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Frequently Asked Questions about NHIS-CAM


Below, you can find answers to frequently asked questions about the NHIS and NHIS Child CAM Survey. If you would like to access more general questions about the Data Resource Center, please see our DRC FAQ page.

To quickly orient yourself to the NHIS Child CAM content and design, see the following “fast fact” guides:

Common NHIS and NHIS Child CAM Supplement questions

What is the Child Complementary and Alternative Medicine (CAM) Supplement?
What is the National Health Interview Survey (NHIS)?
What are the components of the NHIS?
Who sponsors the Child CAM Supplement?
When was the child CAM data collected in the NHIS?
How do I receive assistance if I am having a hard time interpreting output from the NHIS-Child? 

Availability of NHIS-Child CAM data

How can I get NHIS Child CAM survey results?
Are the NHIS data files available to the public? What data files are available?
Is state level data available in the NHIS survey?
How can the NHIS data files be merged?

NHIS-Child CAM Supplement Methodology

What is the sampling frame of the NHIS?
Where can I find information about the sampling and administration methods used for the NHIS?
How are children selected for the Sample Child Core and Child CAM Supplement? 

NHIS CAM Supplement Topics

What topics are asked about in the 2012 Child CAM Supplement?
What CAM modalities are asked about in the 2012 Child CAM Supplement?
Why is prayer not asked about?
What is new in the 2012 Child CAM Supplement compared to the 2007 Supplement

Definitions and Measure Development

What CAM modalities are included in the “CAM use definition” in the DRC data query?
What are the groupings of the CAM modalities asked about in the Supplement?
How is the CAM use for children with specific conditions assessed?
How were out-of-pocket costs for CAM practitioners/providers/instructors estimated?
How was number of visits to CAM practitioners/providers/instructors defined, if the response was a categorical range? 

Common NHIS and NHIS Child CAM Supplement questions

What is the Child Complementary and Alternative Medicine (CAM) Supplement?

The Child CAM Supplement is one of the National Health Interview Survey (NHIS) Supplements and collects information about non-conventional health services, products, and practices commonly used. Estimates are nationally representative of the noninstitutionalized child population in the United States. 

What is the National Health Interview Survey (NHIS)?

NHIS is a health interview survey of the US civilian, non-institutionalized household population. The survey has been conducted continuously by the National Center for Health Statistics (NCHS) of the Centers for Disease Control and Prevention (CDC) since 1957.

What are the components of the NHIS?

The NHIS, which was last redesigned in 1997, consists of a Basic Module and variable Supplements. The Basic Module consists of three components: the Family Core, the Sample Adult Core and the Sample Child Core. The Family Core component collects information about everyone in the family, including information about socio-demographic characteristics, health, activity limitations, injuries, health insurance coverage, use of and access to health care services. The Sample Adult and the Sample Child Cores obtain additional information on health status, health care services and behaviors for a randomly selected adult or child from each family. 

Who sponsors the Child CAM Supplement?

The National Center for Complementary and Integrative Health (NCCIH - former National Center for Complementary and Alternative Medicine - NCCAM) of the National Institutes of Health provided the primary funding for the Child CAM Supplement. The National Center for Health Statistics (NCHS) of the Centers for Disease Control and Prevention (CDC) oversaw the sampling, telephone interviews and data management for the supplement.

When was the child CAM data collected in the NHIS?

The Supplement was administered in the NHIS for the first time in 2007 and again in 2012.

How do I receive assistance if I am having a hard time interpreting output from the NHIS-Child CAM Supplement?

The DRC makes it easy to receive technical assistance for questions related to understanding data and using our website. Just ask us a question. The DRC staff makes every effort to respond to your email within 2 to 3 business days.

Availability of NHIS-Child CAM Supplement data

How can I get NHIS Child CAM survey results?

The Data Resource Center website lets you interactively browse NHIS Child CAM data, and provides point-and click access to NHIS Child CAM survey results in tabular and graphical formats. We also provide merged NHIS/NHIS Child CAM Supplement datasets, and resources to analyze the data.   

Are the NHIS data files available to the public? What data files are available?

Yes. Datasets with the variables appearing on the Data Resource Center website’s interactive data query are available at no cost in SPSS format. For more information, contact info@cahmi.org. NCHS released 13 data files for the 2012 NHIS: six core data files, a paradata file, the three Disability Questions Tests files, a Functioning and Disability file, and two Complementary and Alternative Medicine files. These data files can be downloaded as ASCII files and programs to read the ASCII files into SAS, SPSS, and Stata at no cost from the NCHS website

Is state-level data available in the NHIS and Child CAM Supplement?

State-level estimates can be produced for states with large populations. State identifier information is not publicly released, but can be obtained through the National Center for Health Statistics (NCHS) Research Data Center (RDC).

How can the NHIS data files be merged?

The dataset accessible through the DRC is the merged dataset of Household, Family, Imputed Income, Person, Sample Child, and Child CAM Supplement data files.

The NHIS public-use data files downloaded from the NCHS website can be merged using the household (HHX), family (FMX) and person (FPX) record identifiers. The sample SAS code to merge data files can be found in the “NHIS Survey Description” at the NCHS website.

NHIS-Child Methodology

What is the sampling frame of the NHIS?

