Training is required for humans to develop or further their skills. Many vital skills necessitate strict learning protocols and may be expensive and time consuming. So, any advancement in technology or science which might reduce the cost, either financial or temporal, will be of use to many people. For this reason, simulated training has gained acceptance as a means to increase training efficiency. Such training would include any technology utilizing mixed reality (MR), including both augmented reality (AR) and virtual reality (VR). These technologies can reduce some of the costs associated with training and can eliminate many risks by placing individuals in a simulation rather than in real-world dangerous situations. However, training in MR does not solve all the problems that plague current training methods. While simulation may be the solution to many issues, it comes with its own set of caveats. One must consider whether mixed reality is in fact an effective medium for training. The most obvious complaint is the applicability of the training to execution of the task in the real world. The principle of encoding specificity indicates that when the learning environment is sufficiently different from the environment where that learning is measured, performance tends to suffer (Tulving & Thomson, 1973). This principle was further explored by Godden and Baddeley (1975) who found that scuba divers who memorized lists of words on dry land recalled those lists better above-rather than below-the surface of the ocean. This parallels many training situations and calls into question whether learning properly transfers between scenarios. One can extend the same caution to training in MR. The situations in which simulation-based training has the most benefit (risky, expensive, or unsafe conditions) also have the highest cost of failure. For these reasons, it is imperative that transfer of training from virtual reality be measured to determine whether the transfer is effective overall. A meta-analysis of the current empirical literature on the subject is a good way to begin to understand the effect of virtual training on performance.