This study measured the technical efficiency, pure technical efficiency, and scale efficiency of 47 retail stores using data from Z Distribution through the nonparametric DEA (Data Envelopment Analysis) approach. The measurement methods for inputs used in existing DEA studies on retail stores, along with an excessive number of inputs, not only create difficulties in decision-making but also make it impossible to identify inefficient retail stores when the number of stores is small. Therefore, this study modified and supplemented the shortcomings of prior research. The findings confirmed that scale inefficiency, rather than pure technical inefficiency, is the primary source of inefficiency, and that nearly all DMUs exhibit increasing returns to scale. This phenomenon suggests that for inefficient DMUs to become efficient, rather than adopting a strategy of maintaining existing outputs by reducing inputs, it is preferable to increase outputs by augmenting inputs through measures such as retraining existing employees or introducing new technologies. However, if such a strategy is not feasible, efforts should be made to increase outputs while maintaining existing inputs as much as possible.