“…In the COTiD study [6], Graff et al (2006) show large effect sizes for all outcome measures, including mood, quality of life, daily functioning, and competence, but these effects were not replicated in successive studies of the same program (Voigt-Radloff et al, 2011a). Next, Gitlin et al (2008Gitlin et al ( , 2010a have demonstrated a decrease in behavioral occurrences of the person with dementia in two studies [4a, 5]; however, the Care of Persons with dementia in their Environments (COPE) study [4b], with comparable intervention components, does not show this effect (Gitlin et al, 2010b). Differences in findings in interventions with comparable treatment components might be explained in several ways.…”