Quality of Life Index (QLI)

Abstract

The Quality of Life Index (QLI), specifically the Generic Version III, is a prominent self-report instrument developed by Carol Estwing Ferrans and Marilyn Powers in 1985. It is designed to provide a comprehensive, multidimensional assessment of subjective Quality of Life (QOL).

The QLI is unique in its approach as it measures two distinct components: the respondent’s level of satisfaction across various life domains, and the perceived importance of those same domains. This dual-component structure allows for the calculation of a weighted QOL score, ensuring that the final result is reflective of the individual’s personal values and priorities. The 33 items are grouped into four major subscales: Health and Functioning, Social and Economic, Psychological/Spiritual, and Family.

Keywords

Quality of Life Index, QLI, Quality of Life, QOL, Ferrans and Powers, Generic Version III, Satisfaction, Importance, Health, Psychosocial Assessment, Subjective Well-being.

Authors

Carol Estwing Ferrans, Marilyn Powers.

Purpose

The primary purpose of the Quality of Life Index (QLI) is to provide a comprehensive, preference-weighted assessment of an individual’s subjective quality of life. It moves beyond simple functional status measures by incorporating the respondent’s personal values regarding their life circumstances.

The QLI is widely utilized in clinical and research settings, particularly in nursing and health psychology, to track changes in well-being over time, evaluate the effectiveness of interventions, and compare QOL across diverse patient populations. Its generic format makes it applicable to the general population, while numerous adaptations exist for specific clinical groups (e.g., oncology, cardiology).

Construct

The QLI is grounded in a conceptual model that defines Quality of Life as a highly subjective phenomenon—the degree to which a person is satisfied with those aspects of life that are important to him or her. The construct measured is thus a composite of perceived satisfaction weighted by perceived importance.

The instrument operationalizes this construct through 33 paired items that map onto four key domains of life experience. The resulting weighted score offers a nuanced perspective that accounts for the discrepancy between one’s current state (satisfaction) and one’s ideals (importance), providing a robust measure of overall psychological and physical well-being.

Validity

Extensive psychometric testing has demonstrated strong evidence for the validity of the QLI. Content validity was established during development via expert review to ensure comprehensive coverage of domains relevant to QOL.

Construct validity has been supported through studies showing that QLI scores correlate appropriately with measures of related constructs, such as depression, functional status, and overall health. Furthermore, the instrument has proven effective in differentiating QOL levels between various groups, including healthy individuals and those suffering from chronic illnesses. The QLI has also been successfully translated and validated in numerous cultural contexts, supporting its broad applicability (e.g., the Persian version validated by Rafiei et al., 2010).

Reliability

The QLI exhibits high internal consistency, a critical component of reliability, across its subscales and the overall composite score. Cronbach’s alpha coefficients consistently meet or exceed acceptable standards in both clinical and non-clinical samples, confirming the homogeneity of items within each of the four identified domains.

Test-retest reliability has also been confirmed in several studies, indicating the stability of the measure over time, provided the underlying QOL status of the respondent remains unchanged. This stability is crucial for longitudinal research and clinical monitoring.

Factor Analysis

Initial and subsequent applications of Factor Analysis have consistently supported the hypothesized four-factor structure underpinning the QLI. These analyses confirm that the 33 items load onto four distinct, yet interrelated, subscales that represent the core components of the QOL construct as conceptualized by Ferrans and Powers.

The established dimensions derived from the factor analytic studies are:

• Health and Functioning Subscale
• Social and Economic Subscale
• Psychological/Spiritual Subscale
• Family Subscale

Instrument

Test Type: Self-report questionnaire, Preference-weighted measure.

Format: The QLI consists of 33 items, each rated on two separate 6-point Likert scales: Part I assesses Satisfaction (1=Very Dissatisfied to 6=Very Satisfied), and Part II assesses Importance (1=Very Unimportant to 6=Very Important).

Language Available: English (Original), Persian, and numerous other languages due to widespread international use and validation.

Population Group: Generic (designed for the general population but frequently adapted for specific clinical groups, such as those with chronic disease or cancer).

Age Group: Adults.

Population Details: Applicable to individuals in various health states, including healthy populations, hospitalized patients, and those undergoing long-term treatment.

Test Methodology: The final QLI score is calculated by weighting the satisfaction scores (Part I) by the corresponding importance scores (Part II) for each item. This preference-weighting methodology ensures that the final index score reflects the respondent’s subjective valuation of their life domains.

Keywords

Subjective Well-being, Health Measurement, Nursing Research, Psychometric Properties, Self-Report, Weighted Scoring, Clinical Assessment.

