This study will use the unique features of the Connecticut Tumor Registry to evaluate time trends of cancer incidence in Connecticut over 45 years of population-based cancer registration. The study will first refine and computerize as far as possible the method of time trend analysis and then apply this method to the 60 anatomic sites designated in the recently published Forty Years of Cancer Incidence in Connecticut. The ultimate purposes of the undertaking are to (1) refine and systematize a comprehensive method of time trend analysis so that other epidemiologists may readily apply this technique to population-based cancer registries; (2) supplement the evaluation of ascertainment and classification in population-based cancer registration; (3) generate hypotheses of cancer etiology; (4) monitor trends in cancer risks in the population for preventive purposes. The study will emphasize comparisons of cohort and period models of time trends, statistical testing for goodness of fit of modeled data, identification of strongest correlates of the rate, and programming for optimal inspection of trends. A publication focusing on statistical and computer methodology will be produced midway in the study.