Table 2

Overall levels of evidence of measurement properties per instrument across all included studies

InstrumentInternal consistencyReliabilityMeasurement errorContent validityStructural validityCross-cultural validityHypothesis testingCriterion validityResponsivenessInterpretability
RADAI10 20 21 25 42 54 55 57–59++
0.84–0.91 α		?
0.92 ICC		?
14.9%maxSDD		?++
1 factor		?+++−−
0.48–0.83s		++
0.77 AUCresponder		?
RADAI-521 22 24 39 53++
0.91–0.92 α		???++
1 factor		?++++
0.62–0.66s		–
0.589s/0.295κ		?
PDAS I9–
0.5 α		+
0.76–0.88		????++
0.89s		??
PDAS II9–
0.4 α		+
0.76–0.88		????++
0.76s		??
Pt-DAS2810–13 45?+
0.92p		+
23.2%meanSSD		???++++
0.73–0.94p		±?
Pt-SDAI11 45?+
0.90p		+
59.9%meanSSD		???+++
0.87s 0.93p		??
PAS I26 54??????+?+
0.79 AUCresponder		?
PAS II26??????+???
RAPID 223??????????
RAPID 322 38–41 43 46 48–52 54–56 59++
0.87 α		?
0.90		?
14.8%maxSDD		?++
1 factor		?++++
0.64–0.91s		±
0.80 AUCresponder
0.43–0.53 wκ		?
RAPID 4 PtJC23 38 51???????++
0.65s		??
RAPID 4 MDJC23??????????
RAPID 523 51 58???????++
0.69–0.71s		+
0.70s		?
PRO-CLARA54 55+
0.89 α		???+
1 factor		?++
0.84s		+
0.82 AUCresponder		?
PRO-Index C/M47????????+?
GAS44 58???????−−
0.54s		–
0.50s		?

  • +, positive result; −, negative result (for explanation of the categorisation of the levels, see table 3); %maxSDD, SDD as percentage of maximum value of outcome; %meanSDD, SDD as percentage of mean value of the outcome; α, Cronbach's α; τ, Kendall's τ; AUCflare, area under the curve for patients with flare versus no flare; AUCresponder, area under the curve for patients responding to therapy versus not responding; GAS, Global Arthritis Score; ICC, interclass correlation coefficient; MDJC, Medical Doctor Joint Count; p, Pearson's correlation coefficient; PAS, Patient Activity Score; PDAS, Patient-based Disease Activity Score; PRO-Index C/M, Patient Reported Outcome-index continuous (C) & majority (M); Pt-DAS28, Patient-derived Disease Activity Score with 28-joint counts; PRO-CLARA, Patient Reported Outcome CLinical ARthritis Activity; PtJC, Patient Joint Count; Pt-SDAI, Patient-derived Simplified Disease Activity Index; RADAI, Rheumatoid Arthritis Disease Activity Index; RAPID, Routine Assessment of Patient Index Data; s, Spearman's correlation coefficient; SDD, smallest detectable difference; wκ, Weighted Kappa.