The application of maximum entropy spectral analysis to time series measuring economic activity in Canada allows the identification of the time scales of cyclical variations specific to given sectors and to five diverse regions. Aggregate economic activity as measured by the unemployment rate is influenced by a major cycle and seasonal variations. In contrast, monetary activity is solely dominated by a [Formula: see text]-year cycle and can only be an efficient policy device for sectors which fluctuate around the same periodicity on the short term. Such is the case for residential construction which is shown to cohere moderately with interest rates as well as to lag changes in such rates by a significant time span.