Descriptives and Reliability of the Instruments (Sample 1 and Sample 2)
Means and standard deviations for both samples are reported in Table 1. The means of the 24 character strengths, on a potential range from 1 to 5, ranged from 2.45 (spirituality, VIA-120, Sample 2) to 4.25 (honesty, VIA-120, Sample 2).
Table 1 Character strength measures Standard deviations ranged from 0.45 (honesty, VIA-120, Sample 2) to 1.02 (spirituality, VIA-120, Sample 2). Skewness and kurtosis of the VIA-240 and the VIA-120 (Sample 1 and Sample 2) were in an acceptable range (±1). The three character strengths with the highest means were the same in both samples regardless of the VIA-questionnaire versions: honesty, kindness and fairness. The character strength spirituality had the lowest mean score, independent of the sample or instrument used (Table 1). The means of the CSRF scales as well as the differences regarding the level of character strengths based on the VIA-120 between the two samples can be found in Table 1.
The internal consistencies of the 24 VIA-120 scales ranged from α = .58 (modesty, Sample 1) to α = .90 (spirituality, Sample 2). The alphas of the VIA-240 scales (Sample 1) ranged from α = .75 (modesty) to α = .91 (spirituality). The average alpha of the VIA-240 (α = .82) was slightly higher compared to the VIA-120 (α = .76, α = .72), which can be expected due to the higher number of items per scale (10 vs. 5). In 8 out of 24 scales Cronbach’s alpha of the VIA 120 (Sample 1 and 2) was more than 0.10 points lower than the VIA-240 version, with a maximum divergence of .18 points for the character strength teamwork. Average inter-item correlations per scale for all versions ranged from 0.23–0.47 (VIA 240), 0.22–0.57 (VIA 120, Sample 1) and 0.26–0.63 (VIA 120, Sample 2). Acceptable values range from 0.15 to 0.50 (Clark and Watson 1995), with less than 0.15 indicating poor inter-correlation and greater than 0.50 indicating content repetition. Overall the average inter-item correlation showed good overlap, however, the scale spirituality of the VIA 120 reached in both samples critical values (0.57; 0.63 respectively) indicating that the meaning of the items could be considered repetitive (Table 1). The comparison of the VIA 240 and VIA 120 scale scores showed nevertheless a high overlap (Table 1).
Sample 1 had significantly lower SWLS scores (23.14 ± 6.37) than Sample 2 (26.74 ± 4.96) (p < .001). The BIT had a mean of 4.06 (±.48).
The correlation among the scales for the VIA 240 ranged from 0.22 (Spirituality x Enthusiasm) to 0.78 (Hope x Teamwork), for the VIA 120 (Sample 1) from 0.10 (Modesty x Curiosity) to 0.77 (Enthusiasm x Humor) and for the VIA 120 (Sample 2) from 0.08 (Courage x Modesty) to 0.49 (Open minded x Love of learning).
Validity: Associations of the VIA with Measures of Well-Being and Strengths
Convergent Validity (Sample 1)
Correlations adjusted for item overlap between the scales of the VIA-240 and the respective scales of the VIA-120 (Sample 1) showed high, effect sizes ranging from r = .52 (hope) to r = .89 (prudence), with a median correlation of r = .77 (Table 1). The correlation between the rank orders of the strengths obtained in the VIA-240 and the VIA-120 Sample 1 was .86 (Sample 1).
The scales of the CSRF were correlated with the respective VIA-240 and VIA-120 scores in Sample 1. Correlations were all highly significant and ranged from r = .44 (curiosity, VIA-120 Sample 1) to r = .74 (spirituality, VIA-240, 120 both Sample 1), with only two character strengths showing moderate correlations: curiosity (r = .44) and prudence (r = .46) with the CSRF. The correlation between the rank orders of the strengths obtained in the CSRF and VIA-120 Sample 1 was .76.
Criterion Validity (Sample 1 and Sample 2)
Regarding the criterion validity, the VIA-240 scales were correlated with the SWLS and the CSRF. The VIA-120 scales obtained from the same sample (Sample 1) and the independently administered VIA-120 (Sample 2) were both correlated with the SWLS. Moreover, the well-being measure BIT was correlated with the VIA-120 scale (Sample 2).
