Table 12.

Model validity test—Spearman rank correlation (Across years)

	2009	2010	2011	2012
2009	–	–	–	–
2010	0.632	–	–	–
2011	0.854*	0.572*	–	–
2012	0.848*	0.665*	0.784*	–

*P value < 0.05