Scoring the PFDI-20:
Scale Scores: Obtain the mean value of all of the answered items within the corresponding scale (possible value 0 to 4) and then multiply by 25 to obtain the scale score (range 0 to 100). Missing items are dealt with by using the mean from answered items only.
One may also ask, how is PFIQ 7 calculated?
Pelvic Floor Impact Questionnaire –Short Form 7 (PFIQ 7)
Scale scores: Obtain the mean value for all of the answered items within the corresponding scale (possible value 0- 3) then multiply by (100/3) to obtain the scale score (range 0 to 100). Missing items are dealt with by using the mean from answered items only.