Research has been conducted to identify and analyze how schools are determining that the activities of their Professional Learning Community (PLC) are directly tied to student achievement as there is currently a gap in the existing literature with regards to this topic. For the purpose of this study, a "successful" PLC was defined as one whose activities have been proven to have a positive impact on increasing student achievement (DuFour, 2004). The following research questions guided this study: (a) how are schools determining that student achievement success is related to the activities of the PLCs? and (b) what are the varieties of ways PLCs are using data to improve student achievement? The research design was a qualitative meta-analysis of a sample of 42 studies. An interview protocol of five questions was used to collect the data from the sample. Four themes emerged from this meta-analysis: (a) participating in PLCs leads to adult learning, (b) participating in PLCs leads to changes in teaching practice and teaching culture, (c) strength of PLC characteristics is related to student achievement, and (d) presence of student advisories as an intervention protocol in successful PLCs. The following recommendations were made based on the study's findings: (a) research that examines how teaching practices change as a result of participation in PLCs, (b) quantitative research that tests the findings of this study, (c) conduct research with a sample that includes empirical data derived from dissertations regarding PLCs and student achievement, as their findings can potentially add to the body of knowledge regarding the topic. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]