Research progress has been made in recent years in developing service or performance indicators (SPI) or methods to better measure or evaluate service or quality for pedestrians in a local context. The majority of SPIs relate objective (measurable) characteristics or attributes of the right-of-way, with the user’s perceived output variable (e.g., perceived comfort). Traditionally, these methods do not consider the user’s perspective of the input variables. However, there is evidence that the direct contact of pedestrians with the environment justifies an exploration of the contribution of perceptions to that end. This study explores the power of user perception onsite to explain the sidewalk quality of service (QoS), compared to physical and other measurable traditional inputs. Information of physical characteristics, traffic, and perceptions were acquired in 30 different urban rights of way in Bogota, Colombia. By comparing the explanatory power and the goodness of fit of different scenario models, perceptions have been found to be an important predictor to pedestrian perception of QoS. In the light of the results, this paper provides a generalized conceptual framework to explain QoS that complements the existing one and discusses the implication of the use of QoS as the outcome variable.