2.4. Analytic Strategy
REGRESSION, EVENT, REGRESSIONS
The ACTIVE trial was powered to detect the effect sizes of 0.20 based on the observed effect sizes of previous cognitive training research at the time [Chi-square and ANOVAs were used to test the baseline demographics and Turn 360 differences by baseline fall status. For the Cox regressions, time was right censored and calculated as the number of months between the baseline assessment and the 10-year follow-up for persons who did not report a fall within 10 years. For individuals who either dropped out of the study or experienced a fall, the date of their last assessment or time when a first fall was recorded was used to define the time event, respectively. If participants missed one follow-up session but completed sessions afterward (e.g., a participant missed Annual 1 but completed Annuals 2–10), the date of their last assessment or first reported fall was the time-censored event. Then, base Cox regression models were used to assess the probability that an individual would experience a fall after controlling for baseline Turn 360 and significant demographic covariates using the control group. Then, four sets of models assessing the impact of the cognitive training on future falls were conducted. First, the intention to treat analyses examined the relationship between randomization to training (i.e., memory, reasoning, or speed of processing compared to the no-contact control condition) and time until a future fall. Second, this model was repeated with only participants who received booster training to assess if increased training, via booster, impacted the time until a future fall. Finally, the relationship between randomization to cognitive training and time to a future fall was examined as a function of baseline risk, such that models were examined separately among participants with low (no falls reported prior to baseline) and high (a fall reported prior to baseline) risk of future falls. All data analyses were conducted with SPSS, version 26 (IBM Corporation, Armonk, NY, USA), and significance was considered as 