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Table 4 The score range, mean as well as floor and ceiling effects and skewness of each item in the final version of the Visual Analogue Scale for Irritable Bowel Syndrome (VAS-IBS), as scored by the participating women (n = 71).

From: Development and psychometric testing of the Visual Analogue Scale for Irritable Bowel Syndrome (VAS-IBS)

VAS-IBS

Score Range*

Mean (SD)

Floor effects %

Ceiling effects %

Skewness

Physical symptoms

     

   Abdominal Pain

0–100

46.5 (29.4)

4.2

7.0

0.444

   Diarrhoea

0–100

60.0 (34.3)

7.1

20.0

-0.283

   Constipation

0–100

58.8 (32.9)

2.8

12.7

-0.226

   Bloating and Flatulence

0–100

33.3 (27.1)

8.5

1.4

0.774

   Vomiting and Nausea

0–100

66.1 (33.8)

4.2

25.4

-0.543

Mental health

     

   Perception of mental well-being

0–100

53.2 (30.0)

5.5

5.6

-0.044

Quality of Life

     

   Influence daily life **

0–80

43.6 (29.2)

18.8

0

-0.297

  1. The limit of the floor and ceiling effect was set at 20% or less and the skewness should be between -1 and +1 to be acceptable. 0 = worst symptom/health and 100 = best symptom/health
  2. ** n = 16