Being aware of the type of methodology used in a study is an important part of the research process. Many indexes -- such as PsycINFO -- provide limits to restrict your search results by methodology type.
A meta-analysis is a statistical analysis that combines the results of multiple scientific studies. Further further reading on the differences between systematic reviews and meta-analyses, see Garg et al.'s "Systematic Review and Meta-analysis: When One Study Is Just not Enough" CJASN January 2008, vol. 3 no. 1, 253-260. Another 'must read' article on the benefits of systematic reviews and meta-analyses as they pertain to organizational behavior is Kevin Daniels' "Guidance on conducting and reviewing systematic review (and meta-analyses) in work and organizational psychology" EJWOP November 2018.
For definitions of each methodology, visit the following APA Databases Methodology Field Values webpage.
For the purposes of MIR-850, Dr. Lilius has provided a list of research methodology types, arranged in descending order of strength. To summarize, the more meta-analyses and systematic reviews you identify to support your case, the better. Bear in mind that the number of systematic reviews (or meta-analyses) available on a specific topic may be scant so you may need to broaden your search.
In the library session you will be shown how to limit your searches to include only results that adopted a particular methodology.