The five strands of living lab
© 2020 ACM. Since the introduction of the iconic Aware Home project  in 1999, the notion of "living laboratory" has been taken up and developed in HCI research. Many of the underpinning assumptions have evolved over the past two decades in various directions, while the same nomenclature is employed - inevitably in ambiguous ways. This contribution seeks to elicit an organized understanding of what we talk about and when we talk about living lab studies in HCI. This is accomplished through the methods of discourse analysis [66, 69], a combination of coding, hypothesis generation, and inferential statistics on the coded data. Analysing the discursive context within which the term living laboratory (or lab) appears in 152 SIGCHI and TOCHI articles, we extracted five divergent strands with overlapping but distinct conceptual frameworks, labeled as "Visited Places," "Instrumented Places," "Instrumented People," "Lived-in Places," and "Innovation Spaces." In the first part of this article, we describe in detail the method and outcome of our analysis that draws out the five strands. Building on the results of the first part, in the second part of this article, each of the five types of living lab is discussed using some of the prototypical examples of that kind presented in the literature. Finally, we discuss the raison d'être and future position of the living lab as a method within HCI research and design and in relation to advances in sensing technologies and the emerging world of intelligent built environments (e.g., smart city and smart home).