In this paper, we develop a summary statistic that tracks periods of business cycles in selected Asian economies at monthly frequency. We apply principal component analysis (PCA) to indicators from individual economies to construct an Economic Activity Index (EAI). The index is projected onto GDP at both business cycles and growth frequency to provide an indication of real-time performance of an economy. The index also retains granularity, linking the aggregate index with individual macroeconomic series. We demonstrate how more rigorous information selection techniques can improve upon the accuracy of tracking business cycles and GDP growth.