• Relationship to the Conners’ Adult ADHD Rating Scales (CAARS)
• Relationship to the Comprehensive Executive Function Inventory Adult (CEFI Adult)
• Relationship to the Weiss Functional Impairment Rating Scales Self-Report (WFIRS-S)

Relationship to the Conners’ Adult ADHD Rating Scales (CAARS)

The CAARS 2 is a revision of the original CAARS™ (Conners, Erhardt, & Sparrow, 1999), a measure of symptoms and features related to ADHD for adults. To provide evidence of the validity of the CAARS 2 scores based on their relation to scores from a similar measure of the constructs, individuals and observers were asked to complete the CAARS 2 and the CAARS. The two instruments are inherently related due to the item and construct overlap; however, many historic items in the CAARS 2 were revised and new items were added (see chapter 6, Development, for detailed information about updated content from the CAARS to CAARS 2). Accordingly, it was expected that the CAARS 2 and CAARS would be strongly related, as the items and scales are similar but distinct.

To test this hypothesis, adults diagnosed with ADHD (N = 103) were asked to complete the CAARS 2 and the original full-length CAARS Self-Report forms, and then they were asked to recruit someone who knew them well enough to complete the CAARS 2 and CAARS Observer forms (N = 63). Detailed descriptions of individuals being rated, as well as the Observer raters, are provided in appendix J. Raters completed the CAARS and CAARS 2 within the span of one month; the interval between administrations of the two tests ranged from completion on the same day to 26 days later for Self-Report and up to 31 days later for the Observer form.

Scales with conceptually similar content were paired together for this study, and these paired scales were expected to be strongly related. Correlations between scales with similar content, as well as descriptive statistics, are presented in Tables 9.6a and 9.6b. Correlation coefficients were corrected for range variation (i.e., due to sampling variability, the selected sample’s SD deviates from the Normative Sample’s SD; Stauffer & Mendoza, 2001).

As expected, for Self-Report and Observer, corrected correlations revealed statistically significant, strong-to-very strong relationships between the corresponding scales (Self-Report corrected r = .65 to .82, Observer corrected r = .68 to .90; all p < .001). Overall, the high degree of association between the two measures provides evidence for the convergent validity of the CAARS 2, as it aligns closely with and appears to measure the same construct as an established, validated measure of ADHD in adults.

Relationship to the Comprehensive Executive Function Inventory Adult (CEFI Adult)

For evidence that the CAARS 2 accurately captures aspects of executive functioning, individuals with ADHD and observers were asked to complete both the CAARS 2 and the Comprehensive Executive Function Inventory Adult (CEFI Adult™; Naglieri & Goldstein, 2017). The CEFI Adult is an 80-item measure of behaviors associated with executive function for individuals aged 18 years and older, with higher standard scores reflecting greater ability or functioning (M = 100, SD = 15; note that CEFI scales are scored in the opposite direction of the CAARS 2 T-scores such that higher scores indicate greater ability, rather than a deficit). The CEFI Adult is composed of items related to Attention, Emotion Regulation, Flexibility, Inhibitory Control, Initiation, Organization, Planning, Self-Monitoring, and Working Memory, as well as a total score that measures executive functioning more broadly (Full Scale score). Executive function deficits are a core feature of ADHD, and scores on the CAARS 2 were expected to show significant negative (due to the opposing scoring directions) correlations with corresponding content areas measured by the CEFI Adult.

Raters (N = 107 for Self-Report and N = 56 for Observer) completed the CAARS 2 and were then asked to complete the CEFI Adult within four weeks. Details about the individual being rated as well as the raters can be found in appendix J.

Scores on the CAARS 2 and CEFI Adult were compared via correlational analyses, and corrections were applied to the correlations to account for range variation (i.e., due to sampling variability, the selected sample’s standard deviation deviates from the Normative Sample’s standard deviation; Sackett et al., 2000). These results, along with descriptive statistics for each scale, can be found in Tables 9.7a and 9.7b.

For both forms, corrected correlations revealed strong to very strong relationships (all p < .001) between the corresponding scales of the two tests. The CAARS 2 Total ADHD Symptoms scale was strongly related to the CEFI Adult Full Scale (Self-Report corrected r = -.68; Observer corrected r = -.70). Scores on the CEFI Adult scales with content similar to content on the CAARS 2 Inattention/Executive Dysfunction scale were observed to be strongly to very strongly correlated (Self-Report corrected r = -.71 to -.87; Observer corrected r = -.61 to -.79). Additionally, strong correlations were found between the CAARS 2 Impulsivity and CEFI Adult Inhibitory Control scale scores (Self-Report corrected r = -.67; Observer corrected r = -.75), and between the CAARS 2 Emotional Dysregulation and the CEFI Adult Emotion Regulation scale scores (Self-Report corrected r = -.68; Observer corrected r = -.64). These results provide evidence for the valid measurement of these concepts on the CAARS 2 by demonstrating hypothesized and significant relationships to a measure of similar constructs from an established tool.

Relationship to the Weiss Functional Impairment Rating Scale Self-Report (WFIRS-S)

The CAARS 2 contains items designed to capture (a) the frequency and severity of several specific types of functional impairment commonly exhibited by individuals diagnosed with ADHD, and (b) the overall impact of ADHD-related behaviors on the life of the individual being rated (see chapter 1, Introduction). The association between scores on the CAARS 2 Impairment & Functional Outcome Items and scores from the established Weiss Functional Impairment Rating Scale (WFIRS™) was explored to consider how well the CAARS 2 Impairment & Functional Outcome Items converge on the construct of functional impairment. The relation between these two measures was important to explore given the relevance of both tools in the assessment of ADHD populations (Weiss et al., 2018). Moreover, the CAARS 2 Self-Report Impairment & Functional Outcome Items explore similar functional domains as WFIRS, namely the Family, Work, and Social domains.

To establish evidence for convergent validity of the CAARS 2 Self-Report Impairment & Functional Outcome Items, data on the WFIRS Self-Report were collected alongside the CAARS 2. A sample from the CAARS 2 Self-Report containing only ADHD-diagnosed individuals (N = 255) was used in this study (see appendix J for a detailed description of the sample). Specifically, bivariate correlations were used to evaluate the extent to which item scores in the CAARS 2 Self-Report Impairment & Functional Outcomes Items associated with T-scores in the corresponding WFIRS Self-Report domains.

Results for this study are presented in Table 9.8. Correlations revealed statistically significant, moderate relationships (r = .40 to .56, p < .001) with the corresponding CAARS 2 Self-Report Impairment & Functional Outcome Items. The WFIRS Self-Report Overall Score was weakly correlated with the CAARS 2 Self-Report item “Has a harder time with things than others do” (r = .28, p < .001), as the latter may connect to feelings of self-esteem or self-worth more so than functional impairment, as captured by the WFIRS Overall Score. Overall, there is evidence to demonstrate that the WFIRS Self-Report measures similar constructs as the CAARS 2 Self-Report Impairment & Functional Outcome Items, and the WFIRS Self-Report domains converge on the intended construct of functional impairment.