"Systematic error/bias, on the other hand, cannot be accounted for with statistics. Returning to the blood pressure example, a sphygmomanometer that is incorrectly calibrated may consistently result in falsely elevated blood pressure measurements. Non-random clustering of variable attributes can flaw our ability to generalise to the general population. So can non-random gathering of the data by the radiology researcher."
Expected headings
"Non-differential and differential bias"
"There are multiple opportunities for bias to creep into a radiology study, some obvious and some subtle. It is the researcher's goal to eliminate any large biases and control or account for any smaller ones 3."