There is growing evidence that managers perceive the environment inaccurately and may not be aware of this inaccuracy, something referred to as knowledge (mis-)calibration. The performance implications of both inaccurate perceptions and lack of calibration remain largely unknown. Using survey data this paper reports high levels of perceptual error and some degree of overconfidence in the context of a single environmental issue. It is found that accurate perceptions are associated with performance. This paper tests whether strategic issue importance, as measured by resource dependency, influences this association but only limited evidence is found to support this. Knowledge calibration is not found to be associated with performance.