This report presents further results based on the longitudinal findings from Wave One and Two of the Life Opportunities Survey (LOS). Initial findings were published in the Part I Report.Back to table of contents
The Life Opportunities Survey (LOS) is a large-scale longitudinal survey1 of disability in Great Britain and it is the first major national social survey which explores disability in terms of the barriers to participation that people experience. Prior to the development of the LOS, the last major survey on disability conducted in Great Britain had been the Family Resources Survey disability follow-up in 1996/97, and before that was the Office of Population Censuses and Surveys (OPCS) national surveys of disability carried out during 1985-88. In 2005, the Department for Work and Pensions (DWP) carried out a feasibility study2 which recommended a new survey dedicated to meet the evidence needs of the policy for disabled people in Great Britain. Subsequently, the Office for Disability Issues (ODI) (part of the DWP) commissioned the Office for National Statistics (ONS) to develop the LOS.
The survey is wholly funded by the DWP and is carried out by the ONS. Each wave of the survey spans two years and respondents in Wave Two have been followed up approximately one year after their initial interview. Wave One of the LOS took place between June 2009 and March 2011; Wave Two began in June 2010 and finished in March 2012.Back to table of contents
The following section of the report contains a brief summary of how respondents are followed up from Wave One to Wave Two, and how they are classified into groups for the purpose of longitudinal analysis.
Follow-up of respondents from Wave One to Wave Two
Each respondent’s impairment status at Wave One was used to assign them to one of three different groups which determined how they were followed up at Wave Two:
1. Adults with at least one impairment
This group included all adults who reported at least one impairment at Wave One (29%1). These adults, as well as all adult members of their households, were interviewed in person at Wave Two.
Of the 71% of adults who did not report having an impairment at Wave One, a subset was selected to form a ‘control’ group. The adults in this group were chosen to provide a comparison group that is similar to the adults with at least one impairment on several key characteristics associated with impairment – sex, age, region of residence, and the urban/rural classification of residence. The size of the control group was designed to be half that of the group of adults with at least one impairment, that is for the Wave Two sample there were two adults with impairment for every one person in the control group. All of the adults in the control group, as well as all adult members of their households, were interviewed in person at Wave Two.
All of the remaining adults who did not have an impairment at Wave One and who were not selected for the control group were assigned to the ‘onset screening group’. These adults were not interviewed in person at Wave Two, unless they or an adult member of their household had acquired an impairment between Wave One and Wave Two. A brief telephone interview was conducted with the onset-screening group between Wave One and Wave Two in order to establish if anyone in their household had acquired an impairment.
For more information on the composition of the three follow-up groups, see the Wave Two Interim Technical Report2.
Development of the control group for analysis
Although sub-sampling to identify adults for follow up at Wave Two was carried out at the individual level, interviews were conducted at the household level to simplify fieldwork procedures. Therefore, household members living with a respondent selected for follow up at Wave Two were also given a face to face interview. To utilise all the data collected and to make the control group represent the population of people who are not impaired, the co-residents were included in the control group for analysis purposes. This group is referred to as ‘adults without impairment at both waves’ in this report, and comprises of all adults who:
were chosen to be in the ‘control’ group and did not have an impairment at Wave Two,
did not have an impairment at Wave One and Wave Two but were living in the same household as an adult chosen to be in the ‘control’ group, or
did not have an impairment at Wave One and Wave Two but were living in the same household as an adult who had at least one impairment at Wave One, or in the same household as an adult who was identified as onset-acquired from the screener exercise.
For more information on the development of the use of the ‘control’ group, see Annex 1 (136.9 Kb Pdf) which provides a summary of the development of the Wave Two weights.
Classification of individuals for Wave Two longitudinal analysis
Diagram 1 shows how adults have been classified for the longitudinal analysis. The classification takes into account impairment status at both Wave One and Wave Two. Figure 1 also illustrates how adults who did not report any impairment at either Wave One or Wave Two flow through the survey.
The following four groups are featured in the longitudinal analyses of this report:
adults who had at least one impairment at Wave One and at Wave Two are ‘adults with impairment at both waves’,
adults who had at least one impairment at Wave One but no impairments at Wave Two are ‘offset adults’,
adults who did not have any impairment at Wave One but had at least one impairment at Wave Two are ‘onset-acquired adults’, and
adults who did not have any impairment at Wave One or at Wave Two are ‘adults without impairment at both waves’.
