The adjusted responses are the raw responses divided by the ratio of the assay tracer/mean tracer of the reference assays. The adjusted responses factor out the tracer label variation between assays. The reaction, analyte, and random variation between assays are not factored out in the adjusted responses. The tracer label, such as labeled cells in a bioassay, can cause significant variation between assays. Including a tracer sample of just the labeled material can significantly reduce the variance in the weighted regressions. It also causes the adjusted responses to start at the same magnitude each assay.