Mindfulness is defined as bringing one’s attention to the moment-to-moment experience in a non-judgmental and accepting way (Kabat-Zinn
1990) and has been receiving increasing interest within clinical and non-clinical settings. During the last three decades, several mindfulness-based interventions, such as mindfulness-based stress reduction (MBSR) (Kabat-Zinn
1990) and mindfulness-based cognitive therapy (MBCT) (Segal et al.
2013) have been developed and their efficacy has been established in a large number of studies (Khoury et al.
2013; Kuyken et al.
2016).
Consequently, the assessment of mindfulness has increasingly received attention and several self-reporting questionnaires have been developed. These include the Mindfulness Attention Awareness Scale (Brown and Ryan
2003), the Freiburg Mindfulness Inventory (Walach et al.
2006), the Kentucky Inventory of Mindfulness Skills (Baer et al.
2004), the Southampton Mindfulness Questionnaire (Chadwick et al.
2008), the Cognitive and Affective Mindfulness Scale (Feldman et al.
2007), the Five Facet Mindfulness Questionnaire (FFMQ; Baer et al.
2006), the Philadelphia Mindfulness Scale (Cardaciotto et al.
2008), and the Toronto Mindfulness Scale (Lau et al.
2006). Bergomi et al. (
2013b) examined these eight validated mindfulness questionnaires in detail and identified nine distinguishable aspects of mindfulness skills covered in these instruments. These aspects include (1) observing, attending to experiences; (2) acting with awareness; (3) non-judgment, acceptance of experiences; (4) self-acceptance; (5) willingness and readiness to expose oneself to experiences, non-avoidance; (6) nonreactivity to experience; (7) non-identification with own experiences; (8) insightful understanding; and (9) labeling, describing. Bergomi et al. (
2013a) concluded that none of the available instruments covered all aspects, as each questionnaire was based on a slightly different definition of mindfulness and emphasized different aspects of mindfulness skills. In addition, several studies imply that the comprehension of mindfulness scales is influenced by meditation experience (Baer et al.
2006; Baer et al.
2008; Curtiss and Klemanski
2014). In a recent study, Gu et al. (
2016) examined the factor structure of the FFMQ in participants taking part in MBCT. Based on the results, they propose to exclude the subscale “observing” when comparing scores before and after mindfulness interventions, as scores are likely to be inflated by a better understanding of the construct. Taken together, none of the available mindfulness questionnaires covers the whole range of the mindfulness construct and is equally applicable for samples varying in meditation experience.
Taking these limitations into account, Bergomi and colleagues (Bergomi et al.
2013b; Bergomi et al.
2014) developed the Comprehensive Inventory of Mindfulness Experiences (CHIME). The CHIME is based on a thorough literature review and comparing of the existing mindfulness questionnaires. The CHIME not only covers a broad range of the mindfulness aspects but the developers also paid special attention to make the scale more comprehensible for community samples irrespective of meditation experience. Psychometric properties of the CHIME were evaluated as good in samples consisting of community members and participants of MBSR (Bergomi et al.
2014). Importantly, a recent study investigated whether scores of the CHIME are dependent on a better understanding or response shift due to a mindfulness intervention. The results showed that scores of the CHIME were only minimally influenced by a better or changed understanding of the concept of mindfulness (Krägeloh et al.
2018). Therefore, the CHIME has potential to be a useful instrument in mindfulness research. However, as the CHIME was validated in German, it is not yet available in Dutch. Furthermore, even though the sensitivity to change of the CHIME has already been demonstrated in a non-clinical sample of MBSR participants (Bergomi et al.
2014), it has not yet been tested in a clinical sample receiving MBCT within a mental health care institution.
The purpose of this study was to translate the CHIME questionnaire into Dutch and to evaluate its psychometric properties. The factor structure, internal consistency, and validity of the Dutch CHIME were investigated in a mixed sample consisting of one clinical and two non-clinical samples. Furthermore, the sensitivity to change of the CHIME before and after a mindfulness intervention (MBCT/MBSR) was evaluated in the clinical and one of the non-clinical samples. The second aim of this study was to develop a short form of the CHIME, with similar content validity and psychometric properties to the full version. A shorter version of the CHIME is particularly relevant for research settings where time constraints make the use of the long form less feasible or the questionnaire is administered on multiple occasions.
