Subsequently, two separate studies of Morton's data and methods, one conducted in 1988 and the other in 2011, argued that Gould had overstated or misrepresented the case, and that Morton's measurements were essentially correct. In the latter study, entitled "The Mismeasure of Science: Stephen Jay Gould versus Samuel George Morton on Skulls and Bias" and authored by six anthropologists, it was concluded that the bias came from Gould, who failed to examine and remeasure the crania in order to determine Morton's level of accuracy. However, this study was reviewed in an editorial in "Nature", which recommended a degree of caution, stating "the critique leaves the majority of Gould's work unscathed," and noted that "because they couldn't measure all the skulls, they do not know whether the average cranial capacities that Morton reported represent his sample accurately." The journal stated that Gould's opposition to racism may have biased his interpretation of Morton's data, but also noted that "Lewis and his colleagues have their own motivations. Several in the group have an association with the University of Pennsylvania, and have an interest in seeing the valuable but understudied skull collection freed from the stigma of bias and did not accept Gould's theory "that the scientific method is inevitably tainted by bias."