The time it takes to process a visual stimulus is of importance in many areas of experimental psychology and beyond. One popular measure of stimulus-processing speed is derived from a manipulation of the number of stimuli (set size) in a visual-search task. This measure is the slope of the linear function relating the time needed to find a single target stimulus to set size (search slope). Compared to other approaches for measuring stimulus-processing speed, this has the advantage of isolating stimulus processing and relegating all extraneous processes (e.g., related to response selection) to the intercept of the linear function. Unfortunately, this “traditional” search slope is confounded in multiple ways and, consequently, is not actually suited to quantify stimulus-processing speed. Consequently, we have developed an alternative approach to measuring search slopes. Our new Systematic-Search paradigm reliably induces a specific search order, so that search slopes can be derived from the effect of target position rather than set size. We have validated this approach by showing that the position slope is affected by visual complexity, but not by the difficulty of response selection.