Objective. To analyse seven RA Core Data Set measures and three indices for their capacity to distinguish treatment results in early RA in the GUEPARD treat-to-target clinical trial vs ESPOIR routine care. Methods. Post hoc analyses compared 65 GUEPARD and 130 matched control ESPOIR patients over 6 and 12 months for mean changes in measures, relative efficiencies and standardized response means (SRM). Three indices—28-joint disease activity score (DAS28), clinical disease activity index (CDAI) and routine assessment of patient index data (RAPID3)—were compared for mean changes and numbers of patients with high, moderate or low activity or remission using κ values. Results. Greater improvement was seen for GUEPARD vs ESPOIR, statistically significant for physician and patient global estimates and pain and health assessment questionnaire physical function (HAQ-FN), but not joint counts and laboratory tests. Relative efficiencies with tender joint count as the referent measure indicated that pain (2.57) and global estimates by patient (3.13) and physician (2.31) were most efficient in distinguishing GUEPARD from ESPOIR. Mean improvements in GUEPARD vs ESPOIR were −3.4 vs −2.6 for DAS28 (0–10) (24%), −29.8 vs −23.1 for CDAI (0–76) (23%) and −13.0 vs −7.8 for RAPID3 (0–30) (40%) (all P < 0.01); agreement was moderate between CDAI vs DAS28 (κ = 0.56) and vs RAPID3 (κ = 0.48), and fair between DAS28 vs RAPID3 (κ = 0.26). Conclusion. Patient and global measures indicate greater efficacy than joint counts or laboratory measures in detecting difference between GUEPARD treat-to-target and ESPOIR routine care. A RAPID3 of only patient measures may help guide treat-to-target in busy clinical settings.