Appendix 2 153
Comparative Table The illustration of the 31 cities diagnostic also includes a comparison of the relative position of a city in relation to the other 30 cities for a subset of the indicators, designed to reflect the areas that constitute current challenges and capacities. The comparative table enables each city to pinpoint its relative strengths and weaknesses compared to other African cities. The target audience is similar to that of the dashboard, but with added emphasis on local policy and management audiences. A subset of indicators from the original set of indicators used to study the 31 cities was selected (see Appendix 4); again, this subset was thought to represent six variables identified as central to IUWM, as well as reliable data that would be accessible to the target audience. The seventh variable on economic and institutional strength was excluded due to the fact that it included most of the national proxies used. Since this was a comparative exercise, city-level data was preferred and national-level data that had been used for the dashboard was deliberately omitted. Methodology A simple methodology based on the one used by the Economist Intelligence Unit4 in their study of African cities was devised. This methodology was chosen for its simplicity and also due to the fact that it limited the level of normalization and aggregation of the indicators by allowing a comparison of the data indicator by indicator. The choice of this methodology also avoided ranking the cities or their comparison against an established benchmark, for it simply compares the values for each indicator for each city between themselves. The data from the selected subset of indicators was then homogenized, and the mean and standard deviation for each of the indicators was calculated (see Table A2.3). The cities and their corresponding individual values for every subindicator have been assigned to one of five intervals depending on how much each of the individual values differed from the mean, plus or minus x times the standard deviation. Each city value has been normalized then aggregated into one single indicator, giving equal weight to each of the subindicators. The values were then classified on a scale of 0 to 4 and matched with the interval they belong to according to their aggregated values. The groups were classified based on different intervals calculated with the mean score and standard deviation as follows: