Embodiments relate to systems and methods for analyzing data extracted from a set of data sources. A set of applications such as online analytical processing (OLAP) applications can access the combined data of a set of data sources via an aggregation engine. The set of data sources can be configured with diverse dimensions and associated data. In general the data sources may not be expected to reflect a strictly consistent structure. In embodiments, the aggregation engine can combine or aggregate the set of data sources using common dimensions or data points, and build an index into a transform table reflecting a combined mapping. An OLAP or other application can then perform statistical computations, searches, sorts, and/or other operations on the combined mapping, even when the original data sources do not contain identical dimensions or other formats.