The different variables used in the construction of the two sub-indexes leads to a great difference in scores assigned under them. The physical sub-index favours coastal regions that are low in elevation relative to the mean sea level and underlain by sedimentary rocks that have a low resistance to the erosive strength of waves, assigning these areas high index values. The socio-economic index favours large population centres with a high incidence of infrastructure and urban land use, evaluating large cities like Victoria and Nanaimo as the most at-risk. The importance that either sub-index places on the determining factors of sensitivity to sea level rise naturally leads to a great disparity in patterns of index scores produced, as seen in the map below. Index differences were calculated as:

Index Difference = Physical Sub-Index Scores – Socio-Economic Sub-Index Scores

Areas that were assigned higher physical than socio-economic index scores have positive difference values, and denoted in dark blue. Areas that have greater socio-economic index values than physical index values are negative, and denoted in orange.

Regions near large cities (Victoria, Nanaimo) and low-lying smaller settlements with underlying sedimentary bedrock (Duncan) saw the greatest difference in sub-index values. The designation of certain coastal areas as provincial/national parks or conservation areas is likely to be the factor behind the higher socio-economic sub-index values along the west coast of Vancouver Island.