Since the emergence of Life Cycle Assessment (LCA), many studies have focused on the integration of uncertainties. Nevertheless, Data Quality Assessment (DQA) and statistical approaches are not yet widely used to quantify uncertainty, and when used, methodologies are neither uniform nor rigorous. Moreover, the data required to propagate and estimate the overall uncertainty are often lacking. Finally, the quantification of uncertainty could introduce more confusion in decision-making. In this context, we propose joint implementation of both the qualitative and quantitative approaches to estimate uncertainties when performing Life Cycle Assessment of complex systems. Using an existing LCA on grocery bags, this study first attempts to demonstrate the usefulness of both the qualitative and quantitative approaches to deal with uncertainty. Secondly, given that data collection is very time-consuming, the usefulness of both the qualitative and quantitative approaches will be discussed.