The issue of blinding has been addressed as a design technique to minimize bias in the International Conference on Harmonization (ICH) E9. However blinding can be very hard to establish and maintain. Methods of assessing and reporting the effectiveness of blinding are debatable and no clear guidance for analyzing and reporting the blinding exits. We would like to discuss the current available methods for analyzing and reporting the blinding.

Three key questions: (1) What methods could be used to achieve blinding in pharmaological therapy thials and medical device trials? (2) How and when can the blindling be assessed? (3) What analytical methods can be used to assess blinding effectiveness? How will the results be interpreted and reported?