Mid-air interaction involves touchless manipulations of digital content or remote devices, based on sensor tracking of body movements and gestures. There are no established, universal gesture vocabularies for mid-air interactions with digital content or remote devices based on sensor tracking of body movements and gestures. On the contrary, it is widely acknowledged that the identification of appropriate gestures depends on the context of use, thus the identification of mid-air gestures is an important design decision. The method of gesture elicitation is increasingly applied by designers to help them identify appropriate gesture sets for mid-air applications. This paper presents a review of elicitation studies in mid-air interaction based on a selected set of 47 papers published within 2011-2018. It reports on: (1) the application domains of mid-air interactions examined; (2) the level of technological maturity of systems at hand; (3) the gesture elicitation procedure and its variations; (4) the appropriateness criteria for a gesture; (5) participants number and profile; (6) user evaluation methods (of the gesture vocabulary); (7) data analysis and related metrics. This paper confirms that the elicitation method has been applied extensively but with variability and some ambiguity and discusses under-explored research questions and potential improvements of related research.Multimodal Technologies and Interact. 2018, 2, 65 2 of 21 such thing as a universal gesture vocabulary for every application" [15]. Thus, the identification of appropriate gestures for mid-air user interactions in terms of criteria like discoverability, memorability, performance, reliability and comfort, is an important design decision. This must be made at the early stages of system development and it severely affects the development course of every mid-air application project as well as the user experience (UX) of intended users.Emerging from the field of participatory design, gesture elicitation studies have been widely applied to help designers select the most appropriate gesture set for a given application. Although the method does not have a strict procedure, the main approach is to first define what operations (called "referents") have to be executed through gestures, then ask the end users to propose at least one gesture that they find preferable for each referent and finally to extract the gesture vocabulary after analysing the collected data [16]. The goal of a gesture elicitation study is to extract "good" gestures, which according to Morris et al. [17] are "gestures that meet certain design criteria such as discoverability, ease-of-performance, memorability, or reliability."Over the last few years, several elicitation studies have been conducted to identify mid-air gesture vocabularies for many different application domains and contexts, devices, types of digital content and tracking technologies subsumed. A survey of elicitation studies of mid-air interaction is useful to HCI researchers and interaction designers for deepening th...