After the secondary structure prediction of the GRAMPA sequences with experimentally resolved structure, we calculated the Jensen-Shannon distance between the secondary structure probability distributions of each prediction method and the experimental reference. The Jensen-Shannon distance is calculated from the square root of the Jensen-Shannon divergence and makes it possible to measure the similarity between two probability distributions , it is based on the Kullback-Leibler divergence, with the advantage of being symmetric. The Jensen-Shannon distance is defined as: