Table 4.

Sensitivity analysis and model validation

Panel A: sensitivity analysis of the DEA model
Variables/removed	Average scores		DMUs efficient (%)		p-value (Mann–Whitney)		Spearman rank correlation (sig.)
None	0.61		12.9%		–		–
Accounts payable	0.51		9.1%		3 × ${10}^{-13}$		0.832 (0.000)
Accounts receivable	0.54		7.5%		3 × ${10}^{-6}$		0.886 (0.000)
Cost of goods sold	0.51		8.6%		2 × ${10}^{-10}$		0.899 (0.000)
Inventory	0.57		8.1%		0.0226		0.938 (0.000)
Panel B: the distribution variance of efficiency scores
Year		p-value (Mann–Whitney)		p-value (Kruskal–Wallis)		Spearman rank correlation (sig.)
(2018–2019)		0.497		0.814		0.812 (0.000)
(2019–2020)		0.944				0.876 (0.000)
(2018–2020)		0.684				0.738 (0.000)