## 1 Introduction
[PERSON] and [PERSON] [47] explored spatial effectiveness in high-rise offices, highlighting the influence of structural systems and core configuration. [PERSON] et al. [48] studied the interplay between spatial optimization and the comprehensive expenditure of towering office edifices. Their findings unveiled a significant influence of enhanced spatial efficiency on attaining the targeted benchmarks of indoor environmental comfort. [PERSON] and [PERSON] [49] assessed spatial efficiency ratios in mixed-use high-rise structures, highlighting the integration of optimal structural systems and forms to enhance spatial effectiveness. As evident from the literature review conducted earlier, the current scholarly literature lacks sufficient exploration of spatial efficiency within the domain of high-rise timber residential developments, which constitute a notable subclass of tall wooden structures. To fill this significant knowledge gap and gain a deeper understanding of global trends, this article aims to systematically map, aggregate, and analyze data pertaining to spatial efficiency in high-rise timber residential buildings. Through an extensive examination of 51 cases worldwide, the study scrutinizes critical architectural and structural attributes, seeking to elucidate patterns and insights in this underexplored domain. To fathom spatial optimization alongside pertinent parameters for the blueprinting and erection of these complexes, the research inquiries are delineated as follows: (1) What delineates the spatial effectiveness within the sampled group of buildings, and what spectrum encapsulates these proportions? (2) What ramifications do architectural and structural planning factors impart on the spatial efficiency of these cases? (3) What actionable recommendations may be proffered to enhance spatial efficiency? The main goal of this study is to carry out a rigorous and systematic examination aimed at advancing the comprehension of spatial efficiency within high-rise timber residential towers. Through a comprehensive analysis of data extracted from 51 case studies, the study seeks to elucidate critical design variables impacting spatial optimization in these structures. By scrutinizing core arrangements, building forms, structural material and system selections, and spatial efficiency indicators, the research endeavors to offer empirically driven insights and develop methodological frameworks tailored to inform the practices of architectural designers and relevant stakeholders engaged in the development of high-rise timber residential structures. Concerning the description of tall or high-rise structures, a universally accepted criterion regarding their elevation and story count is yet to be established, and even the categorization of 'tall' or 'high-rise' in the realm of wood constructions remains a subject of continuing discourse. In this exposition, a 'high-rise timber building' is explicitly characterized as an edifice comprising eight stories or more [50]. It is worth noting that the hygroscopicity of wood, referring to its ability to absorb and release moisture from the surrounding environment, plays a crucial role in the space efficiency of timber-framed buildings [51; 52; 53]. Wood has a natural tendency to swell and shrink in response to changes in humidity levels, which can affect the dimensional stability of structural elements and finishes within a building. When exposed to high humidity, wood absorbs moisture, causing it to swell, potentially leading to warping, buckling, or distortion of building components. Conversely, in dry conditions, wood releases moisture and may shrink, leading to gaps or cracks. Understanding and managing the hygroscopic behavior of wood is essential for ensuring the long-term performance and durability of wooden structures, as well as optimizing space efficiency by minimizing the impact of dimensional changes on building integrity and esthetics.