In terms of the gold standard set out by bodies such as APA for psychotherapy research, EFT epitomizes the very highest level set out by this standard. Over the last 30 years, the EFT research program has systematically covered all the factors set out in optimal models of psychotherapy research.The meta-analysis (Johnson et al, 1999) of the four most rigorous outcome studies conducted before the year 2000, showed a larger effect size (1.3) than any other couple intervention has achieved to date. Studies consistently show excellent follow-up results, and some studies show that significant progress continues after therapy. EFT has a body of process research showing that change does indeed occur in the way that the theory suggests. This level of linkage between in-session process and rigorous outcome measurement is unusual in the field of psychotherapy.
EFT is the only model of couple intervention that uses a systematic empirically validated theory of adult bonding as the basis for understanding and alleviating relationship problems. The generalizability of EFT across different kinds of clients and couples facing co-morbidities such as depression and PTSD has been examined and results are consistently positive. Outcome and process research addressing key relationship factors, such as the forgiveness of injuries, has also been conducted with positive results. EFT studies are generally rigorous and published in the best peer reviewed journals.
You can access additional information on this by referring to: http://www.iceeft.com/images/PDFs/EFTResearch.pdf