Method
Participants
A total of 481 persons participated in the current study, consisting of three different samples: one clinical sample, and two non-clinical samples. All participants gave informed consent to voluntarily participate and anonymity was guaranteed. Demographic characteristics are presented in Table
1.
Table 1
Demographic characteristics
N
| 232 | 127 | 122 |
Mindfulness intervention | MBCT | MBSR | MBCT/MBSR |
Age, M (SD), in years | 46.9 (13.45) | 42.1 (12.27) | 49.0 (11.4) |
18–25 | 5.6% | 7.9% | 2.5% |
26–35 | 17.2% | 29.9% | 13.1% |
36–45 | 25.9% | 19.7% | 21.3% |
46–55 | 20.3% | 24.4% | 32.0% |
56–65 | 22.0% | 18.1% | 25.4% |
> 65 | 9.1% | 0% | 5.7% |
Gender |
Male | 29.7% | 19.7% | 19.7% |
Female | 70.3% | 80.3% | 80.3% |
The first sample (clinical sample) consisted of 232 patients who participated in a MBCT course for patients with recurrent depressive disorder provided at the department of psychiatry at the Radboud University Medical Center, Nijmegen, The Netherlands. All trainers teaching MBCT at the Radboud University Medical Center were experienced in working with depressed patients and completed a 2-year mindfulness teacher training. The second sample (non-clinical sample 1) consisted of 127 persons participating in a MBSR course for the general public at the Radboud University Medical Center, Nijmegen, The Netherlands. The third sample (non-clinical sample 2) consisted of 122 participants who had followed an MBCT/MBSR course in Flanders in the past. This sample was recruited using snowball sampling via e-mail. An e-mail with detailed information was sent to mindfulness trainers in Flanders, requesting circulation of this invitational e-mail to former MBCT/MBSR attendees.
Procedures
The study was divided in three stages. First, the German version of the CHIME was translated into Dutch according to a standardized procedure (Guillemin et al.
1993). Second, the model fit, validity, and sensitivity to change of the translated version were tested. Third, a short form of the CHIME was developed and its psychometric properties were evaluated.
Intervention
The MBCT and MBSR programs were based on the original programs by Kabat-Zinn (
1990) and Segal et al. (
2013) and consisted of eight weekly 2.5-h group sessions, one silent day, and daily 45-min home practice. Mindfulness exercises, such as body scan, gentle yoga, sitting, and walking meditation, were practiced. Participants received teachings on stress and/or depression and were invited to share their experiences. In total, 96.5% of the whole sample attended a MBCT/MBSR course provided by a certified mindfulness trainer, of the remaining 3.5%, no information regarding the trainer was available.
Data Analyses
The data of all three samples were used to investigate the factor structure of the CHIME. For descriptive statistics, internal consistency, sensitivity to change analyses, and correlations, SPSS (version 22) was used, whereas SPSS AMOS was used to perform confirmatory factor analyses (CFAs) and to test measurement invariance. To compute a corrected correlation to evaluate the CHIME-SF, Levy’s formula (Levy
1967) was used as incorporated in the Shortform Version 1.1 software developed by Barrett (
2005).
Results
Factor Structure of the CHIME
Table
2 presents the fit indices for the CFA model tested for the CHIME. The single-factor model of the CHIME showed a poor fit to the data, indicating that all items of the CHIME as a group do not measure a unidimensional construct of mindfulness. Both the hierarchical and correlational 8-factor models showed a satisfactory fit; however, in line with the original validation study (Bergomi et al.
2014), the correlational model performed slightly better than the hierarchical. However, one item (item 3) had a low factor loading (.29), indicating that this item contributed minimally to the subscale “insight,” see Table
S1 in the Appendix. In accordance with the original validation study, we also examined correlational and hierarchical 7 + 2-factor models, these showed similar model fits to the 8-factor models.
