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Perceived cognitive concerns are common among older adults, with 50–80% of adults over the age of 70 reporting some degree of decline compared to an earlier stage of life (Jessen et al., 2010; van Harten et al., 2018). While objective measures of cognitive functioning (i.e. neuropsychological tests) remain the gold standard for identifying pathological cognitive decline, subjective cognitive complaints (SCCs) are increasingly considered in comprehensive assessments of older adults. Numerous studies have demonstrated that self-reported SCCs are only weakly associated with current objective cognitive ability and are more strongly related to psychiatric factors (Burmester et al., 2016; Crumley et al., 2014). However, emerging research suggests that SCCs may, for some people, represent changes that are not yet detectable on objective testing (Mitchell et al., 2014). Indeed, while many people with SCCs are cognitively healthy (i.e. “worried well”), SCCs in a subset of people may serve as a preclinical marker of neurodegenerative diseases, with implications for early detection and timely intervention (Hessen et al., 2017; Jessen et al., 2014, 2020; Mitchell et al., 2014).Despite increased interest in the clinical utility of SCCs, there are differing opinions on how best to measure and interpret these reports. The study by Truong et al. (2022) expands the existing body of SCC literature by evaluating dynamic and enduring patterns of SCCs reported by patients and informants over a 10-year span. In a large sample of community-dwelling older adults from Australia, the authors used generalizability theory to examine the overall reliability of two widely used measures of selfand informant-reported SCCs – the Memory Complaint Questionnaire (MAC-Q) and the Informant Questionnaire on Cognitive Decline in the Elderly (IQ-CODE). Specifically, they examined how a person (e.g. self vs informant), scale items, occasion, and the interaction of these factors influence the reliability of the two measures when repeatedly measured over 10 years. Outcomemeasures included whether patients met the criteria for dementia diagnosis, decided upon at a consensus meeting with clinicians from varying backgrounds (i.e. neuropsychiatrists, psychogeriatricians, neuropsychologists) using available clinical, neuropsychological, laboratory, and neuroimaging data. In addition, they measured objective cognitive performance using a battery of 10 tests that assessed attention/processing speed, language, executive functions, visuospatial ability, and learning/memory. Truong and colleagues’ results suggest that both the informant-report (IQ-CODE) and a modified version of the self-report measure (MAC-Q) have at least adequate reliability in measuring enduring patterns of SCCs over time, and that the scores were likely to generalize well across time and populations. In reporting on the reliability of these measures, the authors contribute to a growing literature on improving assessment of cognitive impairment in older adults. Prior work has probed the reliability and diagnostic utility of performance-based cognitive tests, to identify those best suited to this purpose (McDonnell et al., 2020; Nielsen and Jørgensen, 2020). Truong and colleagues’ approached the detection of cognitive impairment from the perspective of self and informant-reported cognitive decline, which is a complementary approach to objective testing. In addition to the presented generalizability assessment, Truong and colleagues demonstrated that informant reports significantly predicted future cognitive test scores and dementia incidence across all occasions, while self-reported scores were less accurate in reflecting cognitive abilities and diagnosis at both the first and last assessments. In other words, collateral reports from people who knew the participants well were more consistent in the prediction of participants’ future cognitive decline than were participants’ reports of their own cognitive difficulties. The authors interpreted their findings as evidence that self-reported SCCs may reflect a tendency to ruminate about everydaymemory errors (e.g. walking into a room and forgetting why they entered the room) rather thanmeasuring their actual cognitive capacities (i.e. overall cognitive decline), possibly due to anxiety and stress. In contrast, the reliability and predictive accuracy of informant reports was interpreted as evidence that corroboration from knowledgeable informants is clinically important and useful. To expand upon these findings and further consider the clinical implications of this work, the current Commentary discusses issues International Psychogeriatrics (2022), 34:12, 1007–1010 © International Psychogeriatric Association 2022