A technique for trend-adjusting composite indexes used for the measurement of growth cycles. The PAT method is based on constructing a variable trend. Its basis is a 75-month moving average, which means that 37 months of trend are lost at the beginning and, at the end of the period being studied. The lost months are approximated by extrapolation. After estimating the trend, the forecaster next calculates the deviations from the trend, which produces an approximation of the growth cycle. This is used to calculate the phase averages which form the bases for approximating the curvilinear trend. Calculating the deviation of the original observations from this trend is the basis for determining the final growth cycle.