Ruscio and colleagues (Ruscio, Seaman, D'Oriano, Stremlo, & Mahalchik, this issue) provide a thoughtful empirical analysis of 22 different measures of individual scholarly impact. The simplest metric is number of publications, which Simonton (1997) found to be a reasonable predictor of career trajectories. Although the assessment of the scholarly contribution of a candidate for tenure is unlikely to be favorable if there are no or very few scientific publications, the number of publications is a far-from-perfect index of scientific contribution. Moreover, the incentives created by a metric such as number of publications may not promote the quality, innovativeness, programmatic nature, and cumulative impact of the research. Ruscio et al. (this issue), therefore, used five criteria to evaluate metrics of science: (1) ease of understanding; (2) accuracy of calculation; (3) effects of incentives; (4) influence of extreme scores; and (5) validity. Given the computational aids available today, the first 2 metrics are perhaps the least important and the third and fifth are most important. One of the interesting results of the empirical analyses performed by Ruscio et al. is that self-citations have nominal impact on the outcomes, a finding that increases the confidence in the validity and simplifies the calculation of these metrics. Perhaps the best metric to emerge in Ruscio et al.'s (this issue) analysis is the "h" index (Hirsch, 2005). This metric provides a single number that balances the number of publications and the number of citations per publication. The "h" index has limitations, of course. Among them are that the "h" index tends to increase with years as a scientist; gratuitous authorship can contribute to inflated scores; the "h" index does not take into consideration the number or the role of the authors; different citation databases provide different "h" indexes as a result of differences in coverage; the "h" index is bounded by total number of publications; the "h" index does not consider the context of the citations (e.g., negative findings or retracted work); and individuals with the same "h" index may nevertheless differ dramatically in total citations or in number of publications.