across various power outputs, pedaling speeds, etc., as well as across brands of powermeter. Care must be exercised when comparing data collected using different power meters, even if they have all been carefully calibrated. In my own case, for example, the slight improvement in power Ive seen at various longer durations recently, as compared to previous years, can potentially be accounted for entirely by my switch to SRM from PowerTap, since the former measures power upstream of the chain, whereas the PowerTap measures it downstream, or after t