Table 2
CFA fit indices for the models tested for the CHIME and the CHIME-SF (N = 481)
CHIME |
1 factor | 4170.07 | 629 | 6.63 | 0.61 | 0.108 (0.105, 0.111) | 0.10 |
8-factor correlated | 1534.90 | 601 | 2.55 | 0.90 | 0.057 (0.053, 0.060) | 0.06 |
8-factor hierarchical | 1736.10 | 621 | 2.80 | 0.88 | 0.061 (0.058, 0.065) | 0.08 |
7 + 2-factor correlated | 1543.17 | 606 | 2.63 | 0.90 | 0.057 (0.053, 0.060) | 0.06 |
7 + 2-factor hierarchical | 1633.25 | 620 | 2.55 | 0.89 | 0.058 (0.055, 0.062) | 0.07 |
CHIME-SF |
1 factor | 2294.35 | 252 | 9.11 | 0.62 | 0.130 (0.125, 0.135) | 0.10 |
8-factor correlated | 486.13 | 224 | 2.17 | 0.95 | 0.049 (0.043, 0.055) | 0.05 |
8-factor hierarchical | 632.22 | 244 | 2.59 | 0.93 | 0.058 (0.052, 0.063) | 0.07 |
These findings show that the CHIME measures eight distinct but related aspects of mindfulness skills, of which two factors (inner awareness and outer awareness) can be combined as an overall factor measuring awareness. The eight distinct factors can be considered as facets of an overall mindfulness factor.
To test whether the factor structure of the CHIME is stable across clinical and non-clinical groups, configural and metric invariance was investigated. First, the model fit of the correlational 8-factor model was tested separately for the clinical sample and non-clinical group. In both samples, the model had a satisfactory fit (clinical sample: χ2 = 1037.90, df = 601, χ2/df = 1.73, CFI = 0.89, RMSEA = 0.056 [90% CI 0.05, 0.062], SRMR = 0.07; non-clinical sample: χ2 = 1346.54, df = 601, χ2/df = 2.24, CFI = 0.84, RMSEA = 0.071 [90% CI 0.066, 0.076], SRMR = 0.08). When testing the correlational 8-factor model in a multiple group analysis, a satisfactory model fit was found: χ2 = 2384.44, df = 1202, χ2/df = 1.98, CFI = 0.86, RMSEA = 0.045 [90% CI 0.043, 0.048]. This shows that the global factor structure is the same for the clinical and non-clinical group (configural invariance). Next, we constrained the factor loadings to be the same across both groups (metric invariance), which revealed a satisfactory model fit, χ2 = 2416.93, df = 1231, χ2/df = 1.96, CFI = 0.861, RMSEA = 0.045 [90% CI 0.042, 0.047]. Model comparisons of the configural model and metric model indicate noninvariance (∆CFI < 0.001, ∆RMSEA < 0.001). This indicates that in the correlational 8-factor model, each item contributes to the latent constructs to a similar degree across the clinical and non-clinical group.
Internal Consistency and Intercorrelations of the Subscales
Correlations between the eight subscales of the CHIME are displayed in Table
3. All subscales were significantly related with Pearson correlations ranging from .17 to .69, indicating that the subscales measure related but distinct facets of mindfulness skills. The reliability of the subscales measured with Cronbach’s alpha and highly acceptable, ranging from
α = .71 for acting with awareness to
α = .89 for acceptance (see Table
3).
