Table 3 Stepwise approach to main scale item removal using exploratory factor analysis and Cronbach’s alpha

 OIP70

My OCD is likely to be permanent rather than temporary

Inspection of correlation matrix showed this item highly correlated (.825) with OIP67. OIP67 retained due to lower missing data.

 OIP14

My symptoms get worse when my daily routine needs to change^a

No factor loadings above .3

 OIP13

My symptoms are worse when I am in particular places^a

No factor loadings above .3

 OIP2

I find it hard to separate what is ‘me’ and what is my OCD^a

No factor loadings above .3

 OIP35

My OCD gets worse when I have more time^a

No factor loadings above .3

 OIP22

My OCD makes me obsessive about things in general, such as my hobbies and interests^a

No factor loadings above .3

 OIP9

My symptoms of OCD are affected by my physical health^a

No factor loadings above .3

 OIP24

My OCD makes me feel guilty^a

No factor loadings above .3

Factor 1: OIP48 – Other people’s behaviour can make my OCD worse^a

Item reduction of consequences scale - α reduced .001 when removed.

Factor 1: OIP10. My OCD gets worse when I need to conceal my symptoms^a

Item reduction of consequences scale - α reduced .001 when removed.

Factor 5: OIP26. Hearing or talking about OCD could lead to me picking up new symptoms^a

No change in α if removed.