A Systematic Review of 50 Years of Literature on the Effects of Forgiveness Interventions

The main purpose of this study is to systematically examine research conducted over the past 50 years regarding the effectiveness of forgiveness interventions in achieving clinical treatment goals. A computer search was conducted in the following data bases: Academic Search Premier; Alt HealthWatch; CINAHL with Full Text; Education Full Text; Education Research Complete; Eric; Health Source: Nursing/Academic Edition; MEDLINE; Psychology and Behavioral Sciences Collection; PsycINFO; Social work abstracts; SocINDEX. Studies used in this systematic review were gathered from these electronic search engines using the key terms forgiv* and intervention, treatment, therapy, program, workshop, trial, seminar, and program.

This strategy produced more than one thousand studies, which were manually reviewed for possible inclusion. In order to be included, studies had to (1) be published in a peer-reviewed journals from 1967 to 2016; (2) be written in English; (3) analyze the effectiveness of forgiveness-focused interventions; and (4) use a quantitative design. There were 384 peer-reviewed studies. Of these, 47 studies were met the criteria and included in this analysis. The soundness of the empirical evidence was assessed according to sampling strategy, randomization, and the quality of research methodology.

The present study has used the same methodology as that used by Johnson et al. (2000). The quality of the studies was assessed using criteria developed by Cook and Campbell (1979). Eleven criteria are utilized to assess the quality of research. Each of these eleven criteria was coded as dichotomized outcome. Presence of these criteria was coded 1 and the absence as 0.

The 47 articles used in the present study had an average score of .8 on the quality index, which has a score range of 0 to1. It was much higher compared to previous systematic reviews (e.g. .53, .59) by previous systematic reviews. The majority of the studies (77%) used randomized pretest-posttest designs which greatly reduces the threat of spuriousness. The intra-rater reliability was .89 for all measures examined.

Consistent with previous literatures that support the effectiveness of forgiveness interventions dealing with transgressions and mental health issues, no study in this review suggests an adverse effect of forgiveness interventions on clinical problems people faced. However, four studies showed mixed effect that some dimensions of forgiveness interventions had no effect on ability to forgive and/or mental health issue. These four studies were ranked a little higher in terms of quality index (.81) than the rest of the studies that supported the effectiveness of forgiveness interventions (.8).

Overall, the present study supports that forgiveness interventions may play an important role in reducing unforgiveness and improving mental health. However, it appears to be several unresolved issues around why certain types of interventions work better than others. The results of the present study indicate that a fuller understanding of various factors (e.g. the role of gender, the mode of delivery (individual vs group), the use of faith, the length or design of the intervention, the level of distress/hurt/injustice) may be vital to addressing what accurately contributes to the effectiveness of forgiveness interventions.