Most accounts of scientific and technological development stress the importance of quality judgments for particular technical fields. This study investigates social psychological and structural factors associated with such judgments for nineteen fields in nuclear waste and solar cell research. The results of the analysis indicate a tendency toward positive bias for fields in which researchers have been active, for this bias to be stronger in less innovative fields, and for elite membership to affect this bias in different ways depending on the nature of the system. In addition, there was no tendency for those with a high level of social contacts to others working in a field to display a positive bias, except in consensually innovative fields.