Chapter 8. Design of the Main Survey Instruments

8.1 Introduction

The process of designing the NDA Questionnaire involved at the outset carrying out an in depth literature search of international instruments and methodological papers of recent years. The literature search produced many papers addressing methodological issues in the area of disability/activity limitation, which served to aid our design and planning process. A key aspect to the design process for us was how best to link the newest ICF Classification into our questionnaire in terms of the elements to choose and the level of detail necessary.

8.2 Review of Surveys

Initial designing of the disability questionnaire began with an analysis of international questionnaires. (A list of the instruments consulted is provided in Appendix 1). Three surveys were particularly important in the design of our questionnaire. These were the Survey of Disability, Ageing and Carers 2001, undertaken by the Australian Bureau of Statistics; the PALS 2001 Survey, undertaken by Statistics Canada and the New Zealand Household Disability Survey 2001, undertaken by Statistics New Zealand. A flavour of these surveys is provided below. All three surveys were analysed based on their content with regard to ICF chapters and domains and question typology. Broad categories based on the ICF domains were developed including:

  • Seeing
  • Hearing
  • Speaking
  • Mobility
  • Pain
  • Learning and Mental Functioning
  • Self Care & Domestic Life
  • Main Health Condition
  • Use of aids or specialised equipment
  • Social Participation
  • Transport and Education

The ICF was used as a conceptual framework in this design process. With the help of the consultation process decisions were made on the broad levels to be included.

For each category each survey was examined in terms of its inclusion/omission/ ICF classification and question typology. The questions spanned the components of functioning (Body Functions, Activities, Participation and Environmental Factors). As we wanted to target children (up to 15) influenced by international practices in this regard it was decided that this information would best be captured by devising a separate questionnaire for children.

Australian Bureau of Statistics – Survey of Disability, Ageing and Carers, 2001.

This survey measures information on people with disabilities, older people and people who provide assistance to others because of their disabilities. Information was recorded for adults and children. Information collected with regard to disability included such activities as self-care, mobility, communication, impairments and restrictions.

In 1998, 3.6 million people in Australia had a disability (19% of the total population). A further 3.1 million had an impairment or long-term condition that did not restrict their everyday activities. Of those with a disability, 87% (3.2 million) experienced specific restrictions in core activities, schooling or employment.

Statistics New Zealand – Household Disability Survey 2001

Statistics New Zealand carried out a second national household survey of disability in 2001. The first survey was carried out in 1996-1997. The new ICF disability classification was not used in the 2001 survey rather the older definition which had been used in the previous round was used instead for comparability purposes.

The sample size for the 2001 Household Disability Survey was 38,508 people. The achieved response rate was 73 percent. The total number of respondents with disabilities was 7,256; these were: 2,055 children; 3,483 adults aged 15 to 64 years; and 1,718 seniors aged 65 years and over.

The 2001 Household Disability Survey used four questionnaires. Adult and child screen questionnaires were firstly carried out to establish whether or not they had a disability according to the definition applied. Adults (aged 15 and over) and children (under 15) who fulfilled the criteria then completed an adult or child questionnaire. The questions related to services and assistance, employment, education, transport, accommodation, special equipment and economic characteristics. Two similar, but separate, questionnaires were completed for children aged 0 to 14 years who were selected to participate in the survey.

Statistics Canada Participation and Activity Limitation Survey (PALS) 2001

PALS is a post-censal survey, using the 2001 Census as a sampling frame to identify its population, designed in the light of the ICF. Two general questions on activity limitations were included on the 2001 Census and a sample of individuals who answered ‘yes’ to the activity limitation questions on the census form was selected.

The PALS sample was 43,000, consisting of approximately 35,000 adults and 8,000 children. The interviews were conducted by telephone. Two questionnaires were used, one for adults aged 15 and over and one for children under 15. The interviews for the children’s questionnaire were conducted with the parent or guardian of the child. The overall response rate was 82.5%.

