# Presentation: 717934

## Coding NCHS Survey Questions on Disability using the International Classification of Functioning,Disability, and Health

- Gerry E. Hendershot, Ph.D.
- Consultant on Disability and
- Health Statistics

**Notes:**
The purpose of this study was to determine the feasibility of coding disability data from NCHS surveys to categories of the International Classification of Functioning, Disability, and Health, also known as the ICF.  The work was supported by the Data Policy and Standards Staff at NCHS.  The Data Policy and Standards Staff is the organizational home of the World Health Organization Collaborating Center for the Classification of Diseases in North America.  The Collaborating Center is responsible for overseeing WHO’s “Family of Health Classifications,” which includes the International Classification of Functioning, Disability, and Health.

## Overview

- International Classification of Functioning, Disability, and Health (ICF)
- United Nations reporting categories
- Illustrations of coding NCHS survey questions to ICF categories
- Summary of NCHS survey coverage of ICF/UN categories

**Notes:**
I will begin be giving an introduction to the ICF as a theoretical framework and a classification system.  Then I will identify the nine broad types of disability for which the United Nations recommends that national statistical systems report estimates.  I will then illustrate how data from several NCHS surveys were coded to ICF categories corresponding to the UN disability types.  Finally, I will summarize the coverage in six NCHS surveys of the ICF/UN disability categories.  A written version of this report is available on request.

## The ICF

- Approved by World Health Assembly
- Available in six official languages
- Searchable Web and CD versions
- www.who.int/icidh

**Notes:**
After an eight year international process of development and testing, the ICF was approved in May 2001 by the World Health Assembly, the governing body of the World Health Organization.  It was subsequently published in all six of the official languages of the WHO, both on paper and electronically.  Web and CD-ROM versions are available with user-friendly search software.  Some training materials are available at the Web site and others are under development.  The Web site is www.who.int/icidh.

## Health Condition (disorder/disease)

**Notes:**
The ICF uses a conceptual framework that recognizes the underlying complexity of human functioning.  It sees human functioning as the result of interaction between the person and contextual factors. The person includes both the body (structure and function) and the individual (individual activity and social participation).  Contextual factors include both environmental factors and personal factors.  Health conditions, the person, and contextual factors mutually affect one another.  The ICF framework is similar to and consistent with other disability frameworks proposed in recent years.  The ICF framework, like others,  does not explain disability, but it identifies and names its main aspects.

## ICF

***Classification***

***Parts***

***Components***

***Domains and categories***
*** ******at different levels ***

**ICF**

**Part 1:**
**Functioning and Disability**

**Part 2:**
**Contextual Factors**

**Body Functions **
**and Structures**

**Activities **
**and**
**Participation**

**Environ-mental **
**Factors **

**Personal **
**Factors**
**(Not covered)**

**Item levels:**
**1****st**** **
**2****nd**
**3****rd**

**Item levels:**
**1****st**** **
**2****nd**
**3****rd**

**Item levels:**
**1****st**** **
**2****nd**
**3****rd**

**Notes:**
The main contribution of the ICF is not its conceptual framework, but its detailed classification of human functioning.  In theory, any function or disability can be assigned an ICF alpha-numeric code that identifies a functional category and a level of functioning.  The classification system has two main parts, corresponding to the person and contextual factors.  The person part has two components, corresponding to body (function and structure) and person (individual activity and social participation).  The contextual factors part also has two components, environmental factors and personal factors, but only the environment is included in the ICF.  Within each component are hierarchically arranged domains and categories at various levels of detail.

## d4500, Walking short distances

- d450, walking: Moving along a surface on foot, step by step, so that one foot is always on the ground, such as when strolling, sauntering, walking forwards, backwards, or sideways.
- d4500, walking short distances: walking for less than a kilometre, such as walking around rooms or hallways, within a building or for short distances outside.

