The Alzheimer’s Disease Knowledge Scale, commonly abbreviated as ADKS, contains thirty true-or-false items that span the full landscape of the disease: risk factors, symptoms, diagnosis, course of illness, treatment and management, prevention, caregiving, and life impact. Because the scale has been validated in numerous languages and settings, it serves as a benchmark for comparing knowledge levels across cultures and professional groups. But a scale is only as useful as the fidelity of its translation. A poorly adapted version can introduce linguistic ambiguity, cultural mismatch, or items that simply do not function as intended, which would make any conclusions about knowledge levels unreliable. The research team therefore adopted a structured, multi-stage cross-cultural adaptation protocol before administering the instrument to a single participant.

That protocol began with forward and backward translation. Bilingual translators independently rendered the original English items into Persian, and a separate team then translated the Persian version back into English. By comparing the back-translation with the original, the researchers could detect subtle distortions in meaning, idiomatic phrasing that did not transfer, or terms that carried different connotations in Persian. Next came expert review. A panel of specialists in dementia, geriatric medicine, psychiatry, and psychometrics evaluated each item for clarity, relevance, and cultural appropriateness. They quantified their agreement using the Content Validity Ratio, or CVR, a statistic that reflects the proportion of experts endorsing an item as essential or appropriate. Every one of the thirty items met the critical CVR threshold established by Lawshe’s method for panels of the size used, meaning that the expert consensus supported the content relevance of the entire scale. Finally, a pilot test with a small group of target respondents allowed the team to check comprehensibility and flag any remaining ambiguities before the main data collection.

The main study was conducted as a cross-sectional survey involving 304 healthcare professionals and students in Iran. Participants completed the Persian version, now designated the ADKS-P, and the researchers analyzed the results with a battery of classical psychometric techniques. The mean total score on the ADKS-P was 20.27 out of a possible range of 0 to 30, with a standard deviation of 3.62. This corresponds to roughly 68 percent correct answers, a figure suggesting a moderate but hardly comprehensive command of Alzheimer’s disease facts among the very people who will be diagnosing, treating, and counseling patients with the condition. The finding echoes a consistent pattern in the international literature: healthcare trainees and practitioners often hold fragmented knowledge about dementia, particularly regarding risk factors, prevention, and caregiving, even when their clinical familiarity with affected patients is substantial.

Reliability was assessed in two complementary ways. Internal consistency, which measures how coherently the items perform as a set, was estimated with Kuder–Richardson Formula 20, or KR-20, the appropriate statistic for dichotomously scored true-or-false items. The KR-20 value came out at 0.64, a modest figure that falls below the 0.70 benchmark conventionally regarded as acceptable for research instruments. The researchers interpret this as a reflection of the scale’s conceptual breadth: because the thirty items deliberately sample knowledge across eight distinct domains, respondents may know a great deal about one domain and little about another, which suppresses inter-item correlation. The original English ADKS has shown similarly moderate internal consistency in previous studies, so the Persian result is not anomalous. Test–retest reliability was examined by readministering the scale to a subset of participants after a two-week interval, and the correlation between the two administrations was moderate at r = 0.53 with a p-value of 0.016, indicating statistically significant temporal stability, though again at a level that leaves room for improvement.

Item-level analysis revealed additional challenges that the authors were careful to document. Fifteen of the thirty items showed weak discrimination, with item–total correlations below 0.20, meaning that performance on those items did not track well with overall knowledge as captured by the rest of the scale. One item, item 24, actually showed a slightly negative correlation with the total score, at r = −0.05. Weak item discrimination can arise for several reasons, including items that are so commonly answered correctly that they fail to distinguish among respondents, translation-induced ambiguity, or content that is factually debatable or culturally loaded. The researchers argue that these findings argue for careful revision of particular items and further psychometric refinement, rather than abandonment of the scale, especially since the aggregate performance of the instrument on other indices remained serviceable for certain research purposes.

Validity was examined from several angles. Beyond the content validity established through the expert panel, the team tested what psychometricians call known-groups validity: the expectation that the scale should yield different scores for groups that differ theoretically in their level of Alzheimer’s knowledge. Three grouping variables were used. First, education: participants with higher educational attainment scored higher on the ADKS-P, which is exactly the pattern one would predict if the scale is sensitive to genuine differences in knowledge. Second, occupation and professional role: healthcare professionals outperformed students, again consistent with the notion that clinical experience accumulates disease-specific knowledge. Third, familiarity with dementia: participants who reported greater personal or professional familiarity with people living with dementia scored higher than those without such contact. The convergence of all three comparisons in the predicted direction provides preliminary evidence that the Persian scale behaves as a knowledge measure should, distinguishing among respondents in meaningful ways. Statistical analyses, conducted with the Statistical Package for the Social Sciences, included analysis of variance for group comparisons, and the team also considered intraclass correlation coefficients in the context of the reliability assessment.

Why does a validated Persian-language measure of Alzheimer’s knowledge matter? Iran, like many middle-income countries, is experiencing a rapid demographic transition, with a growing elderly population and a corresponding rise in dementia prevalence. Early diagnosis, effective management, and compassionate caregiving all depend on frontline healthcare workers possessing accurate knowledge about the disease. Yet until now, there has been no properly adapted instrument to benchmark that knowledge in Persian-speaking settings. Without such a tool, educational programs aimed at closing knowledge gaps cannot be designed systematically, their impact cannot be measured, and knowledge levels cannot be compared across hospitals, universities, or regions. The ADKS-P fills that gap at the group level. The authors are explicit that it is best suited for baseline assessments of knowledge in groups—comparing a nursing cohort before and after a training program, for example—rather than for high-stakes evaluation of individuals, and they recommend further refinement and validation before broader application.

The study also carries lessons for the science of cross-cultural adaptation more broadly. The findings illustrate that a translation can pass expert content validation with flying colors—every item met the CVR threshold—and still exhibit imperfect statistical behavior in the field. Expert judgment and empirical item analysis are complementary, not interchangeable, and both are necessary. The modest KR-20 and the weak item–total correlations identified in this study give future researchers a concrete roadmap: which items to examine, which domains may need rewording, and which aspects of the scale require larger and more diverse samples to evaluate thoroughly. The authors also suggest that future work could employ modern psychometric methods, such as item response theory, to analyze item functioning in finer detail than classical indices allow.

Ethical oversight was integral to the research. The study received approval from the ethics committee of Tehran University of Medical Sciences under registration number IR.TUMS.MEDICINE.REC.1401.202, and all procedures were conducted in accordance with the Declaration of Helsinki. Written informed consent was obtained from all participants, who were assured of the confidentiality and anonymity of their responses. The authors declare no competing interests and received no external financial support for the research or its publication. The article is published open access under a Creative Commons license, making the psychometric evidence and the adaptation process transparent and available to researchers throughout the Persian-speaking world and beyond.

As Alzheimer’s disease continues its global expansion, the tools used to prepare the healthcare workforce for that challenge must expand with it. This study delivers the first carefully documented Persian adaptation of the Alzheimer’s Disease Knowledge Scale, backed by a transparent methodological trail and an honest appraisal of its strengths and shortcomings. With a mean score of 20.27 among 304 Iranian healthcare professionals and students, evidence that scores rise with education, professional role, and dementia familiarity, and clear documentation of the items that need refinement, the ADKS-P now provides Persian-speaking researchers and educators with a defensible starting point. The message from Tehran, Sydney, St. Louis, and Hatfield is ultimately an optimistic one: measuring what healthcare workers know about Alzheimer’s disease is the essential first step toward teaching them what they do not yet know, and that first step has now been taken for the world’s hundreds of millions of Persian speakers.