Interobserver variabilities in MIB-1-LI results, four months later: MIB-1-LI data obtained by 15 pathologists on centrally immunostained slides of three moderately differentiated breast carcinomas, assessed by eyeballing (A,B) and counting (C,D).

<p>Shown are for each pathologist the fraction of MIB-1-LI results over the mean value calculated for the entire group of 15 pathologists. Red and yellow circles indicate results obtained in self- selected and predefined areas, respectively. Mean values are shown in horizontal bars. The interobserver variabilities were comparable to the results obtained four months prior on the same slides (see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0037379#pone-0037379-g004" target="_blank"><b>figure 4B</b></a>). The data shown in the right panels (B,D) were then modified by a “correction factor” for each individual pathologist. This correction factor was calculated from the results obtained on three independent carcinomas, see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0037379#pone-0037379-t003" target="_blank">Table 3</a>). Yet, this correction factor could not reduce the high interobserver variability, as evidenced by only slight reductions of the standard deviations (27⋅8 vs 30⋅4 for eyeballed and 22⋅5 vs 24⋅1 for counted data).