Data extraction is the process of transcribing information from the primary studies under review using a standard form or template designed to capture all of the detail relevant to a synthesis or meta-analysis. To ensure accuracy, double data extraction is recommended. This is when two reviewers independently extract the data and then discuss any discrepancies that might occur.
Adapted from: Buscemi, N., Hartling, L., Vandermeer, B., Tjosvold, L., & Klassen, T. P. (2006). Single data extraction generated more errors than double data extraction in systematic reviews. Journal of clinical epidemiology, 59(7), 697-703. https://doi.org/10.1016/j.jclinepi.2005.11.010
The university library provides access to several books on meta-analysis and meta-synthesis including: