Frequently Asked Questions
- Is the CDC HRQOL instrument free and are there any copyright restrictions?
- Is the Spanish-language version of the CDC HR-QOL instrument free and are there any copyright restrictions?
- Where can I find examples of computer syntax to score the measures?
- Can I use the HRQOL-14 for my thesis or dissertation?
- How does CDC gather data on HRQOL?
- Has the CDC HRQOL-14 been used in clinical populations?
- How do I calculate unhealthy days using BRFSS data?
- How do I calculate unhealthy days using my own HRQOL data?
- Where can I get a copy of the CDC Health-Related Quality of Life monograph?
- What is your official definition of Frequent Mental Distress (FMD)?
- Which cutpoints can I use to look at Frequent Mental Distress or Frequent Physical Distress?
- Where can I find information on the psychometric properties of the HRQOL measures?
- Where can I find a list of surveys that have used the CDC HRQOL measures?
- How can I obtain a copy of the following validation study of the CDC HRQOL measures: Newschaffer CJ. Validation of Behavioral Risk Factor Surveillance System (BRFSS) HRQOL measures in a statewide sample. Atlanta: US Department of Health and Human Services, Public Health Service, Centers for Disease Control and Prevention, National Center for Chronic Disease Prevention and Health Promotion, 1998?
- Is the CDC HRQOL instrument free and are there any copyright restrictions?
The HRQOL instrument is free for public use. The measures were developed with federal funding, are not copyrighted, are in the public domain, and do not require permission for use or licensing fees. The instrument is available for public use in both English and in Spanish.
Top of Page - Is the Spanish-language version of the CDC HR-QOL instrument free and are there any copyright restrictions?
The Spanish-language version of the HRQOL-14 is free for public use. There are no copyright restrictions. For an example of the construct validity of the measures in the Hispanic population, please see our article: Centers for Disease Control and Prevention. Health-Related Quality of Life Puerto Rico, 1996-2000, available in English and in Spanish.
Top of Page - Where can I find examples of computer syntax to score the measures?
You will find information on how to score the instrument in Methods and Measures. You can also find SAS, SPSS, and SUDAAN syntax that might be helpful to you to correctly recode the variables.
Top of Page - Can I use the HRQOL-14 for my thesis or dissertation?
Because the survey is in the public domain and free for anyone to use, you are very welcome to use it for your thesis or dissertation. If you do publish your work, please send an e-mail request to Contact CDC-INFO and include a citation to that work for inclusion in our list of publications that use the measures.
Top of Page - How does CDC gather data on HRQOL?
CDC gathers data on health-related quality of life (HRQOL) using either telephone interviews or face-to-face interviews with persons who agree to participate in surveys of representative populations of state or US residents. The surveys most often used regularly for this purpose are the Behavioral Risk Factor Surveillance System (BRFSS) State-based telephone survey of adults 18 years old or older, and the National Health and Nutrition Examination Survey (NHANES), a face-to-face interview of a nationally representative sample of adolescents and adults.The main four-question “core” HRQOL questionnaire used on these surveys is on the Methods and Measures page. Another set of questions expands on the domains of this questionnaire to activity limitations and healthy days symptoms. Occasionally, some or all of these HR-QOL questions have been used in other nationally representative surveys (for example, the General Social Survey).A few other points:- Besides the four “core” health-related quality of life questions present on all the annual BRFSS since 1993, ten additional related questions have been asked in some States from 1995 through 2005. These data are available for certain states on the main data set.
- The BRFSS surveys are complex sample surveys requiring appropriate software for analysis accounting for the survey design (stratification, weighting, etc.). Not taking account of the survey design underestimates variances for parameters like means, proportions, and regression coefficients. Therefore, it is necessary to use software that accounts for the survey design (SUDAAN™, SASTM version 9.1+ survey programs, SPSS™ Complex Samples module, STATA™ survey procedures, etc.; mention of these software programs here does not constitute endorsement of these programs by the CDC).
- Has the CDC HRQOL-14 been used in clinical populations?
The instrument has been used in routine clinical practice and has been shown to have good predictive and construct validity in clinic populations. For additional information, please see:- Currey SS, Rao JK, Winfeild JB, Callahan LF. Performance of a generic HRQOL measure in a clinic population with rheumatic disease. Arthritis & Rheumatism. 2003;49:658-664. (This study found that the the HRQOL-14 was able to detect differences in HRQOL among diagnosis groups (e.g., fibromyalgia, rheumatoid arthritis, osteoarthritis.)
- Dominick K, Gold C, Ahern F, & Heller D. Cardiac drug use & health-related quality of life among older men and women. The Gerontologist 1999;39(1):244.
- Conway S, Gold, Dominick K, Ahern F, & Heller D. (2001, March 21st–24th). Mental health-related quality of life (HRQOL) measures as predictors of cardiac hospitalization. Presentation at the 22nd Annual Meeting of the Society of Behavioral Medicine, Seattle, WA.
- Currey SS, Rao JK, Winfield JB, Callahan LF. Variations in health status among rheumatic disease patients using the BRFSS health-related quality of life measure. Arthritis and Rheumatism 2000;43:(9 Suppl S):662.
- Gold C, Dominick K, Ahern F, Heller D. Medication use and health-related quality of life among the elderly (abstract). The Gerontologist. 2000;40:345.
