School psychologists are the primary professional responsible for conducting evaluations for special education eligibility. This evaluative process involves the complex synthesis of various sources of data. A vast amount of research shows humans are susceptible to making cognitive errors within their decision making, with a confirmation bias being one of the most prevalent. Previous research on the use of a confirmation bias in special education evaluations found divergent results. One of the main hypotheses for this divergence in results was the difference in data ambiguity across studies. The purpose of this study was to investigate the impact of data ambiguity on the use of a confirmation bias in a psycheducational analogue study. Participants reviewed an analogue study that varied by referral concern (Descriptive or Non-Descriptive) and assessment results (Average, SLD, or Ambiguous). All other information was kept constant across participants. Each participant provided an eligibility hypothesis, rated the importance of pieces of data on their decision making, provided ratings of confidence, and responded to questions regarding their use of common cognitive heuristics. Results showed school psychologists within this study utilized data appropriately across both referral types; no confirmation bias was present. Similar decisions were made in regard to eligibility, confidence, and importance placed upon data no matter which referral was given. These results provide evidence school psychologists are capable of adequately processing psychoeducational vignettes of varying complexity, and coming to similar decisions. It also provides evidence school psychologists are able to protect against the use of a confirmation bias based upon referral information.