Table 3 Item difficulties and item-total correlations for RDF in the entire sample and in the group of IBS patients

1. Stomach pain

.62

.37

.36

.65

2. Relief through bowel movement

.52

.50

.30

.75

3. Passing gas

.71

.42

.41

.77

4. Stomach gas

.72

.68

.40

.83

5. Constipation

.41

.30

.25

.51

6. Diarrhoea or frequent bowel movement

.48

.18

.30

.57

7. Liquid stool

.41

.21

.73

.50

8. Hard stool

.41

.30

.26

.48

9. Urge to empty bowel

.59

.36

.37

.65

10. Feeling of complete emptying of the bowel

.62

.56

.34

.75

11. Feeling of fullness after meals

.55

.42

.31

.62

12. Prolonged feeling of fullness

.58

.39

.33

.65

13. Bloated stomach

.64

.51

.35

.77