Health planners and epidemiologists have begun to use spatial analysis and Geographic Information Systems (GIS) to explore socioeconomic inequalities that can affect population health. In particular, the use of area-based composite indices, also known as deprivation indices, has been effective at incorporating multiple indicators into an analysis. We used GIS-based Multicriteria Decision Analysis (MCDA) to create a weighted index of health service need, and explored the standardization step in MCDA within a geovisualization environment. In a neighbourhood prioritization scenario for the City of Toronto, we implemented an MCDA using two common standardization techniques and three methods for standardizing cost criteria. We compared the resulting scores and rankings of neighbourhoods, and show that standardization is an important consideration in the data analysis process. We conclude with an assessment of the appropriateness of using one technique over the other as well as the potential effect on decision-making related to health policy.