Calculation of the Global Index Score (GIS) of CIVIQ-20
There are 20 questions in the CIVIQ-20, each with 5 possible answers (1 to 5), the minimum possible score being 20 and the maximum 100. In order to calculate the GIS, the difference between the final score and the minimum possible score is to be divided by the difference between the theoretical maximum and minimum scores (100-20=80), multiplied by 100.
GIS = ([Final score – minimal possible score] / [Theoretical maximal – minimal score]) x 100
GIS = ([Final score – minimal possible score] / 80) x 100
GIS = ([Final score – 20] / 80) x 100
Example CIVIQ-20:
Score obtained from the 20 items questionnaire: 40.
The calculation is the following: 40-20=20. This number should be divided by 80: 20/80=0.25, then multiplied by 100. The GIS is 25.
In order to make GIS increasing when the quality of life is improving, scores can be inverted and 25 become 75. (100-25=75).
Calculation of the Global Index Score (GIS) of CIVIQ-14
There are 14 questions in the CIVIQ-14, each with 5 possible answers (1 to 5), the minimum possible score being 14 and the maximum 70. In order to calculate the GIS, the difference between the final score and the minimum possible score is to be divided by the difference between the theoretical maximum and minimum scores (70-14=56), multiplied by 100.
GIS = ([Final score – minimal possible score] / [Theoretical maximal – minimal score]) x 100
GIS = ([Final score – minimal possible score] / 56) x 100
GIS = ([Final score – 14] / 56) x 100
Example CIVIQ-14:
Score obtained from the 14 items questionnaire: 40.
The calculation is the following: (40-14) / 56 = 26 / 56 = 0.46, then multiplied by 100. The GIS is 46; or (100-46=54) depending on the adopted convention.