This chapter reflects meta-analysis in order to produce comparable results and significant update on the cognitive functioning and awareness of illness in schizophrenia. The five cognitive domains (total cognition, IQ, memory, executive function, and Wisconsin Card Sorting Test (WCST)) were defined as in Aleman et al. The meta-analysis provides a comprehensive overview and summary of research into the relationship between insight and neurocognition in psychosis. The meta-analysis first considers possible methodological reasons for results, and second, the implications these findings have for a "neurocognitive theory of insight". Meta-analysis is a powerful tool in quantitative research; however, there are a number of limitations, which should be considered when interpreting results. A review and meta-analysis by Alvarez & Emory demonstrates that common tests such as the WCST or Stroop do not simply localize as frontal lobe tests. The neurocognitive theory is more applicable to certain populations as opposed to 'psychosis' in general.