Table 6.

Ridge regression analysis between the number of scarlet fever cases and each NPI in mainland China from January 2011 to May 2022.

	Coeff	S.E.	t	p	Std. coef	VIF
c1	−497.895	731.038	−0.681	0.497	−0.060	1.309
c2	−670.791	582.133	−1.152	0.251	−0.078	0.777
c3	−638.506	315.099	−2.026	0.045	−0.085	0.297
c4	−609.591	368.837	−1.653	0.101	−0.081	0.404
c5	−67.180	1,025.133	−0.066	0.948	−0.006	1.628
c6	−83.115	758.895	−0.110	0.913	−0.010	1.316
c7	−410.545	498.746	−0.823	0.412	−0.052	0.676
c8	−742.939	843.410	−0.881	0.380	−0.087	1.641
Constant	5,241.198	916.078	5.721	0.000	0.000	0.000

Eight specific NPIs in OxCGRT's containment and closure policy: school closures (c1), workplace closures (c2), cancellation of public events (c3), restrictions on public gatherings (c4), closures of public transport (c5), stay-at-home requirements (c6), restrictions on internal movements (c7), and international travel controls (c8).