Backazimuth estimates derived from surface wave polarization can be used to test association of an observed surface wave with a seismic event. However, commonly used techniques for estimating the backazimuth are subject to a number of errors and are often inaccurate. We evaluate the performance of a new algorithm for determining Rayleigh wave propagation direction from the cross-correlation of the horizontal and Hilbert transformed vertical seismograms. This proves to be more accurate and much less error-prone than current automatic processing procedures, and the cross-correlation value provides a good measure of the reliability of the backazimuth estimate. Consequently, the new algorithm will permit more reliable event association at a lower magnitude threshold.