Division 9 For those guidelines which allow for study to be designed to determine an effective concentration (ECx), the study shall be conducted to determine an EC10 and EC20 along with corresponding 95 % confidence intervals. If an ECx approach is used, a NOEC shall still be determined.
United Kingdom
Existing acceptable studies that have been designed to generate a NOEC shall not be repeated. An assessment of the statistical power of the NOEC derived from those studies shall be carried out.