Variability analysis for 4 Prosite families. Variability analysis of the fourteen significance measures for four Prosite family entries: PS00978, PS001172, PS00076 and PS00021. For each family dataset, rigid gap motifs were extracted with a minimum support value equal to 80% of the Sn value of the Prosite target motif (signature motif of the family). For easier visualization, score values were normalized to the [0, 1] range. The number of evaluated motifs was respectively for each family: 94, 196, 20 and 88. Each line in the figure (plotted with different colors) represents the scores of a motif. Measures where the majority of their lines overlap have low variability. It can be seen that in general non class-based measures have greater variability.