The report presents the method and findings from a thematic analysis using IN-SPIRE™ to identify re-occurring strength, weakness, and recommendation themes from over 42,000 individual reviewer comments for 1,521 R&D projects. Themes are topics, ideas, and patterns of meaning that come up repeatedly in reviewer comments. The compiled reviewer comments cover projects across five EERE R&D offices are (AMO, BETO, HFTO, VTO, and WPTO) from 2015-2019. The projects examined include EERE-funded financial assistance, SBIR, and different national laboratory projects. The analysis found 64 strength, weakness, and recommendation themes across the five review criteria –Accomplishments, Approach, Collaboration/Coordination, Relevance, and Proposed Future Work. The themes identified will be helpful to EERE R&D managers and can inform their decisions about their future projects. Knowing the strengths and weaknesses of previous projects can provide EERE R&D managers with information that extends beyond their own experiences to guide future projects towards success and steer them away from failure. The report also identifies opportunities to further improve the EERE peer review process.