When a model's output (value plus error bounds) already falls within the error bounds of the observations, it is a Bad Idea to try to tune a model through purely arbitrary adjustment of parameters. (skepticalscience.com)
This comes in addition to the previously shown fact that the correlation of cosmic ray flux with paleoclimatic data proposed by Shaviv and Veizer (2003) only arises «by making several arbitrary adjustments to the cosmic ray data» (Rahmstorf et al. 2004). (realclimate.org)
And for his calculation, which worked before WWII, he started adding the 50 % arbitrary adjustment starting in the early»60s as I have mentioned before. (greenbackd.com)