**Notes:**
An example of an ICF functioning code may clarify the classification principles.  Here is an excerpt from the ICF for the code “d4500.”  The “d” indicates the person-level activity or participation part of the classification.  The “4” indicates the fourth chapter of that part, which is titled “Mobility.”  The “5” indicates a section in the Mobility chapter that is titled “Walking and moving.”  The first “0” following the 5 refers to the general definition of walking, and the second “0” indicates the first category of walking, “walking short distances.”  This code identifies the category of functioning, walking short distances.  Typically, it would be followed by a qualifier that would indicate the level of functioning, ranging from very high to very low.

## UN disability categories

- 1. ***Seeing***, even with glasses 2. ***Hearing***, even with aid
- 3. ***Speaking***, includes talking
- 4. ***Moving/***mobility, includes walking, climbing, standing
- 5. ***Body movement***, includes reaching, crouching, kneeling

- 6. ***Gripping***/holding, includes using fingers to grip objects
- 7. ***Learning***, including intellectual difficulties, retardation
- 8. ***Behavioral***, includes psychological, emotional
- 9. ***Personal care***, includes bathing, dressing, feeding

**Notes:**
The purpose of the study I am reporting was to see if is feasible to code disability data from NCHS surveys using the ICF classification system.  Because this was a feasibility study, not a full scale link between surveys and the ICF, it was limited to selected functional categories; specifically, the categories recommended by the United Nations for reporting by national statistical systems.  Based on its assessment of data needs and data collection capabilities in its member nations, the UN decided that it was both desirable and feasible for most nations to collect and report data on these nine functional categories: seeing, hearing, speaking, moving, body movement, gripping or holding, learning, behavior, and personal care.

## NHIS on walking

- By ***yourself*** and ***without using aids***, do you have any difficulty walking ***a quarter of a mile*** (that is about 2 or 3 blocks)?  [ If yes] How much difficulty do you have, some, a lot, or are you unable to do it?

**Notes:**
A sub-category of the UN category “moving,” is “walking short distances,” for which we have already seen the ICF definition.  For this study, we wanted to know if NCHS survey questions could be coded to that ICF category.  Here, for instance, is an NHIS question on walking.  Should it be coded to ICF code “d4500”?  Is the NHIS “quarter of a mile” equivalent to the ICF “less than a kilometre”?  What about the NHIS qualifications “by yourself” and “without using aids”?  In this case, I would accept the equivalence of “quarter of a mile” and “less than a kilometre.”  And the ICF code structure for severity has a way of accommodating the personal assistance and assistive technology issues.

## NHANES  on walking

- By ***yourself*** and ***without any*** ***special equipment***, how much difficulty do you have walking for a quarter of a mile [that is about 2 or 3 blocks]?  No difficulty, some difficulty, much difficulty, unable to do?

**Notes:**
Here is the NHANES question most consistent with ICF code d4500, “Walking short distances.”  It is very similar to the NHIS question.  That’s not just coincidence: when the most recent NHANES was being designed, there was an explicit effort to make its household survey questions as comparable to the NHIS as possible.  There are, however, small differences.  The NHIS says “aids” whereas the NHANES says “special equipment.”  The NHIS first asks if there is any difficulty, and then ask for the amount of difficulty; the NHANES asks only one question about all levels of difficulty, including none.  Do these question differences make a difference in the data?  Should question wording be standardized in the two surveys?

## b230, hearing functions

- Sensory functions relating to sensing the presence of sounds and discriminating the location, pitch, loudness and quality of sounds.

- Inclusions: functions of hearing, auditory discrimination, localization of sound source, lateralization of sound, speech discrimination; impairments such as ***deafness, hearing impairment and hearing loss**** *

**Notes:**
Here is another ICF code example, b230, “hearing functions.”  The “b” refers to body functioning.  The “2” refers to chapter 2, titled “Sensory Functions and Pain.”  The “30” refers to the section of that chapter on hearing functions.  Most domain codes at this level have statements about “inclusions” and sometimes “exclusions” that help coders to avoid some common errors.  In this case, “deafness” is specifically included. 

## LSOA on hearing

- Do you NOW have ***deafness in both ears***?  Deafness in one ear?  Any other trouble hearing with one or both ears?

