Table 6

Model assessment

Increase in count	Clinical		Clinical damage in hands and feet		Radiological
Increase in count	Observed	Predicted	Observed	Predicted	Observed	Predicted
(A) Observed increases in damaged joint counts
0	4436	4432.3	4726	4721.5	627	644.7
1–4	5293	5305.9	5381	53393.6	1218	1193.3
5–10	152	135.9	107	90.6	132	130.7
>10	61	64.3	37	40.8	31	57

Increase in joint count	Centile of the prediction score
(B) Estimated probabilities of new damage over a 2-year period
	10%	30%	50%	70%	90%
0	0.821	0.760	0.693	0.637	0.583
1–4	0.165	0.201	0.222	0.226	0.221
>4	0.014	0.039	0.085	0.137	0.195