The process of evaluating performance relative to aspirations is widely used by many studies of organizational and technological change. The standard performance feedback model argues that decision makers act in function of attainment discrepancy between performance and aspirations. The theory also states that response to attainment discrepancy is influenced by inertia. Organizational research suggests that there are two types of inertia that we identify in this paper as performance-based inertia, and non-performance-based inertia. We examine the influence of these two types of inertia on the two types of attainment discrepancy as identified by standard performance feedback theory: attainment discrepancy that is based on historical aspirations and attainment discrepancy based on social aspirations. We examine mechanisms that account for the influence of both types of inertia, and derive hypotheses that predict their moderating effect on attainment discrepancy. We test these hypotheses using data on 112 teams that participated in “Robot Wars”, a tournament organized as a contest between teams that field machines specifically designed for the event. Our dependent variable is the magnitude of design change prior to participating in each tournament. Our results show, as predicted, that: performance-based inertia negatively moderates design change in response to attainment discrepancy that is based on social aspirations and; nonperformance-based inertia negatively moderates design change in response to attainment discrepancy that is based on social aspirations. However, contrary to our predictions, our results show no relationship between non-performance-based inertia and design change in response to attainment discrepancy based on historical aspirations. We find a positive and significant result for the relationship between performance-based inertia and design change in response to attainment discrepancy based on historical aspirations. Our study contributes to research on the relationship between performance feedback and technological decision making in contexts where inertia can alter assessment of new product introduction risks.