# New Approaches in Dynamic Metrics for Lighting Control Systems: A Critical Review
## 5 Discussion of Results
### sDA, ASE, and DA\({}_{\text{avg}}\)  
The results for sDA and DA\({}_{\text{avg}}\) tend to be comparable--or nearly identical--in several London models, particularly during the 08:00 to 18:00 timeframe. In Seville with a 500 lx threshold, the gap between them begins to widen, although in Seville with a 300 lx threshold, the similarity remains notable. Despite the absence of a perfect correlation between sDA and DA\({}_{\text{300}}\)--some models like SEV40_300 (Figure 5) exhibit differences of up to 26%--both metrics appear to provide similar information in many cases. As expected, DA\({}_{\text{500}}\) presents significantly greater discrepancies, reaching up to 46% in the case of SEV40_500. However, the relationships among lighting metrics are not consistent across all geographic locations and orientations. An example of this variability is observed in London with a north-facing orientation (Figures 6-8), where DA\({}_{\text{avg}}\) tends to slightly exceed sDA. In contrast, for most other analyzed orientations and locations, sDA typically shows higher values than DA\({}_{\text{avg}}\). This variability underscores that the interpretation of the relative performance between DA\({}_{\text{avg}}\) and sDA is highly context-dependent, shaped by both geographic location and room orientation. In south-facing orientations, ASE also shows a close correlation with the other two spatial metrics, given the direct solar exposure characteristic of unshaded south-facing apertures. Nevertheless, the commonly used ASE threshold of 10% as an upper limit appears questionable. Firstly, in almost all models, achieving sDA values recommended by IES LM-83-12 [52]--between 50% and 75%--also entails exceeding this 10% ASE threshold. Additionally, in the London models with a northward orientation (Figures 6-8), ASE consistently exceeds 10%, yet according to UDI, the results are not especially concerning in terms of excessive illuminance across the room, except for those points closest to the window. As was mentioned in the introduction, spatial metrics lack the granularity inherent to other metrics. UDI, by contrast, reveals that high illuminance values above 2000 lx are typically concentrated mostly in the first two or three points near the window. Beyond this zone, values within an \"acceptable\" UDI range become predominant, while the rear areas of the space more often fall below minimum thresholds. An exception is found in Seville with a south-facing orientation, where acceptable illuminance levels are maintained even at the very back of the room. This lack of spatial precision can be observed in the comparative analysis of SEV30S_300_0814 (Figure 4) and LON40S_300_0814 (Figure 8). Although both models display nearly identical sDA (100% and 100%) and ASE (64% and 66%, respectively) values, the UDI results differ markedly: in the London case, the rear half of the room falls below the minimum UDI threshold between 30% and 44% of the time, whereas in Seville, most of the space remains within acceptable daylight levels. This suggests that while spatial metrics like sDA and ASE can provide a useful indicative assessment, they may obscure important spatial variations in lighting quality that are better captured by more granular metrics such as UDI. While simulation-based analysis provides valuable insights, future research involving empirical validation in real buildings will be essential to confirm the predictive reliability of these metrics under actual use conditions. The key aspects to highlight from this section are as follows:  
* sDA and DAavg show similar or nearly identical results in several London models during the 08:00-18:00 period. In Seville, with a 300 lx threshold, they remain closely aligned in various models; however, there are discrepancies of up to 26%. * In London with a north-facing orientation, DAavg slightly exceeds sDA, though in most other cases, sDA exceeds DAavg. * ASE shows a stronger correlation with sDA and DAavg in many of the south-facing models due to increased direct solar exposure.