Table 3
Internal consistency and correlations of subscales of the CHIME
Inner awareness | .78 | – | | | | | | |
Outer awareness | .88 | .59** | | | | | | |
Acting with awareness | .71 | .21** | .26** | | | | | |
Acceptance | .89 | .33** | .34** | .44** | | | | |
Decentering/nonreactivity | .88 | .42** | .40** | .45** | .69** | | | |
Openness | .72 | .23** | .19** | .31** | .38** | .36** | | |
Relativity | .75 | .40** | .31** | .17** | .48** | .57** | .22** | |
Insight | .79 | .53** | .48** | .27** | .55** | .64** | .24** | .60** |
Convergent and Discriminant Validity of the CHIME
Pearson correlations between the CHIME and convergent and discriminant measures are displayed in Table
4. In general, the correlations met the predictions about their direction and magnitude. However, the correlations were stronger in the clinical sample compared with the non-clinical sample. As expected, the subscale “decentering/nonreactivity” was strongly, positively correlated with the subscale “reacting” of the FFMQ (clinical sample
r = .77; non-clinical sample 1
r = .72). The subscale “acting with awareness” was moderately, positively correlated with the subscale “acting with awareness” of the FFMQ (clinical sample
r = .49; non-clinical sample 1
r = .38). In the clinical sample, all subscales of the CHIME showed significant positive correlations with a measure of self-compassion (SCS). All subscales except from “inner awareness” showed significant negative correlations with measures of depression (BDI-II) and worry (PSWQ). That the subscale “inner awareness” was not significantly correlated with measures of depression (BDI-II) and worry (PSWQ) indicates that this subscale measures a construct distinct to negative mental health. The same results were found in non-clinical sample 1, except that in addition, “openness” was not significantly correlated with measures of self-compassion (SCS), depression (BDI-II), or worry (PSWQ) and that “relativity” showed no correlation with depression (BDI-II) and worry (PSWQ).
Table 4
Pearson correlations between the CHIME and other constructs
Clinical sample, n = 232 |
Mindfulness (FFMQ) |
FFMQ observe | .59** | .84** | .18** | .15* | .21** | − .04 | .15* | .30** |
FFMQ describe | .41** | .19** | .25** | .27** | .31** | .14* | .29** | .30** |
FFMQ acting | .45** | .43** | .49** | .40** | .41** | .16* | .19** | .38** |
FFMQ judging | .07 | .09 | .29** | .57** | .38** | .37** | .17* | .15* |
FFMQ reacting | .19** | .24** | .33** | .58** | .77** | .16* | .41** | .43** |
Self-compassion (SCS)1 | .27** | .28** | .41** | .70** | .69** | .15* | .46** | .59** |
Worry (PSWQ) | − .12 | − .23** | − .46** | − .63** | − .67** | − .21** | − .30** | − .40** |
Depression (BDI-II) | − .11 | − .17** | − .49** | − .57** | − .48** | − .24** | − .25** | − .37** |
Non-clinical sample 1, n = 127 |
Mindfulness (FFMQ) |
FFMQ observe | .42** | .82** | − .16 | .18* | .15 | .12 | .28** | .44** |
FFMQ describe | .40** | .26** | .36** | .22* | .34** | .17 | .18* | .35** |
FFMQ acting | .41** | .32** | .38** | .12 | .12 | .21 | .12 | .23** |
FFMQ judging | .03 | .23* | .17 | .39** | .12 | .34** | .04 | .11 |
FFMQ reacting | .17 | .21* | .29** | .47** | .72** | .24** | .29** | .32** |
Self-compassion (SCS)2 | .25** | .34** | .24** | .77** | .60** | .10 | .18* | .45** |
Worry (PSWQ) | − .15 | − .24** | − .38** | − .43** | − .59** | − .13 | − .05 | − .29** |
Burnout (MBI) | − .14 | − .26** | − .32** | − .22* | − .29** | − .16 | − .04 | − .24** |
Sensitivity to Change
The scores on all subscales of the CHIME increased significantly over the course of an MBCT/MBSR training in both the clinical and non-clinical sample 1 (see Table
5). Effect sizes (Cohen’s
d) were small to moderate, ranging from .33 (openness) to .70 (insight) in the clinical sample and .20 (acting with awareness) to .66 (decentering/nonreactivity) in the non-clinical sample.
