We have recently undertaken a large-scale Systematic Literature Review (SLR) of a research question concerning the Technology Acceptance Model (TAM). At the end of the study, we observed some anomalies during the analysis of the extracted data. In our attempts to identify the cause of the anomalies, we found a number of mistakes that had been made during the data extraction process. We discuss each of the mistakes in terms of why they occurred and how they might have been avoided. We suggest a number of ways in which the available guidelines for conducting SLRs should be amended to help avoid such problems occurring in future reviews.