Manual
Administration
The FAQLQs are usually administered on paper. However, an online version of the FAQLQ-AF showed comparable measurement properties as the paper version [Goossens et al., 2011].
Special attention should be paid to the administration of the FAQLQ-CT for children aged 8-12 years. Parents and children should be instructed that the child should fill out the questionnaire themselves. Children may ask their parents for help, but parents are not allowed to tell the child which answer to give.
Items and domains
The number of items of each FAQLQ ranges from 23 to 30 items and each questionnaire consists of 3 to 4 domains (See Table 1). Each question of the FAQLQ is answered on a 7-point scale.
Table 1 Items and domains of the FAQLQs
| Questionnaire | Items (n) | Domains |
| FAQLQ-CF | 24 | Allergen avoidanceRisk of accidental exposureEmotional impactDietary restrictions |
| FAQLQ-TF | 23 | Allergen avoidance and dietary restrictionsEmotional impactRisk of accidental exposure |
| FAQLQ-AF | 29 | Allergen avoidance and dietary restrictionsEmotional impactRisk of accidental exposureFood allergy related health |
| FAQLQ-PF | 30 | Emotional ImpactFood-related anxietySocial and dietary limitations |
| FAQLQ-PFT | 27 | Emotional ImpactFood AnxietySocial restrictionsDietary restrictions |
Calculation of total FAQLQ scores and domain scores
Each question of the FAQLQ is answered on a 7-point scale (0 to 6) and should be recoded 1 to 7. Total FAQLQ scores and domain scores are calculated by dividing the sum of completed items by the number of completed items. Total FAQLQ and domain scores range from 1 “no impairment” to 7 “maximal impairment”. It is recommended to only calculate total FAQLQ and domain scores when 80% or more is completed.
Scoring sheets for calculating total FAQLQ scores and domain scores are available for the FAQLQs:
FAQLQ-PF scoring sheet (all age groups)
FAQLQ-PFT(teenagers) scoring sheet
Minimal Important Difference
The Minimal Important Difference (MID) of the FAQLQ is not yet known. The MID of health-related quality of life questionnaires with a 7-point scale is usually approximately 0.5 (Jaeschke et al., Control Clin Trials 1989;42:913-920)
Checking validity of FAQLQ with FAIM
Not all translations of the FAQLQ have been validated in the new language or country. Within a study it is possible to check the validity of the FAQLQ (e.g. in a new population or a cross-cultural setting) by calculating correlation coefficients between FAQLQ and Food Allergy Independent Measure (FAIM). The FAIM consists of six questions and measures the perceived disease severity of food allergy [van der Velde et al., 2010].
Each question of the FAIM is answered on a 7-point scale (0 to 6) and should be recoded 1 to 7. Total FAIM scores are calculated by dividing the sum of completed items by the number of completed items. Total FAIM scores range from 1 “low perceived disease severity” to 7 “high perceived disease severity”. It is recommended to only calculate total FAIM scores when 80% or more is completed.
Please contact us for assistance in validating a translation of the FAQLQ.