Diagram 1.1, Classification of adults for LOS wave two longitudinal analysis
Notes for brief outline of the LOS methodology
Outline of chapters
The main focus of this report is to explore how adults are restricted in taking part in different areas of their life and the specific barriers they encounter. The data analysed for the report came from respondents who were interviewed in both Wave One and Wave Two of the LOS and focuses on the longitudinal aspect of the data. Chapter 2 explores whether adults1 are restricted in each of the eight LOS life areas. Chapters 3 to 5 describe specific barriers reported for the life areas of work, education and training, and transport for adults of working age, respectively2. Change in adults’ experience of participation restriction and barriers between Wave One and Wave Two is considered. Finally, Chapter 6 gives a summary of the general findings of the report.
As identified above, analysis of barriers focuses on three of the eight LOS life areas- work, education and training, and transport. The topics were chosen to focus on the policy priority to understand more about barriers adults experience to work, and topics related to work. Therefore the analysis in Chapters 3 to 5 focuses on adults of working age (aged 16 to 64).
The data have been weighted to provide estimates for the general population (see Annex 1 (136.9 Kb Pdf) which provides a summary of the development of the Wave Two weights).
Longitudinal analysis groups
Throughout the report comparisons are made between the four groups of adults as described in section 1.2 - adults with impairment at both waves, offset adults, onset-acquired adults, and adults without impairment at both waves. The four groups reflect the diversity of impairment status, in that impairment status may be stable, or may change over time. A person may have impairments at both waves or no impairment at both waves, or they may no longer have impairments or they may acquire an impairment at Wave Two.
Participation restriction and barriers
An adult has a participation restriction in a life area if they experience at least one barrier in that area. For example, in education and training, respondents were asked if they had access to all the learning opportunities that they wanted3. If they answered ‘no’, they were then asked to specify the barrier(s) experienced. For education and training, these included:
‘financial reasons (lack of money/can’t afford to)’,
‘too busy/not enough time’
‘lack of information’
‘no learning opportunities available’
'a health condition, illness or impairment’
For another life area, the barriers reported may be different. For example, ‘lack of job opportunities’ is a barrier applicable to work, whereas ‘difficulty getting to stop or station’ is a barrier applicable to the use of public transport such as local buses and long distance trains.
The barriers reported by adults may change over time. For each life area it is possible to see if a particular barrier was:
reported at both waves
reported at Wave One only
reported at Wave Two only
not reported at either wave
The analysis of barriers in Chapters 3 to 5 includes working age adults, who experienced a participation restriction to the specific life area being analysed at any point in the survey. For these adults the types of barriers that were reported at both waves or at either wave (groups i, ii, and iii above) will be examined by group.
Analysis of barriers in Chapters 3 to 5 is presented in tables showing the top four barriers that were reported by each group; broken down by whether the specific barriers were reported at both waves or at one wave of the survey4. The analysis has been approached in this way in order to explore the types of barriers that are reported at both waves (i.e. those that are persistent), compared to those that are reported at one wave only (i.e. those that are transient).
The top four barriers form the focus of our analysis given the small number of respondents selecting other barrier types. The full range of barrier types reported in the life areas of work, education and training, and transport, can be seen in the reference tables provided.
The commentary provides descriptive comparisons of the top four barriers, drawing high level conclusions about the relationships between impairment status, participation restriction, and how this changes over time. Direct comparisons are not made of the percentage of adults experiencing specific types of barriers. This approach was taken because of the small sample sizes that result when splitting the dataset into the subsets as described above (i.e. longitudinal analysis group, and barriers experienced across waves of the survey within the three topic areas).
In the life area of work, LOS respondents were also asked to report ‘enablers’ - measures that helped them at work, or would help them to be able to work. Chapter 3 includes the types of enablers that were reported by employed and economically inactive adults for each of the longitudinal analysis groups. Due to insufficient sample size, it is not possible to analyse adults who were unemployed at both waves5.
Within the LOS questionnaire employed adults were asked to select from a list of enablers, anything that helped them at work. Enablers included ‘Modified hours or days or reduced hours’, ‘modified duties’, and ‘equipment to help with a health condition or disability’6. From the same list, economically inactive adults were asked if they needed any of the enablers to be able to work.
