Self-compassion—being understanding and accepting of one’s weaknesses and inadequacies —has been receiving increasing attention , particularly in the fields of mental health and psychology [4,5,6,7,8,9]. A meta-analysis of 20 studies reported large (as defined ) associations between self-compassion and various types of mental distress including depression and anxiety . Further, intervention studies found that enhancing self-compassion also improved various outcomes including mental health , well-being , and life satisfaction . These studies reported that practicing compassion towards one’s inadequacies and life challenges can counter shame and self-criticism, which otherwise might lead to poor mental health and well-being .
Self-compassion is most commonly regarded  as a healthful formulation of self-acceptance, based upon (i) self-kindness: an understanding of oneself when facing inadequacy, rather than self-criticism and self-judgement; (ii) common humanity: a notion that suffering is an unavoidable human condition, as opposed to viewing it as a source of isolation (e.g. ‘Why me?’); and (iii) mindfulness: being presently aware of hurtful thoughts, instead of over-identifying with them [1, 2]. These three components are theorised to interplay with each other: improvement in one element can lead to improvement in another . Self-compassion, therefore, is based on positive constructs of self-kindness, common humanity, and mindfulness and the absence of their opposites, the negative constructs of self-judgement, isolation, and over-identification . The positive constructs may be explained by significant relationships between self-compassion and positive affects (e.g. happiness and optimism) and personality traits (e.g. agreeableness) . On the other hand, the negative constructs may be explained by the strong associations with mental health problems (e.g. depression, anxiety, stress) and shame [2, 6,7,8,9, 17, 18].
The Self-compassion Scale (SCS; ) is the most commonly used measure of self-compassion in research , although other self-compassion scales have been developed recently (e.g. [19,19,21]). However, this 26-item scale has been criticised for its limited reliability; in Lopez et al.’s study (2015) of 1643 Dutch participants aged 20–97 years, confirmatory factor analyses (CFAs) could not replicate the original six-factor structure of the SCS. Indeed, exploratory factor analyses (EFAs) indicated a two-factor solution with the positive components (self-kindness, common humanity, and mindfulness) and the negatives ones (self-judgement, isolation, and over-identification), as the best fit model with good internal consistency. Similar results were also yielded in other studies, reporting a best and good fit of a two-factor solution [22,22,24]. Neff  attributed these poor fits with the six-subscale model to the language translation and the specific study contexts, in line with her previous research into differences of self-compassion in different cultures . However, the generalisability of SCS needs to be refined. Recently, following other research supporting the validity of SCS (Cleare et al., 2017; ), Neff et al.  conducted more comprehensive analyses (n = 11,685) which confirmed the reliability of the six-factor model of the SCS.
In order to reduce the time and effort for participants, a brief version of SCS, the 12-item Self-compassion Scale-Short Form (SCS-SF; ) was developed; this was particularly desirable in clinical research where patients often have to complete large batteries of assessments. The global score of SCS-SF was almost perfectly correlated with the global score of SCS . Raes et al. recruited two Dutch samples (271 undergraduate psychology students and 185 from general population), using the Dutch version of SCS, and one American sample (415 students), using the original English version of SCS. Raes et al. selected two items from each subscale that were strongly correlated with the global score of SCS and their intended subscale score (recommended by ), while qualitatively considering the breadth of the original subscale contents (to counter the risk of suboptimal content domain coverage; ). While the global SCS-SF score was almost perfectly correlated with the global SCS score (r ≥ .97), the internal consistencies of the subscales in the SCS-SF (the English version) were less good, varying between .54 and .75; hence, only the global SCS-SF score, and not the subscales, was recommended for use .
The validity of the SCS-SF has been tested in various populations. Among 594 randomly recruited elder participants, the Swedish SCS-SF did not yield reliable results. Good reliability was only found in the group of 66-year-olds (α > .70), and only the negative components of the two-factor model (self-judgement, isolation, and over-identification) showed good internal consistency, both in the entire sample and in the 66-year-old group . Likewise, Hayes, Lockard, Janis, and Locke (2016) explored the factor structure and construct validity of the SCS-SF for a clinical population (1609 American university students who have mental health problems), and could not replicate the six-subscale model, but identified a two-factor model: self-disparage and self-care. These were similar results to Costa et al. , who noted the two-factor model for the full SCS from other clinical populations. Lastly, Sutten, Schonert-Reichl, Wu, and Lawlor (2018) investigated 406 Canadian children between 8 and 12 years old, using the Self-compassion Scale for Children (SCS-C), an adjusted brief version of the SCS-SF to more children-friendly language, which, again, supported the two-factor model. Despite the significant differences of the levels of self-compassion in different cultures , the SCS-SF to date has not been evaluated in UK populations. Indeed, high internal consistency of SCS-SF in UK populations has been reported in recent studies (e.g. α = .90–.92 in n = 105; ; α = .84 in n = 145; Kotera, Green & Sheffield, 2019); however, these studies did not recruit a large sample and did examine neither the factor structure nor the construct validity of the scale. Accordingly, this study aimed to explore the factor structure, reliability, and construct validity of the SCS-SF in UK students. First, the factor structure was examined using CFA: whether we could replicate the hierarchical six-factor structure (as reported by ). Second, the reliability of the SCS-SF (internal consistency) was calculated. Lastly, the relationships between the SCS-SF and self-report measures regarding mental health, self-criticism, self-reassurance, mental health shame, emotional resilience (hereafter ‘resilience’), and mental well-being (hereafter ‘well-being’) were explored, in order to appraise construct validity of the SCS-SF.