What Is QOL?

  2.  » Response Shift Example

What is QOL?

Quality of life is a concept including multiple aspects of people’s lives, such as:

  • Health
  • Material comforts
  • Personal safety
  • Relationships
  • Learning
  • Creative expression
  • Opportunity to help and encourage others
  • Participation in public affairs
  • Socializing
  • Leisure

Quality of life is defined by the World Health Organization as “an individual’s perception of their position in life in the context of the culture and value systems in which they live and in relation to their goals, expectations, standards and concerns.

What is Health Related Quality of Life?

Health related quality of life (HRQL) is the health aspect of quality of life that focuses on people’s level of ability, daily functioning and ability to experience a fulfilling life.

Examples of factors that can impact a person’s HRQL include:

  • Disease
  • Injury
  • Impairment
  • Health perceptions
  • Health care and treatments
  • Policy

Why is HRQL research important?

HRQL research helps people understand how health, disease and treatment impact quality of life.

People are then better able to, for example :

  • Understand the potential benefits and risks of a proposed treatment
  • Weigh the impact of a decision on symptoms, function and life expectancy
  • Live their lives more fully

An understanding of quality of life and HRQL also enables health program developers and policy makers to better allocate resources.

How do researchers study HRQL?

Researchers use assessments (interviews, surveys, questionnaires, scales) and symptom tracking to help determine life quality. Sometimes researchers collect this information directly from patients. Other times, researchers take a multi-perspective approach, collecting feedback from patients, their caregivers, clinicians and observers, health-related devices, and other sources.

Researchers, clinicians, patients, health policy experts, and others with a vested interest in health care study ways for people around the world to assess and improve their HRQL.

What does HRQL research involve?

ISOQOL works to advance three primary areas of HRQL research: theory, methods and application.


Theories summarize important concepts and their relationships to other concepts. HRQL researchers use theories to describe and explain the experiences of people who are affected by health conditions. This helps researchers understand findings, as well as identify and develop future studies needed to advance HRQL research, health care and policy. Theoretical research can include:

  • Efforts to explain known associations and relationships in HRQL literature
  • Modifications or extensions to theories routinely or historically used in HRQL research and application
  • Applications of an established theory from another field of research (e.g., philosophy, communication or economics) to HRQL research

Strong theoretical research provides direction for methods and application research.


Researchers study methodology to find or improve ways to collect and evaluate patient-reported health status. Methods research can also focus on ways to analyze and interpret data from health assessments.


Application research includes three different domains of empirical research, including:

  1. Clinical Research
    Researchers who conduct clinical research use patient-centered measures to better understand the nature, prevention, treatment and management of specific health conditions.
  2. Clinical Care
    Researchers who study clinical care applications attempt to better integrate the patient voice in real-world clinical encounters through the use of clinical outcome assessments to improve the effectiveness and efficiency of health care.
  3. Policy
    Researchers who study policy applications focus on HRQL issues relevant to the requirement, development and large-scale application of clinical outcome assessments in health care practice, regulatory and population/surveillance settings. This research often includes program evaluations, case studies, and economic analyses.

Theory, Methods and Application: Response Shift as an Example

Defining Response Shift

Sometimes the impact of a treatment aimed at improving the HRQL of a patient is defined by the difference between measurements at a baseline and follow-up assessments.1

In this scenario, HRQL researchers would point out that a person’s perception of HRQL can change over time due to a change in values, redefinition of factors impacting HRQL, or even when no other changes occur. These researchers are referring to a phenomenon called response shift.2


Researchers conducting theoretical research on response shift might examine existing studies to reveal assumptions and flaws or clarify concepts and definitions associated with the phenomenon in methodological, applicational and other theoretical studies.3


Methodological research on response shift might examine how the collection and interpretation of patients’ data accounts for response shift. These studies might also assess the validity of methods used to identify and measure response shift.4


In application research focused on response shift, researchers often examine how response shift affects how patients with the same health conditions report the effects of a treatment.

“Now I know what ‘exhausted’ means. Before treatment I thought I was exhausted, but now I realize I was merely tired at that time.” – Early-stage breast cancer patient undergoing radiotherapy5

  1. Friedrich, M., Karoff, J., & Hinz, A. (2019). Response shift effects in patients’ assessments of their quality of life after cardiac rehabilitation. Quality of Life Research28(9), 2609–2620. doi: 10.1007/s11136-019-02195-9
  2. Mayo, N. E. (Ed.). (2015). Response Shift. In Dictionary of Quality of Life and Health Outcomes Measurement (1st ed., pp. 125–126). ISOQOL.
  3. McClimans, L., Bickenbach, J., Westerman, M., Carlson, L., Wasserman, D., & Schwartz, C. (2013). Philosophical perspectives on response shift. Quality of Life Research22(7), 1871–1878. doi: 10.1007/s11136-012-0300-x
  4. Visser, M. R. M., Oort, F. J., & Sprangers, M. A. G. (2005). Methods to detect response shift in quality of life data: A convergent validity study. Quality of Life Research14(3), 629–639. doi: 10.1007/s11136-004-2577-x
  5. Jansen, S. J. T., Stiggelbout, A., Nooij, M. A., Noordijk, E. M., & Kievit, J. (2000). Response shift in quality of life measurement in early-stage breast cancer patients undergoing radiotherapy. Quality of Life Research9(6), 603–615. doi: 10.1023/A:1008928617014

The International Society for Quality of Life Research (ISOQOL) is a global community of researchers, clinicians, health care professionals, industry professionals, consultants, and patient research partners advancing health related quality of life research (HRQL).

Together, we are creating a future in which patient perspective is integral to health research, care and policy.