Table 5
Sensitivity to change of the CHIME and CHIME-SF
Clinical sample (MBCT), n = 149 |
Inner awareness | 19.15 (4.40) | 20.83 (3.41) | < .001 | 0.38 | 11.81 (2.83) | 12.46 (2.21) | < .001 | 0.23 |
Outer awareness | 15.97 (4.47) | 18.08 (3.86) | < .001 | 0.47 | 12.14 (3.55) | 13.83 (2.99) | < .001 | 0.47 |
Acting with awareness | 12.97 (3.52) | 14.15 (3.19) | < .001 | 0.34 | 8.62 (2.81) | 9.72 (2.69) | < .001 | 0.39 |
Acceptance | 13.25 (4.69) | 16.28 (4.36) | < .001 | 0.65 | 8.17 (2.96) | 10.07 (2.65) | < .001 | 0.64 |
Decentering/nonreactivity | 16.83 (5.00) | 19.98 (4.74) | < .001 | 0.63 | 7.90 (2.56) | 9.60 (2.57) | < .001 | 0.67 |
Openness | 13.01 (3.31) | 14.09 (3.28) | < .001 | 0.33 | 9.66 (2.73) | 10.74 (2.67) | < .001 | 0.40 |
Relativity | 13.14 (2.98) | 14.93 (2.79) | < .001 | 0.60 | 9.91 (2.47) | 11.27 (2.34) | < .001 | 0.55 |
Insight | 15.64 (3.69) | 18.21 (3.88) | < .001 | 0.70 | 9.01 (2.94) | 10.99 (2.99) | < .001 | 0.67 |
Non-clinical sample 1 (MBSR), n = 93 |
Inner awareness | 18.82 (3.51) | 20.46 (3.66) | < .001 | 0.47 | 11.86 (2.20) | 12.34 (2.12) | 0.017 | 0.22 |
Outer awareness | 15.85 (3.95) | 17.80 (3.67) | < .001 | 0.49 | 11.89 (3.12) | 13.56 (2.79) | < .001 | 0.54 |
Acting with awareness | 15.76 (3.27) | 16.40 (3.04) | 0.016 | 0.20 | 11.13 (2.79) | 11.58 (2.50) | 0.036 | 0.16 |
Acceptance | 15.62 (4.80) | 18.34 (4.01) | < .001 | 0.57 | 9.82 (2.99) | 11.34 (2.59) | < .001 | 0.51 |
Decentering/nonreactivity | 18.96 (4.50) | 21.94 (3.90) | < .001 | 0.66 | 9.28 (2.46) | 10.92 (2.20) | < .001 | 0.67 |
Openness | 14.27 (3.08) | 15.44 (3.29) | < .001 | 0.38 | 10.89 (2.51) | 11.94 (2.64) | < .001 | 0.42 |
Relativity | 13.97 (3.31) | 15.35 (3.10) | < .001 | 0.42 | 10.54 (2.43) | 11.55 (2.43) | < .001 | 0.42 |
Insight | 17.21 (3.95) | 19.38 (4.06) | < .001 | 0.55 | 10.01 (3.27) | 11.66 (3.04) | < .001 | 0.50 |
Evaluation of the CHIME-SF
Based on statistical and content-related considerations described above, 24 items were selected for the CHIME-SF. The items of the CHIME-SF can be found in the Appendix. As with the CHIME, a 1-factor model assuming that all items load on one unidimensional construct showed a poor fit with the data, whereas both 8-factor models showed a good model fit, with the correlational 8-factor model performing slightly better than the hierarchical model (see Table
2). To test configural invariance, the model fit of the correlational 8-factor model was tested separately for the clinical and non-clinical group. After that, the model fit in a multiple group analysis was tested. In both separate analyses (clinical group:
χ2 = 349.16, df = 224,
χ2/df = 1.55, CFI = 0.94, RMSEA = 0.049 [90% CI 0.039, 0.059], SRMR = 0.06; non-clinical group:
χ2 = 455.99, df = 224,
χ2/df = 2.04, CFI = 0.91, RMSEA = [90% CI 0.056, 0.073], SRMR = 0.06) and the multiple group analysis (
χ2 = 805.14, df = 448,
χ2/df = 1.79, CFI = 0.93, RMSEA = 0.04 [90% CI 0.036, 0.045]), the model fit was satisfactory. This shows that the global factor structure of the CHIME-SF is the same for the clinical and non-clinical group (configural invariance). Next, we constrain the factor loadings to be the same across both groups (metric invariance), which revealed a satisfactory model fit,
χ2 = 817.14, df = 464,
χ2/df = 1.76, CFI = 0.93, RMSEA = 0.04 [90% CI 0.035, 0.044]. Model comparisons of the configural and metric invariance models indicate noninvariance (∆CFI = 0.001, ∆RMSEA < 0.01). This indicates configural and metric invariance of the CHIME-SF across clinical and non-clinical groups.