8.3 Structure of Adult and Child Questionnaires

The structure of the adult and child questionnaires we developed were broadly similar. Both questionnaires contained each of the seven sections as outlined in Table 14 below. (The full questionnaires are given in Appendix 3 and 4 respectively) The main areas of differences between the two instruments related to issues such as marital status; labour market experience; transportation and driving; and intellectual development (extra questions added on this latter point on the child questionnaire).

Table 14: Section structure of adult and child questionnaires
SectionQuestionsComponentAdult QuestionnaireChild Questionnaire
1A1 to A10Activities & AidsSeeingSeeing
1B1 to B12Activities & AidsHearingHearing
1C1 to C8Activities & AidsSpeakingSpeaking
1D1 to D12Activities & AidsMobility / agilityMobility / agility
1E1 to E5Activities & AidsPainPain
1F1 to F6Activities & AidsBreathingBreathing
1G1 to G9Activities & AidsLearningLearning
1H1 to H3Activities & AidsIntellectual / development2 extra questions
1J1 to J3Activities & AidsMemoryMemory
1K1 to K3Activities & AidsEmotional, psychological, mental healthEmotional, psychological, mental health
1L1 to L4Activities & AidsAny other difficulty (specify)Any other difficulty (specify)
2M1 to M18Help from other people & attitudes of other people  
3N1 to N15Background to reduction in activities  
4P1 to P14Major Life AreasEducationEducation - extra questions on educational needs assessment
4Q1 to Q35Major Life AreasEmploymentEmployment - no questions
4R1 to R7Major Life AreasLeisure & social participationLeisure & social participation
4S1 to S17Major Life AreasTransportTransport - driving questions excluded
4T1 to T17Major Life AreasHousingHousing
5U1 to U16Demographic Information Marital status excluded
6V1 to V6Feedback from Respondent  
7W1 to W6Feedback from Interviewer  

As well as using the ICF as a conceptual framework to guide our design we also use it as a set of classifications. From Table 15 one can see the domains under each of the main components (Body functions and Structure A &P and Environmental Factors) the chapter, block and the broad 2 level 3 digit code.

On the main questionnaires, the ICF classification (without the qualifier) is printed in small font after each item that has a clear ICF counterpart (see Appendix 3 and Appendix 4). Since the relevant environmental factors tend to be specific to a particular set of circumstances, they are distributed throughout the questionnaire rather than forming a clear block of items. For instance, items A8 to A10 deal with aids or services that might be used by someone with a visual impairment; items D10 to D12 cover aids or services likely to be of benefit to someone with a mobility impairment.

Table 15: Breakdown of Questionnaire components into ICF Domains
ComponentSub-componentChapter2nd Level CodeClassification
Body functions & structuresVision2b210-b220Seeing & Related Functions
Body functions & structuresHearing2b230-b240Hearing & Vestibular Functions
Body functions & structuresSpeech3b310-b340Voice & Speech Functions
Body functions & structuresBreathing4b440-b460Functions of Respiratory System
Body functions & structuresPain2b280Pain
Activities & participationCommunication3d310 - d345Communication Receiving-Producing
Activities & participationMobility4d450-d465Walking and moving
Activities & participationAgility4d430 - d445Carrying, Moving & Handling Objects
Activities & participationSelf care5d510 - d570Self Care
Activities & participationMajor life areas - education8d810 - d839 
Activities & participationMajor life areas - employment8d840 - d859 
Activities & participationLeisure & social participation9d920 
Environmental factorsProducts & technology1e110 - e199 
Environmental factorsSupport & relationships3e310 - e399 
Environmental factorsAttitudes4e410 - e499 
Environmental factorsServices, systems & policies5e510 - e599 

As can be seen in Table 16, of the 143 people who said in the filter that they would take part 43 individuals (30 per cent) did not actually participate for a variety of reasons (mostly refusals) while 106 individuals (74 per cent) went on to complete the main survey. This figure was made up of 93 adults and 13 children.