- Gold C, Dominick K, Ahern F, Heller D, & Conway S. (2001, March 21st-24th). Health-related quality of life (HRQOL) and psychotropic medication use in older adults with diabetes. Presentation at the 22nd Annual Meeting of the Society of Behavioral Medicine, Seattle, WA.
The limits associated with using our instrument in clinical practice, however, lies primarily in the potential difficulty in assessing the responsiveness of the measure following a therapeutic intervention. Our questions are designed to measure broad influences on life, including more distal social and environmental factors such as housing, income, social support, and access to care. Following a clinical intervention (e.g. surgery for seizures) a person can have a significant improvement in health (e.g., seizure reduction/elimination) but due to other influences (e.g., unemployment, low levels of social support) might still report poor HRQOL. Unfortunately, we have not yet been able to conduct sufficient numbers of studies in clinical populations to assess the instrument’s responsiveness following an intervention.
- How do I calculate unhealthy days using BRFSS data?
SAS™, SPSS™ and SUDAAN™ are statistical computer software packages that are used to analyze data. SAS™ and SPSS™ are used for general analytical purposes (e.g., descriptive statistics, analytical statistics). While SUDAAN™ can be used for descriptive and analytical statistics of simple random samples, it is specifically designed for correlated data such as the data used by the CDC, and US state and local health departments. The software code available on our website is made available to the public so that investigators interested in analyzing CDC datasets can do so easily and with more limited measurement error associated with coding of the variables.Important points regarding scoring are- Self-rated health — while one can examine each level of this variable, one can combine good, very good, excellent into one category, and fair or poor into another category for analysis.
- Physically unhealthy days — compute a mean for your population; code those that respond “don’t know/not sure” as missing values.
- Mentally unhealthy days — compute a mean for your population; code those that respond “don’t know/not sure” as missing values.
- Activity limitation days — impute (i.e., recode) a “zero” for this item for those that respond that they have no physically unhealthy days and no mentally unhealthy days; code those that respond “don’t know/not sure” as missing values.
- Unhealthy days — you should sum physically unhealthy days (PUDs) and mentally unhealthy days (MUDs) with a maximum value of 30 (for 30 days per month). In other words, if PUDs + MUDs is greater than 30, recode this value to 30.
- How do I calculate unhealthy days using my own HRQOL data?
If you asked this set of questions of two separate, independent simple random samples and would like to make comparisons between the two samples, the standard way of making comparisons using these variables would be to calculate the mean number of physically unhealthy days, mentally unhealthy days, and unhealthy days for both groups and use an independent sample to test and assess any statistically significant differences in these measures between the two groups. For the self-rated health question, you could use a Chi-Square test to test for significant differences between groups on nominal level data or other, more sophisticated methods to test for significant differences on the ordinal level. - Where can I get a copy of the CDC Health-Related Quality of Life monograph?
You can download a copy of the HRQOL Measuring Healthy Days monograph [PDF-1.4MB]. Top of Page - What is your official definition of Frequent Mental Distress (FMD)?
Frequent mental distress is defined as having 14 or more mentally unhealthy days as measured by the CDC Healthy Days question: Now thinking about your mental health, which includes stress, depression, and problems with emotions, for how many days during the past 30 days was your mental health not good? For additional supporting documentation, including a reference supporting this cut-point, please see our article, where you will find the following text:This 14-day minimum period was selected because a similar period is often used by clinicians and clinical researchers as a marker for clinical depression and anxiety disorders, and a longer duration of reported symptoms is associated with a higher level of activity limitation (Milazzo-Sayre LJ, Henderson MJ, Manderscheid RW. Serious and severe mental illness and work: what do we know? In: Bonnie RJ, Monahan J, eds. Mental Disorder, Work Disability, and the Law. Chicago, Illinois: University of Chicago Press;1997).For a number of publications that have used the Frequent Mental Distress measure, please see the Publications page. Top of Page - Which cutpoints can I use to look at Frequent Mental Distress or Frequent Physical Distress?
There is no definitive answer to your question and no real standard set of categories other than our common use of the 14+ days grouping to indicate a substantial level of impairment. You are free to use any reasonable categorization scheme based on 1) the response distribution to the questions, 2) hypothesized or empirically established levels of severity, 3) or comparability with public domain prevalence data tables or published research. We have not yet done a systematic review of the literature to document what categories have been used, but we will consider doing that in the future. Fewer groups provide larger sample sizes for testing significant differences and tend to show a more stable dose-response pattern. In general, if you include at least 50 responses per cell, this will provide narrower confidence intervals and more stable prevalence estimates over time. Top of Page - Where can I find information on the psychometric properties of the HRQOL measures?
You can find information on the psychometric properties of the HRQOL measures on the Publications page. Top of Page - Where can I find a list of surveys that have used the CDC HRQOL measures?
You can find information on surveys that have used the HRQOL measures on the Publications page. Top of Page - How can I obtain a copy of the following validation study of the CDC HRQOL measures: Newschaffer CJ. Validation of Behavioral Risk Factor Surveillance System (BRFSS) HRQOL measures in a statewide sample. Atlanta: U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control and Prevention, National Center for Chronic Disease Prevention and Health Promotion; 1998?
Download the validation report [PDF-30MB]. To request a copy of the following validation study of the CDC HRQOL measures, contact us by mail at: Centers for Disease Control and Prevention Health Related Quality of Life Surveillance Program, 4770 Buford Hwy, NE, MS F78, Atlanta, GA 30341 or send an email request to Contact CDC-INFO. Top of Page
