Does secular polar motion exist

A statistical test is applied to the null hypothesis according to which the rates of linear trends in observed latitude variations are independent random quantities, to decide whether the variations in mean latitutde are induced by secular polar motion. It is found that, since the measurements at the Mizusawa, Carloforte, Gaithersburg and Ukiah International Latitude Service stations during 1899-1978, as well as at the Kitab station during 1931-1978, do not contravene the null hypothesis, the existence of secular polar motion cannot be demonstrated.