Objective: The current study seeks to examine the extent to which older adults (>65 years) were administered the Wechsler Memory Scale Logical Memory Delayed subtest (LMII) within the standard 35 minute delay, including the degree to which the delay duration affected proportion of information retained across the delay. Method: The WMS Logical Memory Immediate (LMI) and LMII subtests were administered to 43,201 participants in the National Alzheimer's Coordinating Center's Uniform Data Set (UDS; Weintraub et al., 2009); only participants with probable Alzheimer's disease (AD; N = 14,476), probable vascular dementia (VaD; N = 593), and cognitively normal controls (N = 28,132) were included in this study. Using a general linear model, we analyzed the effect of delay duration on proportion retained (PR) on LMII across groups, then confirmed our findings by controlling for LMI performance. Results: Only 49.7% (N = 21,483) of participants were administered delay durations within the standardized range. The effect of delay duration on PR differed significantly across groups (F(84, 43,057) = 6.25, p < .001). Delay duration was negatively associated with PR among VaD patients but it did not influence PR for other groups. This delay duration by group interaction remained after controlling for LMI performance (F(84, 43,056) = 6.18, p < .001). Conclusion: Findings indicate that delay duration has an effect on recall performance for some patients. Given that clinical goal is usually to clarify diagnoses and memory performance informs clinical decisions, the possibility that deviations from standardized delays can lead to wrong clinical decisions exists. These findings highlight the importance of adhering to standardized administration guidelines.