NHIS uses a multistage area probability sampling design that incorporates stratification, clustering and oversampling of Blacks, Hispanics and Asians. The NHIS sampling design allows for a data collection process that is nationally representative of US households and noninstitutional group quarters (e.g., college dormitories). The sampling plan is redesigned after every decennial census. The current sampling plan was implemented in 2006.

Where can I find information about the sampling and administration methods used for the NHIS?

What questions are in the surveys? Can I see the final questionnaire that was used? Who is in the survey, how are they chosen? Are the results representative of US children? Answers to these questions can be found in the Survey Methodology section of our website.

How are children selected for the Sample Child Core and Child CAM Supplement?

One child age 0-17 years (if any) was randomly selected from each family to be the subject of the Sample Child Core questionnaire. Of those, children ages 4-17 years old were also the subject of the 2012 Child CAM Supplement. In the 2007 Child CAM Supplement, children ages 0-17 years were included.

NHIS-Child Topics

What topics are asked about in the 2012 Child CAM Supplement?

The 2012 Child CAM Supplement asks about use of 34 specific CAM modalities that may or may not require a practitioner or instructors. The supplement collects information on use of CAM modalities, insurance coverage and out-of-pocket cost for visits to CAM practitioners, providers, classes or trainings, reasons for and benefits of CAM use, conventional medical care use for children who used CAM therapies for specific conditions, disclosure of CAM use to health care providers and sources of information about CAM.

What CAM modalities are asked about in the 2012 Child CAM Supplement?

The CAM modalities asked about in the 2012 Child CAM Supplement are: chiropractic or osteopathic manipulation, massage, energy healing therapy, acupuncture, naturopathy, ayurveda, chelation, craniosacral therapy, hypnosis, biofeedback, homeopathy, traditional healers (Native American Healer/Medicine Man, Shaman, Curandero/Machi/Parchero, Yerbero/Hierbista, Sobador, and Huesero), vitamins or minerals, herbal or non-vitamin supplements, meditation (Mantra, Mindfulness, Spiritual meditation), guided imagery, progressive relaxation, yoga, tai chi, qi gong, special diets (vegetarian, macrobiotic, Atkins, Pritikin, Ornish) and movement or exercise techniques (Feldenkrais, Alexander Technique, Pilates, and Trager Psychophysical Integration).

Why is prayer not asked about?

The NHIS Child section is answered by an adult in the family who is knowledgeable about the child’s health. National Center for Complementary and Alternative Medicine testing revealed that parents do not always know the answers to questions about motivations and behaviors related to their children, such as whether a child prays for his or her health. Questions on prayer were, therefore, not included.

What is new in the 2012 Child CAM Supplement compared to the 2007 Supplement?

In the 2012 Child CAM supplement, survey questions were asked only about children ages 4-17 years, and questions about craniosacral therapy, specific types of meditation, health insurance coverage and out-of-pocket costs were added. Reasons for and benefits of CAM use, conventional medical treatments received for conditions the CAM modality was used for, disclosure of CAM use to personal health care providers, and sources of information about CAM were included for the 2012 supplement.

Definitions and Measure Development

What CAM modalities are included in the “CAM use definition” in the DRC data query?

2007 NHIS data demonstrated that the estimated prevalence of CAM use among US children varies according to how the use of vitamins and minerals is included and scored. Many researchers do not consider vitamins and minerals to be CAM because vitamins/minerals are routinely used for preventive purposes. However, according to the 2007 NHIS, a significant number of children who experience chronic conditions used vitamins and minerals. Therefore, three versions of CAM use definitions were developed in the 2012 Child CAM Supplement data query:

  • 34 CAM modalities, including all vitamins and minerals
  • 34 CAM modalities, including specific vitamins and minerals but excluding multi-vitamins and multi-minerals
  • 33 CAM modalities, excluding all vitamins and minerals

What are the groupings of the CAM modalities asked about in the Supplement?

Thirty four specific CAM modalities asked about in the 2012 Survey were grouped into 2 types:

  • Grouping A: biologically based; mind-body, manipulative/body-based, alternative medical systems; and energy healing therapy.Energy healing therapy was combined with alternative medical systems due to small sample sizes.
  • Grouping B: categorizes modalities according to whether they represent products (e.g. herbs), practices (e.g. yoga) or services (e.g. acupuncture)

CAM groupings used for the DRC data query are available here

How is the CAM use for children with specific conditions assessed?

Use of CAM for children with specific conditions is assessed using the conditions asked about in the Sample Child Core due to validity issues with respect to asking about conditions or problems CAM was used for. Discordance between conditions child experienced versus conditions named as the reason for CAM use, and underestimation of CAM use for children with conditions were observed in the 2007 NHIS. One of possible reason could be that parents were less inclined to name specific conditions as the reason for their children’s CAM use, because children used CAM for overall health and wellbeing or for specific functional issues versus more discrete diagnoses. For more information click here (meta data report) 

How were out-of-pocket costs for CAM practitioners/providers/instructors estimated?

If the exact dollar amount paid out-of-pocket was unknown, out-of-pocket costs for practitioners/providers/instructors were calculated by multiplying the average amount paid per visit by the number of visits in the past 12 months.

How was number of visits to CAM practitioners/providers/instructors defined, if the response was a categorical range?

If the exact number of visits to a practitioner is unknown and number of visits was reported in categorical range, the midpoint of the interval was used to estimate number of visits to practitioner. For response category ‘‘more than 25 times,’’ the value of 26 was used.