The uncorrected and corrected correlations between the CHIME and the CHIME-SF were high: for “inner awareness” the correlation was r = .91 (rc = .74), for “outer awareness” r = .98 (rc = .88), for “acting with awareness” r = .95 (rc = .72), for “acceptance” r = .97 (rc = .86), for “decentering/nonreactivity” r = .94 (rc = .86), for “openness” r = .97 (rc = .69), for “relativity” r = .95 (rc = .75), for “insight” r = .93 (rc = .82). This shows that the CHIME-SF and the CHIME measure highly related constructs.
When investigating the sensitivity to change, the CHIME-SF performed very similar to the CHIME, with significant increases on all subscales and comparable effect sizes (Table
5).
The internal consistency of the CHIME-SF ranged from
α = .65 for “openness” to
α = .88 for “decentering/nonreactivity,” see Table
6. In order to investigate whether the CHIME-SF and CHIME represent the same content, correlations with other measures were compared. The correlations of the CHIME-SF with other measures (Table
7) were very comparable to those of the CHIME (Table
4). This indicates that the CHIME and CHIME-SF show comparable discriminant and convergent validity (Table
7).
Table 6
Correlations of subscales of the CHIME-SF
Inner awareness | .70 | – | | | | | | |
Outer awareness | .88 | .52** | | | | | | |
Acting with awareness | .73 | .20** | .25** | | | | | |
Acceptance | .82 | .32** | .34** | .46** | | | | |
Decentering/nonreactivity | .86 | .31** | .32** | .45** | .66** | | | |
Openness | .65 | .22** | .22** | .32** | .42** | .41** | | |
Relativity | .76 | .34** | .32** | .22** | .48** | .53** | .24** | |
Insight | .85 | .35** | .44** | .31** | .51** | .56** | .25** | .52** |
Table 7
Pearson correlations between the CHIME-SF and other constructs
Clinical sample, n = 232 |
Mindfulness (FFMQ) |
FFMQ observe | .51** | .86** | .16** | .15** | .11** | .01 | .20** | .27** |
FFMQ describe | .36** | .19** | .24** | .30** | .29** | .15* | .30** | .28** |
FFMQ acting | .43** | .41** | .47** | .41** | .33** | .20** | .22** | .37** |
FFMQ judging | .05 | .08 | .26** | .57** | .38** | .36** | .19** | .17** |
FFMQ reacting | .17** | .21** | .34** | .56** | .78** | .17** | .45** | .43** |
Self-compassion (SCS)1 | .25** | .28** | .43** | .69** | .65** | .20** | .52** | .56** |
Worry (PSWQ) | − .09 | − .22** | − .48** | − .62** | − .70** | − .22** | − .33** | − .43** |
Depression (BDI-II) | − .07 | − .17** | − .53** | − .57** | − .50** | − .27** | − .27** | − .39** |
Non-clinical sample 1, n = 127 |
Mindfulness (FFMQ) |
FFMQ observe | .33** | .86** | − .12 | .22** | .15 | .17* | .25** | .38** |
FFMQ describe | .36** | .27** | .33** | .26** | .30** | .20* | .16 | .27** |
FFMQ acting | .36** | .32** | .40** | .15 | .07 | .25** | .13 | .14 |
FFMQ judging | − .05 | .21** | .16 | .39** | .17* | .34** | .00 | .10 |
FFMQ reacting | .16 | .19** | .26** | .45** | .78** | .26** | .31** | .24** |
self-compassion (SCS)2 | .20* | .33** | .19* | .79** | .59** | .14 | .23* | .40** |
Worry (PSWQ) | − .09 | − .18* | − .40** | − .40** | − .61** | − .13 | − .08 | − .27** |
Burnout (MBI) | − .10 | − .24* | − .32** | − .23* | − .24** | − .19* | − .08 | − .22* |
Discussion
This study had three aims. First, the CHIME was translated into Dutch according to a standardized procedure. Secondly, the psychometric properties and sensitivity to change of the Dutch CHIME were evaluated. The third aim was to develop a short form of the CHIME with similar psychometric properties and validity.
