(this short form of the self-compassion scale is downloadable both as a PDF file and as a Word doc) 

It's still early days, but there's an encouraging groundswell of research emerging on compassion and especially self-compassion.  See for example this website's recent post on Willem Kuyken et al's "under review" study "How does mindfulness-based cognitive therapy work?", the many publications and links to be found at "The compassionate mind foundation", information and fascinating videos at Stanford's "Center for compassion and altruism research and education", this site's "Compassion & criticism" page, the University of Michigan's "Self and social motivation lab", and possibly most usefully, the many resources - including downloadable free full text articles - at Kristin Neff's "Self-compassion" website. 

Probably the most usual way to measure self-compassion has been Kristin Neff's original 26-item, 6-subscale full Self-Compassion Scale (SCS).  A problem with this full scale is the time needed to score it.  This isn't just because it involves 26 items; it's also because many of the answers need to be "reverse scored".  To make matters still more time-consuming, Kristin also suggests that one should work out average scores for each subscale and for the scale as whole.  This overall time demand has meant that I've never used the full SCS to monitor ongoing treatment on a session by session basis.

Happily there is now an article by Raes, Pommier, Neff & Gucht in press with the Clinical Psychology & Psychotherapy journal entitled "Construction and factorial validation of a short form of the Self-Compassion Scale".  The article abstract reads - "The objective of the present study was to construct and validate a short form version of the Self-Compassion Scale. Two Dutch samples were used to construct and cross-validate the factorial structure of a 12-item Self-Compassion Scale-Short Form (SCS-SF). The SCS-SF was then validated in a third, English sample.  The SCS-SF demonstrated adequate internal consistency (Cronbach's alpha ≥ .86 in all samples) and a near-perfect correlation with the long form SCS (r ≥ .97 all samples). Confirmatory factor analysis on the SCS-SF supported the same six-factor structure as found in the long form, as well as a single higher-order factor of self-compassion. The SCS-SF, thus, represents a reliable and valid alternative to the long form SCS, especially when looking at overall self-compassion scores."

The full text of the article is freely downloadable from Kristin Neff's site by clicking here and I've also put together downloadable Word doc and PDF file versions of this easily scored, 12-item, short form Self-Compassion Scale.  Good, a useful step forward in making self-compassion easier to measure and monitor - especially for teachers and therapists.