Decomposition of error rate variation, using all available variables. For each plate, we used a logistic model to decipher the role of each selected variable and its contribution to error rate (see materials and methods). The error rate has been broken down as a function of error type: a) insertions, b) deletions, c) mismatches and d) ambiguous base calls. We tested the deviance from the complete model by breaking down the complete model into the sum of three terms: the first exclusive to the single effect of the variable considered (in black), the second exclusive effect of the rest of the variables without the variable of interest (in gray) and the last expressing the sum of the effects of interactions between the variable considered and the other variables (in white). The contribution of each term (the proportion) for a considered variable can be viewed on the y-axis. We display only the results for plate #1 (the results for the other plates are presented in additional file 3).