The CHIME was translated according to a standardized procedure and the model fit was evaluated in a large mixed sample (
N = 481) consisting of one clinical sample and two non-clinical samples. The CFA showed an acceptable model fit for the correlated 8-factor structure of the CHIME. This result is in line with the results of the original validation study of the German CHIME (Bergomi et al.
2014) and confirms that the Dutch version of the CHIME measures eight distinct but related aspects of mindfulness skills. However, one item (item 3) had a low factor loading (< .40), indicating that this item contributed minimally to the subscale “insight.” Nevertheless, internal consistency of this subscale (Cronbach’s
α = .79) is considered sufficient for research purposes. Future research should evaluate whether this item is also problematic in other populations and if adaptation of the CHIME is necessary. We found configural and metric invariance across the clinical and non-clinical participants, which indicates that the global factor structure of the CHIME is stable across these groups. In line with the original validation study (Bergomi et al.
2014), the CHIME’s construct validity was confirmed by the correlations with discriminant and convergent constructs. The correlations with a distinct mindfulness skills questionnaire, self-compassion, measures of psychopathology (depressive symptoms, burnout), and worry met the predictions about their direction and magnitude. Sensitivity to change analysis showed significant effects of mindfulness-based interventions on the CHIME with small to moderate effect sizes. The largest changes were found for the subscales acceptance, decentering/nonreactivity, and insight, which is again consistent with the original validation study (Bergomi et al.
2014). These results were found in both the clinical and a non-clinical sample, indicating that the Dutch CHIME is an adequate measure to assess change in mindfulness skills in patients as well as in community samples.
Overall, the results indicate that the Dutch version of the CHIME is a valid measure to assess mindfulness skills. The CHIME covers aspects of mindfulness that are not included in the FFMQ, reflected in the subscales openness to experiences, awareness of thought’s relativity, and insightful understanding. Therefore, the CHIME could be particularly useful in research on the differential effects of mindfulness facets and their association with related measures.
The evaluation of the CHIME-SF indicated that the short form we developed was sufficiently reliable and valid. CFA showed a good model fit for the correlated 8-factor structure which was even better compared to the long version CHIME. This may be explained by the fact that items with low factor loadings (including item 3) were eliminated. Furthermore, the internal consistency, convergent and divergent validity, and sensitivity to change of short form also remained similar to the full-length form. In addition, high corrected correlations were found between the short form and the full-length form. These results indicate that the content validity and the psychometric properties were sufficiently preserved in the short form. Previous research has shown that short forms of questionnaires can have as much predictive value as the full version of a questionnaire (Thalmayer et al.
2011). The CHIME-SF seems to be a useful instrument to assess mindfulness skills in research designs including a large number of other instruments or repeated measures. However, until the validity of the CHIME-SF is further evaluated in an independent sample and because full versions in general cover the assessed concept more broadly, the full CHIME should be preferred if time allows.
Limitations and Suggestions for Future Research
A limitation of this study is that the full and the short form were assessed in the same samples. To compare the forms, we used corrected correlations; however, the factor structure of the CHIME-SF should be confirmed in an independent sample. Second, the test retest reliability of the Dutch CHIME should be assessed to make sure that the increase in scores after a mindfulness intervention is not due to measurement error. Third, although we found indications for configural and metric invariance of the CHIME and CHIME-SF across clinical and non-clinical participants, further studies should investigate scalar and residual invariance before mean scores of patients and community samples can be compared. Fourth, it would be valuable to further investigate the sensitivity to change and whether changes in the CHIME are correlated with changes in psychiatric symptoms or well-being. Although the current sample was rather large, response rate after the MBCT/MBSR was not optimal which may have resulted in selection bias with an overrepresentation of participants who benefited from the mindfulness intervention. Additionally, our samples included relatively few men. Finally, translating the CHIME into other languages would increase the accessibility of the questionnaire.
Acknowledgements
The authors would like to thank Katharina Müllen, Jette van Ravesteijn, Hylco Nijp, and members and students of the Radboud Center for Mindfulness for help with translating the questionnaire.
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