Authors

Author ORCID Identifier: Not provided in source content.

Affiliation Email addresses: [email protected]

Correspondence Address: Carol Estwing Ferrans, PhD, FAAN, University of Illinois at Chicago, College of Nursing (M/C 802), 845 S. Damen Avenue – 7th floor, Chicago, IL 60612 U.S.A. Phone (312) 996-8445, Fax (312) 996-4979.

Permissions & Fee and Test Year

The Quality of Life Index was initially developed and published in 1985 (Ferrans & Powers). For information regarding usage permissions, licensing fees, and access to specific versions of the QLI, researchers are instructed to contact the author directly via email or consult the official instrument website: http://www.uic.edu/orgs/qli/.

Reference’s

1. Ferrans, C. (1996). Development of a conceptual model of quality of life. Scholarly Inquiry for Nursing Practice: An International Journal, 10(3), 293-304.
2. Ferrans, C., & Powers, M. (1985). Quality of Life Index: Development and psychometric properties. Advances in Nursing Science, 8, 15-24.
3. Ferrans, C., & Powers, M. (1992). Psychometric assessment of the Quality of Life Index. Research in Nursing and Health, 15, 29-38.
4. Ferrans, C. E. (1990). Development of a quality of life index for patients with cancer. Oncology Nursing Forum, 17(3), 15-19.
5. Warnecke, R., Ferrans, C., Johnson, T., et. al. (1996). Measuring quality of life in culturally diverse populations. Journal of the National Cancer Institute Monographs, 20, 29-38.
6. Rafiei.Narges, Sharifian Sani. Maryam, Rafiey. Hassan, Behnampour. Nasser, Foroozesh, Kian., (2010). Reliability and Validity of Persian Version of “Quality of Life Index”. J Mazandaran University Med Sci 2014; 24(116): 75-83 (Persian).

Items of the Quality of Life Index (QLI)

IMPORTANT: The following scale items must be preserved in their original language and must not be changed in any way.

Part I

1=Very Dissatisfied‚ 2=Moderately Dissatisfied‚ 3=Slightly Dissatisfied‚ 4=Slightly Satisfied‚ 5=Moderately Satisfied‚ 6=Very Satisfied

HOW SATISFIED ARE YOU WITH:

1. Your health?
2. Your health care?
3. The amount of pain that you have?
4. The amount of energy you have for everyday activities?
5. Your ability to take care of yourself without help?
6. The amount of control you have over your life?
7. Your chances of living as long as you would like?
8. Your family’s health?
9. Your children?
10. Your family’s happiness?
11. Your sex life?
12. Your spouse‚ lover‚ or partner?
13. Your friends?
14. The emotional support you get from your family?
15. The emotional support you get from people other than your family?
16. Your ability to take care of family responsibilities?
17. How useful you are to others?
18. The amount of worries in your life?
19. Your neighborhood?
20. Your home‚ apartment‚ or place where you live?
21. Your job (if employed)?
22. Not ha‎ving a job (if unemployed‚ retired‚ or disabled)?
23. Your education?
24. How well you can take care of your financial needs?
25. The things you do for fun?
26. Your chances for a happy future?
27. Your peace of mind?
28. Your faith in God?
29. Your achievement of personal goals?
30. Your happiness in general?
31. Your life in general?
32. Your personal appearance?
33. Yourself in general?

Part II

1= Very Unimportant‚ 2=Moderately Unimportant‚ 3=Slightly Unimportant‚ 4=Slightly Important‚ 5=Moderately Important‚ 6=Very Important

HOW IMPORTANT TO YOU IS:

1. Your health?
2. Your health care?
3. ha‎ving no pain?
4. ha‎ving enough energy for everyday activities?
5. Taking care of yourself without help?
6. ha‎ving control over your life?
7. Living as long as you would like?
8. Your family’s health?
9. Your children?
10. Your family’s happiness?
11. Your sex life?
12. Your spouse‚ lover‚ or partner?
13. Your friends?
14. The emotional support you get from your family?
15. The emotional support you get from people other than your family?
16. Taking care of family responsibilities?
17. Being useful to others?
18. ha‎ving no worries?
19. Your neighborhood?
20. Your home‚ apartment‚ or place where you live?
21. Your job (if employed)?
22. ha‎ving a job (if unemployed‚ retired‚ or disabled)?
23. Your education?
24. Being able to take care of your financial needs?
25. Doing things for fun?
26. ha‎ving a happy future?
27. Peace of mind?
28. Your faith in God?
29. Achieving your personal goals?
30. Your happiness in general?
31. Being satisfied with life?
32. Your personal appearance?
33. Are you to yourself?