The measurement system, under development since 1988, is a comprehensive collection of patient reported measures that assess general health-related quality of life (HRQoL) and specific disease- and treatment-related concerns across multiple chronic illnesses and the general population. The measurement system (originally referred to as the Functional Assessment of Cancer Therapy, or FACT) emerged from a conceptual framework for quality of life in the context of health status that is centered on two essential principles: subjectivity and multidimensionality. HRQoL is uniquely personal, defined by patient experiences and influenced by one’s subjective perspective. Therefore, HRQoL is best assessed by direct-report. HRQoL is multidimensional, including, but not limited to symptoms, side effects, and functional status. It also includes more general appraisals of life quality and value. Meaningful assessment comes from asking patients about these distinct, yet often correlated areas of function and well-being. There is general consensus that key domains of HRQoL include physical, functional, emotional, and social/family well-being. Physical well-being refers to perceived and observed bodily function or disruption and includes symptoms such as pain, fatigue, and nausea. Functional well-being refers to one’s ability to perform the activities related to one’s personal needs, ambitions, or social role and includes things like ability to work, sleep, and enjoy life. Emotional well-being covers positive and negative affect as well as life enjoyment and appreciation. Social/family well-being includes a broader range of perceived support, leisure activities, family wellbeing, and intimacy. Over time, this framework
has expanded to include additional targeted domains such as disease-specific symptoms and treatment side effects for more comprehensive and clinically relevant assessment

Validation of the core measure allowed for the evolution of multiple disease, treatment, condition, and other targeted measures. FACIT scales are constructed to complement the FACT-G, addressing relevant disease-, treatment-, or condition-related issues not already covered in the general questionnaire. Each is intended to be as specific as necessary to capture the clinically-relevant problems associated with a given condition or symptom, yet general enough to allow for comparison across diseases, and extension, as appropriate, to other chronic medical conditions.

The FACIT Measurement System now includes over 700 items, some of which have been translated into more than 80 languages. Assessment of any one patient is tailored so that the most-relevant questions are asked and administration time for any one assessment is usually less than 15 minutes. The majority of FACIT items have demonstrated face and content validity and were created with direct input from patients and expert clinicians.

More recently, FACIT has expanded its catalog of items to the FACIT Searchable Library, where one can create a custom form using the site’s Build-a-PRO function and include only those FACIT items most relevant to one’s study or purpose. While doing so does not instantly validate the custom composition, it does create an opportunity to select specific items relevant to the research question at hand, using content valid items that have undergone careful translation into other languages. It also allows for the opportunity to pursue validation of the assembled set of questions using standard questionnaire validation practice.

The practice of selecting an established, fixed FACIT measure is still recommended for any investigator or clinician wishing to obtain a valid, interpretable score on the endpoints provided by that FACIT measure.