This document presents a study on using relevance feedback to improve information retrieval-based concept location in software engineering. The study uses an IR tool with the Lucene engine and Rocchio algorithm for relevance feedback. It evaluates the tool on bug reports from Eclipse, jEdit, and Adempiere, measuring the number of methods investigated before finding the target method with and without relevance feedback. The results show relevance feedback improved concept location in most cases by reformulating queries based on developer feedback on result relevancy. Future work includes more experiments and automatically calibrating parameters.