Correlations with the SWLS ranged from r = .14 (modesty, VIA 240) to r = .56 (hope, VIA 240), from r = .12 (modesty, VIA-120, sample) to r = .58 (hope, VIA-120, Sample 1) and from r = .05 (modesty) to r = .52 (hope, VIA-120 Sample 2, Table 2). Correlation coefficients showed equally strong effect sizes for all versions of the VIA for the character strengths hope and zest, equally moderate for Curiosity, Gratitude and Love and equally weak for appreciation of beauty and excellence, fairness, honesty, learning, prudence and social intelligence. Inconsistent correlations were found between the VIA-240 and the VIA-120 in both samples for forgiveness, humor, perseverance, perspective, self-regulation, and teamwork with all at least moderate correlations between the VIA-240 and the SWLS and only weak correlations between both VIA-120 samples and the SWLS. Further, the VIA-120 scales in the independently administered Sample 2 showed lower correlations with the SWLS. All correlations were significant except for modesty, courage, creativity, and spirituality.
Table 2 Reliability and validity statistics The correlations of the two VIA versions in the two samples with the SWLS were tested for significant differences. The correlations of the VIA 240 and VIA 120 (both Sample 1) with the SWLS were not significantly different from each other; however 14 correlations of the VIA120 (Sample 2) with the SWLS were significantly lower than the respective VIA 240 correlations. Only 5 correlations of the VIA 120 (Sample 2) with the SWLS were significantly lower than the respective VIA 120 correlations (Sample 1).
The hypothesized highest correlations between the character strengths curiosity, gratitude, Hope, love and zest (any VIA questionnaire version, both samples) and SWLS could be found in the data (Table 2; all r ≧30); Also Humor (any VIA questionnaire version, both samples) and SWLS were significantly correlated with SWLS however only at r .20. Spirituality was only related for the VIA-240 and VIA-120 (Sample 1) with SWLS r = .27, r=. 22 respectively and not on VIA-120 (Sample 2, r = .06).
A similar pattern could be found for the correlations of the BIT with the VIA-120 (Sample 2). Curiosity, Gratitude, Hope, Humor, Love and Zest were significantly correlated with the BIT having a moderate to high effect size. Spirituality was significantly correlated with the BIT, however only with a weak effect size.
Factor Structure of the German 120-Item Version of the VIA-IS (Sample 1 and Sample 2)
Factor structures (principal axis factoring with promax rotation, power = 4) of the scales of VIA-120 (both samples) were compared with the factor structure of the VIA-240 (Sample 1, Table 3). The previously established five-component solution could be replicated with both versions (e.g., Littman-Ovadia & Lavy, 2012; Ruch et al. 2010). The variance accounted for 64.38% and 57.82% in the data for the VIA-120 and 72.69% for the VIA-240. In line with previous studies (e.g., Ruch et al. 2010; Littman-Ovadia 2015; Azañedo et al. 2017) the five factors identified were labelled as follows: (1) emotional character strengths, (2) interpersonal character strengths, (3) character strengths of restraint, (4) intellectual character strengths, and (5) theological character strengths. We found that seven VIA-240 scales and seven VIA-120 (Sample 1) scales demonstrated double loadings (difference ≤ .10 between scales’ loadings, criterion according to Ruch et al. 2010) and that two character strengths (hope and open-mindedness) of the VIA-120 did not load on the same factors as in the VIA-240 (theological vs. emotional and restraint vs. intellectual character strengths). Further the character strength love in both versions did not load as in previous publications on the factor emotional character strengths (Littman-Ovadia 2015; Ruch et al. 2010) but on the factors interpersonal (VIA-240) and theological strengths (VIA-120). Tucker’s Phi indicated for the VIA-120 an acceptable level of congruence with the VIA – 240 ranging from .93 (intellectual character strengths) to .99 (emotional, interpersonal, restraint and theological character strengths) for Sample 1 and .95 (emotional, interpersonal and intellectual character strengths), .97 (theological character strengths) and .98 (restraint character strengths) for Sample 2.
Table 3 Factor analyses* structure matrix results for the German original VIA-240 and the VIA-120 (Sample 1 and Sample 2) Our results indicated a sufficient convergence between the factor structures of the original and the short form (Table 3).