Table 6.

Mean differences, standard deviation, t-scores (paired), p-values, effect size d and its interpretation between the accumulated days with (17) and without NSSI (172) of our ten participants who have shown NSSI regarding the imagery characteristics, affect, and entrapment beliefs in the diary

	Mean difference NSSI-days, noNSSI-days (SD)	t	pa	db	Interpretation
Compellingness	.90 (1.79)	1.58	.15	.56	Medium
Vividness	−.47 (2.45)	−.61	.56	−.29	Small
Controllability	−1.14 (1.84)	−1.97	.08†	−.89	Large
Nowness	−.03 (1.69)	1.55	.96	−.02	–
Distress	−.16 (1.58)	−.32	.75	−.09	–
Comfort	1.14 (2.33)	1.58	.16	.43	Small
Daily positive affect	−.30 (.41)	−2.26	.05†	.50	Medium
Daily negative affect	.62 (.94)	2.08	.07†	.74	Medium
Positive affect after image	.17 (.68)	.78	.45	.24	Small
Negative affect after image	.26 (.90)	.90	.39	.28	Small
Entrapment	.51 (1.13)	1.42	.19	.47	Small

^alevel of significance: †: p < .10

^bregarding the effect size, we first obtained the d_z for paired t-tests which, however, overestimates the effect size compared to independent groups and should therefore be adjusted (e.g., [67]), and therefore obtained the d_av according to Cumming [68]