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Electronic searches were conducted using PsycINFO and the Education Resources Information Center (ERIC), and these were supplemented with hand searches of major research journals, reference checks of past literature reviews, and nominations from leading experts in the field of early literacy. These search procedures yielded more than 8,000 potential articles that were screened to determine their relevance to the research questions and their consistency with all selection criteria established by the panel. This led to the identification of approximately 500 research articles that were used in the meta-analyses conducted by the panel.