In the medical field, patients often experience tangible benefits from treatments they expect will improve their condition, even if the treatment has no mechanism of effect. This phenomenon often obscuring scientific evaluation of human treatment is termed the “placebo effect.” Latest research in human-computer interaction has shown that using cutting-edge technologies similarly raises expectations of improvement, culminating in placebo effects that undermine evaluation efforts for user studies. This workshop delves into the role of placebo effects in human-computer interaction for cutting-edge technologies such as artificial intelligence, its influence as a confounding factor in user studies, and identifies methods that researchers can adopt to reduce its impact on study findings. By the end of this workshop, attendees will be equipped to incorporate placebo control measures in their experimental designs.