This study was followed by "Regional Model Life Tables and Stable Populations" (1966), which he co-wrote with Paul Demeny. These model life tables both established new empirical regularities and proved invaluable in the development of later techniques for estimating mortality and fertility in populations with inaccurate or incomplete data. Along with William Brass, Coale pioneered the development and use of these techniques, first explained in "Methods of Estimating Basic Demographic Measures From Incomplete Data" (1967, with Demeny) and in "The Demography of Tropical Africa" (1968, with other demographers).