upheld two of the four challenges. They concluded that although there seemed to be some evidence of participant improvement during trials conducted, the trials were not controlled, the evidence was not sufficient to draw robust conclusions, and more investigation was necessary; consequently, the website's claims at the time were deemed misleading and was amended. Research A registered clinical trial (UK SMILE pilot study) was conducted in England at Bristol University, with results published in 2017. The results did not change the stance of the National Health Services in the United Kingdom which does not recommend the method. A peer reviewed qualitative study on experiences of the course among a group of young people with chronic fatigue syndrome was published in 2012. A Norwegian Support Group patient survey showed mixed experiences. Patient surveys are considered low quality evidence compared with peer reviewed studies. For various reasons they cannot answer questions about the results of intervention. A pilot intervention study exploring the efficacy of the Lightning Process training programme for reducing chronic fatigue and improving health-related quality of life in cancer survivors with reported significant fatigue issues were conducted at the National Cancer Hospital in Norway (Radiumhospitalet) and published in August, 2021. The study involved 13 participants and did not include a control group, which prevents causal attribution of any effect a given treatment may have. Significant improvement was reported at 3 and 6 months compared to baseline. No adverse effects were reported and the authors argued that a larger controlled clinical trial may be recommended. Given the limited clinical evidence, the National Institute for Health and Care Excellence (NICE) explicitly states that "[d]o not offer the Lightning Process, or therapies based on it, to people with ME/CFS" in their guideline for the management of ME/CFS published in 2021. Public reaction to research Esther Crawley said that "I never expected it would work" and that "This is an important study as it provides another treatment approach that some may find helpful. However, while these results are promising, further research is needed to establish which aspects of the process are helpful, whether it is an effective treatment on its own, and whether it could be used to help more severely affected patients." Research into chronic fatigue syndrome is often a target of criticism. The SMILE study received some public criticism for recruiting children when adult subjects are available. The study was approved by