1. Development of the WPAI
The rationale for the selection of the items in the WPAI is desribed here.
2. Permission to use the WPAI:
Written permission is neither required nor provided to researchers using the WPAI; there are no fees to use the WPAI or the translations on this webiste. We ask users to notify us when they publish or present WPAI data so we can list this information. See WPAI References.
3. Modifying questionnaire wording:
The questionnaire cannot be called the WPAI if questions or responses are changed or questions are added or deleted. Other related questions, e.g., occupation, job satisfaction, administered at the same time as the WPAI, should not be incorporated into the WPAI questionnaire or referred to as WPAI questions.
Please use the WPAI versions available on this website. See WPAI:GH and WPAI:SHP. The essential content of the questionnaires has not changed over time, but there have been minor adjustments in wording and formatting to make the versions consistent with each other in order to facilitate their translation into other languages.
4. Adapting the questionnaire to a specific disease/health problem:
The WPAI can be adapted to a specific disease or health problem; if there are no other changes the resulting instrument can be referred to as the WPAI. Users are cautioned that although the discriminative validity and reproducibility of the specific health problem (SHP) version has been established, evidence for evaluative validity and responsiveness to clinically meaningful change has only been established for a few diseases, e.g., allergies, chronic hand dermatitis, IBS, Crohn's disease. See validation studies. Researchers who use the WPAI for a new disease/condition are urged to include validity testing in the analysis and to share those results with other users.
When adapting the WPAI:SHP to a specific health problem, the name of the problem, e.g., constipation, leg pain, allergic rhinitis, should be inserted wherever the word PROBLEM appears in the template.
While it is theoretically possible to use the SHP version for any condition or problem, it is not adviseable to use it for systemic diseases, complicated conditions or in circumstances where it is unlikely that subjects can correctly attribute productivity loss or activity impairment to the disease. The SHP is most appropriate for limited or local conditions, e.g., chronic hand dermatitis. Disease such as diabetes and MS are best assessed with the General Health (GH) version.
5. Reformatting the questionnaire:
The WPAI can be reformatted (e.g., different font, boxes or blanks) to make it consistent with other instruments used in a study or for electronic entry. (See for example electronic entry.) Instructions to the subject for marking responses should be revised accordingly. However, users should be aware that such changes may potentially affect the questionnaire's performance.
The WPAI has been translated into more than 100 languages through a harmonization process consisting of several independent translations, back translations, expert review of the back translation, and local review by users.
The WPAI:SHP varies by the disease/condition of interest and has been translated for several diseases. For each new disease/condition the existing language template (if available) is used to create a disease specific version and the translation and harmonization process is repeated. In this way, the standardization of the translation from disease to disease is insured and researchers can reference current and future validation work in support of their methodology. See WPAI Translations.
7. Classroom Impairment:
Validation results for allergy-specific classroom impairment measures, modeled on the allergy-specific work impairment measures (WPAI-AS), are presented in: Reilly MC, Tanner A, Meltzer EO: Work, classroom and activity impairment instruments: validation studies in allergic rhinitis. Clinical Drug Investigations. 1996; 11(5):278-288. See WPAI:AS.
8. Caregiver version:
Several researchers have used a caregiver version of the WPAI, e.g., the effect of a child's specific health problem on the parent's work productivity, the effect of the patient's Alzheimer's disease on the partner's productivity. See caregiver studies.
9. Interviewer Administration:
The recall period in all WPAI validation studies is 7 days. The general literature on recall burden suggests that a longer recall period would not be suitable for the type of information being elicted with the WPAI. In therory, a shorter recall period would improve accuracy of WPAI responses, but this has not been tested.
11.Referencing the WPAI:
The WPAI should be referenced with:
Reilly MC, Zbrozek AS, Dukes EM. The validity and reproducibility of a work productivity and activity impairment instrument. PharmacoEconomics 1993; 4(5):353-65.