## 5 Discussion
Critically, these inquiries capture the extremities of space efficiency and the core area-to-GFA ratio. Within the realm of office skyscrapers, the least efficient space utilization recorded was 63%, while the pinnacle reached 82%. Similarly, the core area-to-GFA ratio oscillated between a minimum of 15% and a maximum of 36%. Analogous fluctuations were observed in residential and mixed-use high-rise developments. Furthermore, a study focused on over fifty mid-rise timber residential units in Finland depicted a space utilization range between approximately 78% and 88%, with an average efficiency of 83% [33]. In our research, drawing upon an analysis of 51 case studies, the average space utilization and core area-to-GFA ratio were calculated at approximately 83% and 10%, respectively. The spectrum of measurements portrayed a wide gamut, with the lowest recorded space efficiency at 70% and the highest at 93%, while the core area-to-GFA ratio ranged from 4% to 21%. This study did not identify notable distinctions in the impact of different core planning strategies on space efficiency, nor were distinct conclusions drawn regarding building forms and structural materials in modern high-rise residential timber structures. Choosing an optimal core type could have potentially mitigated notable ratio variations among these clusters. Likewise, concerning spatial efficiency, implementing custom-tailored building forms and structural materials could have prevented significant disparities among the various groups of buildings. This highlights the importance of thoughtful selection and customization in architectural and structural design to maintain consistency and effectiveness across different building typologies. On the other hand, within the Finnish mid-rise timber apartment cases [33], no discernible scientific link was found between building height and space efficiency. Nevertheless, according to [25; 26; 27], there exists a trend wherein, as the building height escalates, space efficiency tends to decline. This phenomenon is attributed to the expansion of load-bearing components accompanying taller structures. However, noteworthy empirical observations from timber constructions across Europe suggest a potential remedy. Specifically, they indicate that, as the building ascends in height, it becomes feasible to decrease cross-sectional area of load-bearing walls on upper stories [33]. This implies that, despite the conventional notion of decreasing space efficiency with building height, strategic design considerations, especially in timber constructions, can potentially mitigate this effect. Prospective research avenues aimed at advancing the understanding of space efficiency in high-rise timber residential towers could include the following initiatives [99; 100; 101; 102; 103; 104; 105]: 1. Comparative analysis: conduct comparative assessments of space efficiency metrics between high-rise timber structures and conventional materials like concrete and steel. 2. Spatial optimization: utilize computational methodologies to maximize spatial efficiency in timber buildings through the application of optimization algorithms. 3. User-centered design: investigate residents' spatial preferences through surveys and interviews to inform design improvements focused on enhancing usability. 4. Parametric design: employ parametric tools to model and optimize design parameters with the aim of improving space efficiency. 5. Life cycle assessment: perform comprehensive assessments of the environmental impact associated with space-efficient designs in timber constructions. 6. Flexible space design: explore adaptable design strategies to accommodate changing occupancy requirements over time. 7. Smart technology integration: evaluate the potential of Internet of Things (IoT) and automation systems in optimizing spatial utilization within timber structures. 8.