Table 16: Response of 143 who supplied contact details
Completed Survey106*(74%)
Not available9(6%)

* 93 adults and 13 children

8.4 Piloting the Main Questionnaires

The main survey was implemented on a personally administered basis by interviewers visiting the respondents in their own home. In general, the experience of the pilot indicated a very positive response to the survey with very few problems arising.

Profile of (93) Adults


Table 17 indicates that the gender breakdown of adults interviewed was 58 per cent females, 42 per cent males.

Table 17: Gender Breakdown of Adults


An analysis of the age breakdown of the 93 participating adults is shown in Table 18. This indicates that 79 per cent of the sample was 45 yrs or over. The 45 to 64 age cohort accounted for the largest proportion overall (44 per cent), while the youngest age category (22 to 34yrs) accounts for the smallest proportion of adults surveyed (9 per cent).

Table 18: Age Breakdown of Adults
22-34 yrs8(9%)
45-64 yrs41(44%)
65 yrs33(35%)

Marital Status

Table 19 shows that 60 per cent of respondents were married. Widow/widowers account for 17 per cent of the sample, while single people make up 16 per cent, 5 per cent are separated and only one person was recorded as divorced.

Table 19: Marital Status of Adults.

Results from the Profile Sheet for Adults

In the course of each questionnaire the interviewer filled out a profile sheet which summarised the 11 broad categories in which the respondent reported having some level of difficulty. These broad categories are as follows:

  1. seeing
  2. hearing
  3. speaking
  4. mobility/agility
  5. pain
  6. breathing
  7. learning,
  8. intellectual/developmental,
  9. memory,
  10. emotional/psychological/mental health and
  11. any other activity limitation.

From Table 20 one can see that in general the type of activity limitation recorded most frequently was that of generic pain (77 per cent); this is followed closely by limitations in terms of mobility/agility, just one third of respondents identify breathing as a cause of activity limitation, nearly 30 per cent identified difficulties in hearing, 26 per cent can be seen to have some form of emotional psychological or mental health difficulty, while 24 per cent have difficulties in seeing. Between 4 to 11 per cent of adult respondents record difficulty with intellectual, developmental, learning and speaking.

Table 20: Activity Limitations as recorded on the Profile Sheet
Activity LimitationN%
Emotional, Psychological, Mental Health2426
Any other difficulty2729

Number of Activity Limitations experienced

As can be seen from the Table 21 a total of 3 per cent of respondents record no activity limitation. This can be explained by the fact that, as in the filter questionnaire, the main instrument recorded details on activity limitations and also participation restrictions; in effect this meant that a respondent could experience a) an activity limitation only; b) a participation restriction only or c) a combination of both. The 3% who reported experiencing no limitation in any of the 11 categories fall into the group - i.e. those who experience only participation restrictions. Just under half of respondents record an incidence of between 2 to 3, just over a quarter of respondents record the incidence of between 4 to 6 activity limitations, only 4 per cent (2) of respondents recorded between 7 or 8.

Table 21: Number of Activity Limitations recorded by respondents
Number of Activity LimitationsNumber of Respondents% of Respondents

Intensity Scale

In order to take account of the degree or intensity of difficulty experienced by respondents an intensity scale was developed. Altogether we had 11 disability types (10 distinct types and one miscellaneous “other” category). If the respondent recordedhaving a difficulty in any of the 11 disability types, the respondent was then asked to rate the level of difficulty which he/she experienced under one or more functional limitation categories associated with that disability. The nature of functional limitations varied as between one disability and the other.

For example, in the adult questionnaire 3 types of functional limitation was assessed for ‘hearing’ namely:

  • B2: Hearing what is said in a conversation with ONE other person
  • B3: Hearing what is said in a conversation with at least three other people, and
  • B4: Hearing what is said in a telephone conversation.

