Programming style guidelines and automated coding style analyzers have been developed without a solid experimental or theoretical basis. In this paper we make a distinction between typographic style characteristics and underlying structural style content and show that this distinction aids in assessing the influence of style factors. This distinction permits straightforward identification of specific style factors and a better understanding of their effect on program comprehension. The results of our studies have a direct impact on automated coding style assessment programs, programming standards, program maintainability, and code formatting tools.