Clementini et al. (2003; C03) presented new B and V photometry and spectroscopy of RR Lyrae variable stars in two LMC fields. They derived an average metallicity of [Fe/H] = -1.48 ± 0.03 dex in good agreement with other estimates, and a luminosity-metallicity slope of 0.21 ± 0.05 mag/dex (in the sense that the most metal-poor RR Lyrae stars are brightest). C03 obtained a reddening-corrected magnitude of V0 = 19.06 ± 0.06 mag. Benedict et al. (2002b) used HST/FGS3 to measure the parallax of RR Lyrae itself ([Fe/H] = -1.39 dex) and derived MV = 0.61 ± 0.11 mag. Di Fabrizio et al. (2003) made a Baade-Wesselink analysis of CM Leonis ([Fe/H] = -1.91 dex) and obtained MV = 0.47 ± 0.04 mag. Adopting C03's estimate of the metallicity slope, the weighted average calibration is MV = 0.56 ± 0.04 mag at [Fe/H] = -1.48 dex. The C03 value for V0 thus implies µ0 = 18.50 ± 0.07 mag.
The most recent use of MACHO data to derive the LMC distance is based on first-overtone RR Lyrae stars (Alcock et al. 2004). Including corrections for blending and crowding bias based on artificial star tests, the MACHO data yield µ0 = 18.43 ± 0.06r ± 0.16s mag (C. Clement & A. Muzzin, priv. comm.). C03 compared their RR Lyrae V data with MACHO data and found an average of difference of -0.17 and -0.01 mag in their fields A and B, respectively (their magnitudes minus MACHO). However, Alcock et al. (2004) found only 7 RR Lyrae stars in common with C03 and these stars yielded an offset of +0.07 mag (C03 being fainter). Applying the crowding/blending correction yields an offset of -0.03 mag, which is consistent within calibration uncertainties.
Dall'Ora et al. (2003) recently obtained the first K-band data for LMC RR Lyrae stars in the Reticulum cluster and derived µ0 = 18.55 ± 0.07 mag. A subsequent analysis of these data yields a consistent but slightly lower distance modulus (G. Bono, priv. comm.). Finally, additional K-band data for field RR Lyrae stars near the LMC center yields µ0 = 18.48 ± 0.08 mag (Borrisova et al. 2004; J. Borissova, priv. comm.).