I think WHO report is really based on an unsubstantial data. I looked into what “preliminary” means by them. Please refer to page 13 of this phrase “The WHO report is based on preliminary and include only data that were available as of September 2011.” in their website http://apps.who.int/iris/bitstream/10665/78218/1/9789241505130_eng.pdf
Here is information I found out in the various sources in Japanese official source:
Thyroid examination hasn’t started till October 2011. So it looks like the data base the WHO used were what Fukushima Health Survey group did before the end of September, 2011 that was:
1. Thyroid screening examination with 1080 children in Namie-machi, Kawamata-machi and Iwaki-city at the end of March, 2011. The Japanese Government admitted in NHK Special TV program called “Searching for missing Iodine data” that thyroid screening test wasn’t good enough to conclude a level of exposure to ionizing radiation of the thyroid in the children because the equipment could only detect a level of ionizing radiation from a whole body. Also I would like to add that although this equipment detect a level of ionizing radiation from a whole body, it only detect gamma radiation, so any amount of exposure to alpha and beta radiation was not been able to detect.
(Source) 15m- http://www.dailymotion.com/video/xwpjzj_yyyyyyyy-yyyyyy131yyy-1_news#.UPNXevKk14J
2. Written health surveys reported by citizens of Fukushima prefecture with very small amount of collection rate
Fukushima Health Survey team started to distribute questionnaires to the citizens in the high dose areas (Kawamata, Namie, Iidate, 29,000 people in total) at the end of June, 2011. The content of questionnaires is where they were, what they did and ate between 11/3/11-25/3/11. The collection rate was 47% as of the end of September, 2011. For the distribution of the survey for the rest of the citizens in Fukushima prefecture (about 1,970,000) had started at the end of August, 2011. The collection rate was 3.8% as of the end of October. This survey was reported extremely unpopular due to various misleading safety campaigns by the Fukushima government and the Health Survey Team. Therefore people in Fukushima didn’t want to be corporative.
(Reference) Fukushima Heath Survey Report:
WHO - There is no independent authority concerned with radiation and health issues!
The WHO report is clearly a political statement to protect the nuclear industry and not a scientific one with people’s health in mind.”
WHO Fukushima Report Methodology & Crisis Management Failure
Ties to International Atomic energy Agency sonctrain World Health Organisation's Fukushima radiation report
“Shameless”: New World Health Organization report shockingly downplays health risks after Fukushima – “WHO and other organizations must stop hiding the impact”
*WHO downplayed health effects of nuclear crisis on Fukushima residents: German physician