Figure 4.

Reliabilities of Probes Included in Established, Publicly Available DNA Methylation Algorithms (“Clocks”)

Distributions are depicted as box-and-whisker plots of the reliability coefficients of the probe constituents of the Hannum et al.³⁶ aging clock (63 probes), Horvath³⁷ DNAmAge clock (334 probes), and Levine et al.³⁸ biological aging clock (512 probes). Boxes correspond to IQR and whiskers extend to 1.5 × IQR. Observations beyond the whiskers (outliers) are represented by individual points. As a reference, the distribution (pink bars) and median (vertical dashed line) of all ∼440,000 probe reliabilities in the E-Risk dataset is shown above the box-and-whisker plots. The aging clocks are enriched for reliable probes (values to the right of the figure; NES, normalized enrichment score; N, number of probes). Median reliabilities of probes included in aging clocks are higher than those of the general distribution; however, each algorithm contained many unreliable probes.