Abstract"Problem" and "pathological" gambling represent core concepts that guide gambling research today. However, divergent interpretation of the relation between these terms is continually misguiding the measurement and interpretation of empirical data, and may cumulatively lead to larger-scale problems of conclusion and policy formulation over the next decade. This paper first attempts to unravel the conceptual muddle by outlining the trajectory of the usage of the two terms, from a period where both were dimensionally similar concepts firmly situated in the addiction model to a more recent conception, which takes the view that problem gambling is distinct and properly measured by focusing on the problems that excessive gambling may cause to individuals, families, and communities. We then aim to analyse and criticize the Canadian Problem Gambling Index (CPGI) as a clear example of the confusion of paradigms, an index that defines problem gambling in the newer, problem-centred model, but continues to measure it with items reflecting the older, addiction-centred model. We argue that results obtained using the CPGI, much like those of its predecessors, will not adequately capture the notion of harm that underpins current definitions of problem gambling.