Table 6.

Internal consistency reliability for the ILQI score

	Cronbach’s alpha
	ILQI score (N = 1506)
Cronbach’s alpha (total)	0.933
Cronbach’s alpha if variable deleted
1. How often has your ITP impacted on your working life or studies?	0.926
2. How often have you taken time off work or education because of your ITP?	0.930
3. How often has your ITP impacted your ability to concentrate on everyday tasks?	0.924
4. How often has your ITP impacted your social life?	0.925
5. How often has your ITP impacted your sex life?	0.929
6. How often has your ITP impacted your energy levels?	0.927
7. How often has your ITP impacted your undertaking of daily tasks?	0.923
8. How often has your ITP impacted your ability to support people close to you?	0.927
9. How often has your ITP negatively impacted your hobbies?	0.925
10. How often has your ITP negatively impacted your normal capacity to exercise?	0.926