Scarce data and large uncertainties
The data available to establish the dose-effect relationships are rare and comes with substantial error margins. The main data sets currently available, are taken from the irradiated survivors of Hiroshima and Nagasaki. The error bars associated to a data point means that the real risk value has a 70% likelihood of falling somewhere between the edges of the bar. At small dose values the uncertainties are so large that it is impossible to explicitly discriminate between the three proposed models drawn on the plot.