This research studied differential reflectivity (ZDR) in pre- and non-tornadic supercells to determine if a regional bias occurred in the previously found suggested signal in the hook echo region. The previous study focused on the central plains and, with a 95% confidence level, found that the mean ZDR values in pre-tornadic supercells was lower than that of non-tornadic. A new region of study was selected and statistical analysis was performed on pre- and non-tornadic supercells in this new region. The same relationship for ZDR between pre- and non-tornadic supercells was observed in the new region with pre-torndic mean was lower than non-tornadic in the hook echo region. However: due to the small number of cases between both regions and the presence of other regions that tornadic supercells occur, a lack of regional bias in the ZDR relationship can be suggested but not proven. A regional bias in the average ZDR for the cases may have been found but further testing is required. A confirmation of the relationship between ZDR and tornadogenisis also cannot be proven but can be suggested in two regions.