Another example is provided in the area of ‘Mobility/Agility’ where a total of 7 functional limitations were assessed:

  • D1: walking for short distances, such as walking around rooms or hallways or for short distances outside
  • D2: walking up and down a flight of stairs, about 12 steps without resting
  • D3: moving form one room to another
  • D4: getting into and out of bed
  • D5: lifting or carrying something like a cup or a bag of groceries
  • D6: bending down and picking up an object from the floor
  • D7: difficulty using your fingers to grasp or hold an object

Table 22 provides a breakdown of the number of functional limitations measured in each activity limitation category. A total of 20 functional limitations was assessed in terms of the respondents perception of their level of difficulty.

Table 22: Breakdown of Functional Limitations per Activity Limitation Category
Activity LimitationFunctional Limitations
Emotional, Psychological, Mental Health1
Any other difficulty1

The respondent could choose one from the response scale below (none to cannot do) to indicate the level of difficulty experienced in each of the 20 functional limitation categories:

Response ScalePoints attributed to each response
a little difficulty;1
a moderate level of difficulty;2
a lot of difficulty;3
cannot do.4

A score ranging from 0 – 4 was attributed in relation to each of the 20 functional limitations depending on the response given. The intensity score for each functional limitation across all respondents was then calculated as the mean score across each functional limitation. For adult respondents the intensity scale ranged from 0 to 2.3 points. These can be grouped into 4 categories as follows:

Intensity ScaleScore
Mildbetween 0.01 to 0.30
Moderatebetween 0.31 to 0.60
Severebetween 0.61 +

The results are outlined in Table 23. From this one can see that 9 per cent of adults (representing 8 persons) record a zero score on the intensity scale. These are individuals who recorded no activity limitation but who did indicate some form of participation restriction. The table shows that 24 per cent of respondents had “mild” score on the intensity scale (between 0.01 to 0.3); 29 per cent had a moderate score and the remaining 38 per cent had a “severe” score [2].

Table 24: Intensity of Adult Activity Limitation
Activity limitationN%

Intensity of Adult Activity Limitation by Gender and Age

Tables 25 and 26 provide a breakdown of adult respondents in terms of intensity scores according to gender, and age cohort. The breakdown by gender indicates little difference in intensity between males and females. As one might expect, intensity increases with age.

Table 25: Breakdown of Intensity Score by Gender
Male4 (10%)7 (18%)13 (33%)15 (38%)39 (100%)
Female4 (7%)15 (28%)14 (26%)21 (39%)54 (100%)
Total8 (8%)22 (24%)27 (29%)36 (39%)93 (100%)
Table 26: Breakdown of Intensity score by Age
22-340 (0%)2 (25%)3 (38%)3 (38%)8 (100%)
35-441 (9%)6 (54%)2 (18%)2 (18%)11 (100%)
45-643 (7%)9 (22%)11 (27%)18 (44%)41 (100%)
65+4 (12%)5 (15%)11 (33%)13 (39%)33 (100%)
Total8 (9%)22 (24%)27 (29%)36 (39%)93 (100%)

Profile of Children

Nine of the children interviewed in the main survey were male and 4 were female. With regard to age, Table 27 shows that the largest age cohort represented was 10-15 yrs, this was followed closely by 6-9 yr olds the lowest age cohort 3-5yrs accounted for the smallest proportion.

Table 27: Age Breakdown of Children
3-5 yrs2
6-9 yrs5
10-15 yrs6

Table 28 shows that disabilities/difficulties associated with children were more generally characterised as being related to hearing and developmental issues as well as communications.

Table 28: Activity Limitations as recorded on Profile Sheet
Activity LimitationN
Emotional, Psychological, Mental Health3
Any other difficulty6


  1. The total is greater than 100 per cent as in many cases more than one limitation was recorded.
  2. The reader is reminded that the labels mild; moderate; severe are arbitrary.