A comparison of 11 steel gauge blocks (8 short and 3 long) calibrated by absolute interferometry is presented. Thus, the results of the individual measurements of five designates signatories (three from INTI and two from CENAM) were analyzed in order to evaluate the impact of possible correlations and systematic effects in the reproducibility of the measurements. All measurements were carried out in the framework of a bilateral key comparison between CENAM and INTI and following their own calibration procedures. The measurement analysis was performed by using inclusive and exclusive statistics. The agreement between all measurements is satisfactory and no detectable systematic effects were observed. Average offsets were also calculated for each operator verifying that systematic effects did not affect the measurements of the present exercise. Even though the approaches deployed to analyze the results are well-established, this work provides a detailed example of analysis in the field of gauge block metrology. This exercise has also allowed to validate the internal criteria considered by each institute for selecting final results.