Finally, Table 12 shows the outcomes of studies with age confounds favoring older adults (ongoing task confounds, intelligence confounds, or both).
Thus, each age contrast was classified into one of the two categories: age contrasts with no confounds and age contrasts with confounds favoring older adults (e.g., ongoing task confounds favoring older adults, intelligence confounds favoring older adults).
Confounds favoring old are primarily of the two kinds: ongoing task confounds and participants' intelligence confounds.
Perhaps not surprisingly, claims of no age-related declines in ProM with focal cues are similarly based on data compromised by ceiling effects, intelligence age-confounds, ongoing task-age confounds, low statistical power, and studies of vigilance.
The designs with ongoing task confounds can answer only one question: what are age differences in prospective memory when these confounds are present, that is, when the ongoing task is made easier for older versus younger adults?
Ongoing task confounds favoring older adults were introduced by Einstein and McDaniel [11] who made the ongoing task easier for older adults relative to younger adults; this design was subsequently adopted by a number of other investigators (e.g., [12], [35] [38]).
Ongoing task confounds favoring older adults were originally introduced by Einstein and McDaniel [4] who made the ongoing task easier for older than for younger adults and these confounded designs were later adopted by a number of investigators who followed in their steps.
One might argue that Einstein and McDaniel [4] and others who incorporated the ease of ongoing task confound into their designs aimed to equate functional difficulty of ongoing tasks for younger and older adults and that age declines under these "functionally equated" conditions reflect true age differences in prospective memory.
Thus, the lack of statistically significant age differences in Einstein and McDaniel's [4] study can be interpreted only in light of this ease of ongoing task confound that did not succeed in equating performance on the ongoing task but made it easier for older versus younger adults.
Similarly, Kliegel et al. 's [25] meta-analysis suffered from a number of shortcomings including the omission of many published studies, and failure to consider methodological artifacts such as ceiling effects, intelligence, confounds, and ongoing task ease confounds (see above for details).
