 The purpose of this study is to determine whether baricitinib 4 milligram mg once daily QD is superior to placebo in the treatment of participants with moderately to severely active Rheumatoid Arthritis RA who have had inadequate response to or are intolerant to at least 1 conventional disease-modifying antirheumatic drug cDMARDcDMARD-IR inadequate response participants and who have not received a biologic disease-modifying antirheumatic drug DMARD. 