Self-assessment has been used to assess second language proficiency; however, as sources of measurement errors vary, they may threaten the validity and reliability of the tools. The present paper investigated the role of experiences in using Japanese as a second language in the naturalistic acquisition context on the accuracy of the…

Newer statistical procedures are typically introduced to help address the limitations of those already in practice or to deal with emerging research needs. Quantile regression (QR) is introduced in this paper as a relatively new methodology, which is intended to overcome some of the limitations of least squares mean regression (LMR). QR is more…