A systematic review of quantitative studies testing Nonviolent Communication training interventions

Introduction Nonviolent Communication (NVC) is a framework claimed to enhance communication, empathy, and peaceful conflict management. Despite numerous claims it is unclear what empirical scientific evidence supports NVC. The aim of this paper is to synthesize and critically assess empirical, quantitative evidence testing the effectiveness of NVC training interventions. Methods A literature search was conducted across scholarly databases, yielding 31 eligible studies. We assessed per-study risk of bias using ROBINS-I and Cochrane RoB. Evidence was then synthesized by outcome variable and separately for within-group pre-post designs and between-group controlled intervention designs using GRADE. Results Among pre–post designs, empathy was assessed in 16 studies (total number of participants N = 909), self-compassion in 5 studies ( N = 246), expressed anger and aggression in 6 studies ( N = 223), and communication competence in 6 studies ( N = 306). The certainty of evidence was low for empathy, moderate for self-compassion, low for communication competence, and very low for expressed anger and aggression. Among intervention versus control designs, empathy was assessed in 11 studies ( N = 1,367), self-compassion in 4 studies ( N = 460), expressed anger and aggression in 6 studies ( N = 438), and communication competence in 6 studies (N = 408). The certainty of evidence for intervention versus control-group comparisons was moderate for empathy, low for self-compassion, moderate for communication competence, and very low for expressed anger and aggression. Discussion The majority of studies lack adequate control conditions or randomization, which limits conclusions that can be drawn. Furthermore, many interventions have been tested in specific contexts such as prisons or hospitals which makes it difficult to generalize the findings. Research to date is almost exclusively based on self-report measures. We propose that future studies could investigate whether observable behaviors change as a function of NVC training. The present work nuances the commonly held assumption that NVC is effective in improving social functioning across contexts and points to a more modest pattern of potentially effective uses.