# Presentation: 495375

## Analysis Plan

- Regional Meeting of UN Washington City Group on Disability Statistics
- Rio de Janeiro, Brazil
- September 19-20

## Objective

- To test the consistency of the Washington Group (WG) census questions in regards to how their interpretation may differ by:
- Different core domains
- Countries
- Subpopulations

## Step 1:  Construct Different Measures of Disability

- For ease of analysis we need binary variables
- To not lose richness of responses, we can used different definitions
- D1=1 if *some difficulty, a lot, or can’t do at all*
- D2=1 if *a lot of difficulty or can’t do at all*
- D3=1 if *can’t do at all*

## Functioning Matrix

| Core Domain | D1 | D2 | D3 |
| --- | --- | --- | --- |
| Vision |  |  |  |
| Hearing |  |  |  |
| Mobility |  |  |  |
| Remembering and Concentrating |  |  |  |
| Self-care |  |  |  |
| Communicating |  |  |  |

## Step 2: Compute Disability Prevalence

- Prevalence measured four ways:
- P1=1 if at least one domain has D1=1
- P2=1 if at least one domain has D2=1
- P3=1 if at least one domain has D3=1
- PM=1 if more than one domain has D1=2
- These prevalence rates can be compared with measures from previous country instruments to get a sense of what they are measuring relative to the WG questions

## Step 3: Construct Extended Measures

- Extended measures get at a deeper sense of how people are answering the core questions
- For example, for vision:
**Core question:**  *Do you have difficulty seeing, even if wearing glasses?*
**Extended questions: ***A) Do you have difficulty seeing and recognizing a person across the road?  B) Do you have difficulty seeing and recognizing an object at arm’s length?*** **

## Question Order

- In order not to “contaminate” the results of the WG questions, it is important that all six core questions be asked prior to the extended questions

## Constructing Extended Measures

- Within **each domain...**
- ED1 = 1 if at least one extended question in that domain has a response of *some difficulty, a lot of difficulty, or can’t do at all*
- ED2 = 1 if at least one extended question in that domain has a response of *a lot of difficulty or can’t do at all*
- ED3 = 1 if at least one extended question in that domain has a response of *can’t do at all*

## Step 4: Correlation analysis

- When people are answering the core questions, how does that relate to the underlying concepts in the extended questions?
- It could be that people respond positively to one set or questions but not the other, so define
**D0 = 1 if there are no reported difficulties**
**ED0 =1 if there are no reported difficulties in any of the extended questions **

## Correlation Matrix – (for each domain)

|  | ED0 | ED1 | ED2 | ED3 |
| --- | --- | --- | --- | --- |
| D0 |  |  |  |  |
| D1 |  |  |  |  |
| D2 |  |  |  |  |
| D3 |  |  |  |  |

## How do core and extended questions relate?

- Using correlation coefficients test if there are statistically significant differences between the D and ED measures
- D0 vs. ED0, D1 vs. ED1, etc.
- If they differ, then the measures are not equivalent
- If they aren’t equivalent,  does one set identify more people as disabled?

## Step 5: Differences by Subpopulation

- Older people
- Gender
- Rural vs. Urban
- Ability to examine subpopulations depends on sample size.