As computers become more pervasive in opinion-based surveys, research is required to update existing survey methodologies with current computer capabilities and to begin extending current survey methods by validating additional computer-enabled functionality. This need is particularly acute in the measurement of constructs representative of individuals, such as personality, since current methods were not developed for analysis of individuals. This study addresses the current gap in theoretical justification for measurement of individuals, and then contributes to the development of new functionality to account for this gap. First, it uses computer simulation to explore the overall impact of two types of errors introduced by the number of scale anchors. Second, it proposes the functionality of a new data collection tool called the “variable-interval slider (VIS),” a tool that allows the researcher to account for these two types of errors.