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Although older adults are keeping their teeth longer, no national data are available on new caries in this age group. To characterize the extent of caries among older adults, we systematically reviewed studies on root caries incidence, increment, attack rate, and annual total (root + coronal) caries increment. We used a random-effects model to estimate annual summary measures and their 95% confidence intervals (CI) and tested for heterogeneity. For the 9 studies reporting root caries incidence, the summary measure equaled 23.7% (CI = 17.1-30.2%). For the 9 studies reporting root caries increment, the summary measure was 0.47 surfaces (CI = 0.34-0.61). For the 7 studies reporting total caries increment, the summary measure equaled 1.31 surfaces (95% CI = 1.01-1.61 surfaces). Because of heterogeneity, summary measures should be interpreted with caution. This research suggests, however, that older adults experience high rates of new caries and could benefit from caries-prevention programs.

In this paper, we address the problem of finding the simulated system with the best (maximum or minimum) expected performance when the number of alternatives is finite, but large enough that ranking-and-selection (R&S) procedures may require too much computation to be practical. Our approach is to use the data provided by the first stage of sampling in an R&S procedure to screen out alternatives that are not competitive, and thereby avoid the (typically much larger) second-stage sample for these systems. Our procedures represent a compromise between standard R&S procedures-which are easy to implement, but can be computationally inefficient-and fully sequential procedures-which can be statistically efficient, but are more difficult to implement and depend on more restrictive assumptions. We present a general theory for constructing combined screening and indifference-zone selection procedures, several specific procedures and a portion of an extensive empirical evaluation.

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