Measuring job stress in transportation workers: psychometric properties, convergent validity and reliability of the ERI and JCQ among professional drivers

Table 3 ERI-10 factor scoring parameters and variable ranges

Variable/Factor	No.	Number of items	Items involved	Calculation formula	Range
Root Factors
Efforts	F1	3	1,2,3	(ERI1 + ERI2 + ERI3)	[3–12]
Rewards	F2	7	4,5,6,7,8,9,10	(ERI4 + (5-ERI5) + (5-ERI6) + (5-ERI7) + ERI8 + ERI9 + ERI10)^a	[7–28]
Effort-Reward Imbalance (ERI) Indicator^b
Effort-Reward Imbalance (ERI)	F3	10	F1,F2	K(F1/F2) = ((7/3)(F1/F2))^c	–

Notes: ^aAssuming that items ERI5, ERI6 and ERI7 (measured in the scale 1–4) have not been previously reversed; ^bRepresents the imbalance ratio between Efforts and Rewards, or ERI; ^cBeing K = (# items on F2/ # items on F1)

ISSN: 1471-2458