Notes for Wave Two Part II analyses
All adults aged 16 and over are included in the analysis of participation restriction
Adults aged 16 to 64 are included in the barriers analysis
LOS questionnaire questions 126 and 127
The rankings are calculated based on the percentage of adults who reported each particular barrier at both waves, at Wave One only, or at Wave Two only, out of those adults from that particular group who had a participation restriction at either or both waves. For barrier tables 'other reasons' and suppressed values have been excluded from the ranking
Chapter 2 provides some details on the effect of change in economic activity status on barriers reported
The results from the longitudinal analysis of the LOS will be used to inform a new understanding of the dynamic nature of the disabled population and of the barriers faced by people with impairment. As identified in external research, it is important to understand more about the dynamic nature of disability and the barriers people with impairments face1, this will be used to inform policy development in particular on the support people need during onset of impairment.
As well as looking at barriers, wave 3 of the LOS will also collect information on the key enablers to removing barriers. This will inform the development of the approach the Government will take in helping disabled people to fulfil their potential and have the opportunity to play a full role in society.
The LOS Wave Three questionnaire will include questions designed to collect information about onset and offset of impairment. In particular additional questions will be asked to provide understanding of any enablers that may have resulted in the removal of barriers to participation in particular life areas. It is hoped the additional information will also allow further understanding of survey error, in particular the extent of mis-reporting of changes in experience of participation restriction.
Notes for why is it important to study barriers to participation to understand disability?Back to table of contents
Units, presentation and accuracy
Detailed definitions of the terms and categories used in this report are provided in the Glossary at the end of the report.
All estimates presented in the tables and charts have been analysed using longitudinal weights so that they have been adjusted for non-response, differential sampling probabilities of selection at Wave One, and loss to follow-up at Wave Two (more information on weighting can be found in Annex 1 (136.9 Kb Pdf)).
Percentages reported throughout the document have been calculated using population estimates rounded to integers. When calculating percentages, the values of residual categories such as ‘no answer’ or ‘don’t know’ have been excluded from the denominator.
Sample attrition, household and individual response rates
The response rate for LOS Wave Two can be calculated at both household and individual level. The LOS Wave Two achieved a household level response rate of 77%. In this case responding households were those in which information was collected in person or by proxy for all adults. The survey achieved an individual response rate of 74%, among adults who were eligible for a face-to-face interview.
For longitudinal surveys, the sample is subject to attrition moving from one wave to the next. For the LOS, a subset of the original sample at Wave One were not contactable, did not respond, or refused further participation at Wave Two. More information on sample attrition and the household and individual response rates can be found in Annex 3 of the Part I report (136.9 Kb Pdf).
In Chapter 2, unless otherwise stated, changes and differences mentioned in the text have been found to be statistically significant at the 95% confidence level.
The analysis of the types of barriers adults experienced (presented in Chapters 3 to 5) are presented as a qualitative description comparing the top four barriers. Given direct comparisons of the percentage of adults experiencing specific types of barriers are not made, no significance testing has been carried out on the findings reported in these chapters.Back to table of contents
Specific strengths of using the LOS
LOS is a longitudinal survey that has been designed to follow respondents over time to provide an insight and understanding into the transient nature of impairment. A key component of the survey design is the ability to compare the experience of barriers to participation between people with impairment and those without impairment over time to assess the equality in access in different life areas. The formation, at Wave Two, of a control group from within the respondents who did not have any impairments at Wave One, will allow experiences to be compared between the two groups over time
As the first longitudinal survey of its kind, the data collected provides a unique and rich source of data for use by analysts. Both to understanding more about the transitions into and out of impairment, as well as different types and severity of impairment experienced by adults in Great Britain
Survey design. The LOS uses an unclustered sample designed to produce efficient estimates for the sample size and Great Britain. The unclustered sample allows greater precision to be achieved in LOS outputs because it helps to make the sample more representative of all groups in society1
The size of the Wave One sample was sufficient to accommodate for attrition over time. As a result, at Wave Two, the sample remains of a sufficient size to allow for comparisons and analysis to be conducted among subgroups of the sample
Specific weaknesses of using the LOS
Potential under or over reporting of impairment. The LOS collects self-reported impairment data which is dependent upon the respondent’s perception of the limitations and severity of the impairment at the time of the interview. A self-reporting measure of this kind is prone to both over and under reporting as the perception of the existence and effect of impairment is dependent upon each respondent’s own personal opinion on the day they are interviewed
