Participation involves functioning in domestic, social, and occupational settings4
and is a key indicator of quality of life. Participation is an important outcome across diverse disease/illness categories.1–3
Despite its importance, few psychometrically sound instruments measure this construct. One of the most commonly used instruments is the CIQ. Although originally developed for use in TBI, it has been used increasingly in research on non-TBI populations.12–16
Nevertheless, we could not find any studies that comprehensively examined its psychometric properties in these groups. The current study addresses this gap. The overall results provide general psychometric support for the CIQ for clinical and research use in this population. However, these results did not exactly replicate those from which the original scoring system was derived. The implications of these discrepancies are discussed throughout the Discussion section.
Our comprehensive analytic approach included exploratory and confirmatory analyses. Because factor analytic results can differ substantially based on parameter specifications,56
using just 1 approach can yield erroneous conclusions. Our approach minimized this possibility and allowed us to determine if consistent patterns emerged across analyses. The results suggest the original scoring system7
may require modification to optimize use of the CIQ in adults with physical disabilities.
Although we largely replicated the item-factor loadings of the original scoring of Home Integration, item 6 (personal finances) loaded on Home Integration in our analyses but is originally scored on Social Integration. Item 6 seems more similar to other home-based activities; therefore, we consider it a reasonable scoring modification to include it on Home Integration when using the CIQ in physically disabled adults. Interestingly, this echoes the suggestion of Sander et al11
based on results of a large TBI study. Also, in keeping with the revised scoring system recommended by Sander,11
we found that dropping item 4 (childcare), which is originally scored on Home Integration, improved the CIQ’s psychometrics. Because many physically disabled respondents may not have children, this too seems a reasonable scoring modification. However, we recommend making this modification on a post hoc basis, as opposed to deleting the item altogether, so as to not lose potentially meaningful information from respondents who do have children.
Several item-factor cross-loadings were also necessary to achieve a well-fitting model in our data. Item 7 (shopping frequency) is originally scored on Social Integration but cross-loaded on Home Integration and Social Integration. The magnitude of these loadings was similar, suggesting this item equally taps a unique component common to both domains. These results are consistent with those from another study in TBI.11
One can certainly conceive shopping as a home-related activity; indeed, another shopping item (item 1) is scored on Home Integration. Conversely, shopping outside the home is inherently social. Moreover, many individuals with a physical disability require assistance to complete shopping-related activities. Although others11
have suggested dropping this item from the CIQ, we suggest retaining it for additional research among physically disabled adults. Our more cautious recommendation is because, unlike TBI, few studies have examined the factor structure of the CIQ in adults with physical disabilities. Thus, we consider it prudent to recommend additional research before making major changes to the CIQ’s item composition.
Item 12 (travel frequency) had equivalent loadings on Social Integration and Productive Activities but is typically scored only on Productive Activities. Physically disabled adults often require assistance from others to travel, thus making this a social activity regardless of travel purpose. However, because travel often relates to academic and/or vocational activities, it also makes sense that item 12 loads on Productive Activities. Sander et al11
found it loaded exclusively on Social Integration, which is reflected in their revised scoring. At this point, it is unclear how to score this item for adults with a physical disability. Because of a slightly stronger loading, we scored it on Social Integration for subsequent analyses. However, further research is needed to determine an optimal long-term solution in physically disabled groups.
Finally, job/school loaded on Social Integration and Productive Activities in our analyses, but is typically scored only on Productive Activities. We analyzed the composite variable, whereas others (eg, Sander11
) have considered separately the 3 individual items that comprise job/school. Although these analytic differences could produce discrepant findings, our results are in line with previous research highlighting concerns about Productive Activities. In fact, this factor has consistently been less robust than Home Integration and Social Integration in studies across and within diagnostic groups.11,17–19,61
As such, we agree with others11
that additional items may be needed to improve measurement of this domain.
Our results also help establish the concurrent validity of the CIQ (original and revised scoring) among the current heterogeneous sample, indicating its usefulness in non-TBI groups. With the exception of Home Integration, the Total scale and subscales demonstrated significant and positive associations with 2 well-established measures of general and mental health. Importantly, these associations, although significant, were weak to moderate in magnitude,59
indicating that the CIQ measures a related but distinct construct. Two recent studies in SCI14,62
also support the CIQ’s concurrent validity in non-TBI samples. Although neither study involved an extensive psychometric analysis, they do suggest the CIQ is a useful measure of participation in this diagnostic group.
Our reliability analyses also raise concerns about the original scoring system in individuals with a physical disability. The revised scoring based on our findings proved superior in this respect; internal consistency coefficients for Home Integration and Social Integration were .74 and .63, respectively (α
for Productive Activities could not be calculated because it consisted of a single item). Interestingly, these findings concerning the original scoring are generally consistent with previous research in TBI samples.9
The CIQ is not the only measure of participation for individuals with disabilities.63
However, it is widely used in research and practice, likely due to its face validity, correspondence with the WHO4
concept of handicap, brevity, and ease of administration. Despite these positive features, concerns have been raised about the CIQ. Dijkers’18
critiques regarding scope, content, and norms seem particularly relevant to the current study. In terms of content, as noted in the Introduction and Methods sections, the CIQ was developed to assess 3 domains of handicap; whereas the most recent WHO conceptualization includes 9 domains.4
The CIQ does not assess all of these domains; for example, it does not contain content on learning/applying knowledge or communication. Additional research can determine whether and how to improve existing measures of participation to maximize their research and clinical applications.
Several study limitations should be considered. First, the sample was largely white and well-educated, which may limit generalizability of the findings. Second, we sampled from 4 disability groups, which represents only a subset of disability diagnoses. Third, because we did not formally screen for cognitive impairment, we cannot be certain these participants comprised a “pure” physical disability sample. Fourth, the CIQ’s psychometric properties might differ across disability diagnoses; for example, functioning at home may differ whether one has MS, SCI, or another disability. Although we found, with the exception of Home Integration, the disability groups did not differ on the CIQ, this is an insufficient level of analysis to determine whether the CIQ has differential performance across groups. Unfortunately, we did not have sufficient sample sizes to more thoroughly examine the CIQ’s psychometrics separately for each group. Finally, conclusions about concurrent validity would have been stronger if nonself-report assessments, such as behavioral measures and spouse/partner report, were included in these analyses.