Comparison of RRL mean-magnitude changes between different surveys. Each panel shows the OGLE-IV, OGLE-III, MACHO, EROS-2, MOA, and KMTNet light curves (black, blue, brown, purple, green, and red dots, respectively; see their descriptions in Appendix A) after subtraction of (separate) Fourier light-curve models for each dataset. Light curves are offset by arbitrary amounts for clarity. The overlaid orange dots and lines show the mean-magnitude change modeling according to the light-curve fits, similarly to panel (e) of Fig. 1. Above the panels, the OGLE ID, the pulsation period, the amplitude of the mean-magnitude changes, and the measured amplitude ratio r_I, V = A(I)/A(V) are given for the corresponding RRL, based on the OGLE-IV data.