**Notes:**
And here is a question from the Longitudinal Studies on Aging on deafness: “Do you NOW have deafness in both ears?  Deafness in one ear?  Any other trouble hearing with one or both ears?”  Notice that the LSOA question begins by asking about the most serious impairment, deafness in both ears, and then asks about less serious hearing impairments.

## NNHS on hearing

- Does ... have any difficulty in hearing (when wearing a hearing aid)?  Is ...”s hearing (when wearing a hearing aid) partially, severely, or completely impaired, as defined on this card?
-   	***Deaf: “can hear only a few words a person says or loud noises.” ***

**Notes:**
Here is a question on hearing from the National Nursing Home Survey : “Does ... have any difficulty in hearing (when wearing a hearing aid)?  Is ...s hearing (when wearing a hearing aid) partially, severely, or completely impaired, as defined on this card?”  Notice that the NNHS question begins with the least severe impairment and then asks about more serious impairments, exactly opposite to the LSOA question on hearing.  Notice also that the NNHS question asks about hearing when using a hearing aid, if one is used.  The LSOA questions does not specify that condition.  As I said before, the ICF does have a coding convention for the severity that allows for distinguishing between the use or non-use of assistive technology such as a hearing aid.

## NCHS surveys covered in study

| Nat’l Health Interview Survey |  |
| --- | --- |
| Nat’l Health & Nutrition Exam. Survey |  |
| Longitudinal Studies of Aging |  |
| Nat’l Nursing Home Survey |  |
| Nat’l Home & Hospice Care Survey |  |
| Nat’l Mortality Followback Survey |  |

**Notes:**
In the study I am describing, questions about functioning were examined in the six surveys listed here: the National Health Interview Survey, the National Health and Nutrition Examination Survey, the Longitudinal Studies of Aging, the National Nursing Home Survey, the National Home and Hospice Care Survey, and the National Mortality Followback Survey. There are other NCHS data systems that have collected disability data, but these are the most important NCHS sources of such data.  For each survey, the most recent questionnaires were examined, and questions about functioning in the nine UN-recommended disability types were assigned to the ICF code that matched best.

## NCHS Coverage of ICF/UN Categories

| See |  |  |  |  |
| --- | --- | --- | --- | --- |
| Hear |  |  |  |  |
| Speak |  |  |  |  |
| Move |  |  |  |  |
| Body |  |  |  |  |

**Notes:**
One question that can be asked is: to what extent do NCHS surveys cover the nine UN-recommended disability topics?  This graphic and the next answer that question for four of the six surveys in the study, indicated by their icons: they are the NHIS, the NHANES, the LSOA, and the NNHS.  I left out the other two surveys just to save space and time.  This graphic shows which surveys have questions on seeing, hearing, speaking, mobility, and body movement.  The NHIS has questions on all five types of function, the NHANES and LSOA have questions on four of the five, and the NNHS has questions on three of the five.

## NCHS Coverage of ICF/UN Categories

| Grip |  |  |  |  |
| --- | --- | --- | --- | --- |
| Learn |  |  |  |  |
| Behave |  |  |  |  |
| Care |  |  |  |  |
| All |  |  |  |  |

**Notes:**
This graphic shows which of the four surveys has questions on gripping, learning, behavioral problems, and personal care-taking.  The NHIS has question on all four of these functions, the NHANES and LSOA have questions on three of the four, and the NNHS has a question on one of the four.  The NHIS was the only one of the six surveys examined that has questions on all nine of the UN-recommended disability types.

## In conclusion . . .

**Notes:**
This study has shown that it is feasible to code disability data collected by NCHS surveys to categories in World Health Organization’s International Classification of Functioning, Disability and Health.  It has also identified some gaps and inconsistencies in disability data collection, gaps and inconsistencies that could be remedied in future surveys. NCHS continues to participate in WHO’s worldwide efforts to improve disability classification, and NCHS is also participating in a UN-led effort to improve survey and census measures of disability.