Original sentence: However EFT warrants further research, because of the lack of a control group.However because of the small sample size and lack of a control group EFT therefore warrants further research
Edited sentence: However the small sample size and lack of a control group shows that no real conclusions can be drawn regarding the effectiveness of the treatment, and is a sign of poor experimental design.The lack of a control group shows that no real conclusions can be drawn regarding the treatment's actual effectiveness, and is a sign of a poor design