One consequence of this is that respondent’s perception of the impairment may differ over time causing transitions to be recorded that may or may not be real. For example, the LOS definition of impairment is dependent upon the respondent reporting more than ‘mild’ difficulty. If at Wave One they report ‘moderate’ difficulty they will be classed as having an impairment according to the LOS definition. However, if at Wave Two we assume that there has been no change in the impairment and the respondent reports ‘mild’ difficulty, LOS will no longer class them as having an impairment. Using this example, the respondent will be treated as having offset from impairment at Wave Two
Cross-sectional weights are not available on the LOS Wave Two dataset and therefore estimates of impairment prevalence cannot be calculated. Overall estimates of disability prevalence are available from the Family Resources Survey2
The LOS is a sample survey and so is subject to weaknesses which also exist for other surveys, including:
Non-sampling error. Estimates from all sample surveys, including those derived from the LOS data, will contain a degree of uncertainty due to non-sampling and sampling error. Non-sampling error generally arises from errors in the collection, measurement and processing of the data3. To minimise non-sampling error the LOS questionnaire was administered using computer assisted interviewing (CAI), which ensured that the questionnaire routing was followed correctly during the interview and inconsistencies and potential collection errors were able to be queried, and where appropriate, corrected during the interview4. Again, to minimise non-sampling error, as a result of errors arising from data collection, all ONS interviewers received both generic interviewer training and specific LOS training prior to working on the LOS. The LOS Wave One Technical Report provides further information about the data collection and processing of the data5
Sampling error. This relates to the fact that the sample chosen is only one of a large number of samples which could have been chosen. It follows then that any estimate derived from the sample is only one of a large number of estimates which could have been made. For users of survey data, the precision of the estimate is of interest, that is, how much the estimate would vary when different samples are drawn6. In general, the larger the sample size from which the estimate is derived, the more precise, or robust, is the estimate
Non-response and missing information. The information from a household which co-operates in the survey may be incomplete. This can be due to one of the following reasons: i) a partial refusal (e.g. to income); ii) because information was collected by proxy, therefore certain questions were omitted from the interview; or iii) a particular item was missed because of a lack of understanding or an error
Survey coverage. The LOS Wave One sample was designed to cover private households in Great Britain. Therefore individuals in care or retirement homes, for example, will not be included. This means that figures relating to the severely disabled and the most elderly individuals may not be representative of the Great Britain population, as many will have moved into homes where they can receive more frequent help
The survey at Wave Two follows individuals, and their households, and remains a private household survey. This means that any respondents who have moved into institutions (care or retirement homes, prison, etc) between Waves One and Two were not followed at Wave Two and were recorded as not eligible to participate in the survey
The LOS Wave Two set sample comprised only of households of individuals who had participated at Wave One and did not include any new households. This approach does not allow the sample to be refreshed to include any new population sub-groups that may have entered the country since the sample was drawn for Wave One. However, any adult or child who had entered a LOS household since the Wave One interview are included as new survey entrants at Wave Two
Survey bias. Although work has been undertaken to try to ensure that the figures that have been collected are valid and that adjustments are made for attrition, survey bias may still remain. This may be partly due to misreporting of certain data items and sampling error, but also may reflect non-response biases not controlled for in the weighting factors. Efforts are continually being made to minimise these problems, for example through greater reliance on documentary evidence at the interview and maintaining response rates
Notes for Strengths and weaknesses
LOS Wave One Technical Report 2009/11 p.5 Sampling Methodology
Information on non-sampling errors (p.200)
The precision of the estimate can be gauged by its confidence interval – the range of values within which the population parameter is estimated to lie. The narrower the interval, the more precise is the estimate.
A summary of this report is available in alternative formats such as Large Print, Braille, Audio or Easy Read. The Easy Read version (0.99 Mb Pdf) is available via the ONS website. Large Print and Braille copies are available from the ONS LOS team. The Audio version is available via the DWP website1. Contact the LOS team by email LOS@ons.gov.uk or by telephoning +44 (0) 1633 455296.
The LOS Wave Two datasets will be made publicly available in 2014, via the UK Data Archive2.
Notes for availability of detailed and unpublished dataBack to table of contents
Helen Tam Joanna Bulman Claire Vafidis Daniel Shiloh
Life Opportunities Survey Team
Buffy Matthews Kimberly Lloyd Field Team and Interviewers
Karl Ashworth Andy Fallows Sangeetha Gallagher
Colleagues at the Department for Work and Pensions, in particular:
Joanna Littlechild Riaz Ali Roger MorganBack to table of contents
Row, column or table percentages may not sum to 100 due to rounding
All reported sample sizes are rounded independently to the nearest ten. For this reason, sample sizes for totals may not equal the sum of sample sizes for components
Symbols used in tables
.. Figure suppressed due to small cell count.
n/a Not applicable.
0 Less than 0.5%, including none.
 Figures should be used with extra caution because they are based on fewer than 30 reporting individuals.Back to table of contents