Knowledge, usually research findings as found in a journal, research report, or similar document approved through a peer review process. Because of the potential widespread use or recognition of knowledge resources, they should generally be among the highest quality resources.

Product or tool includes, training materials, PowerPoint presentations, or publications that proscribe a specific process to follow or method to employ. Ideally, most products or tools in this category will have been reviewed externally and evidence will be provided that the product or tool has improved learning or achieved its goals.

Guidance, generally a written document that provides expert advice to improve instruction, is based on current theory or research; is state of the art knowledge; and has a substantial evidence base. The following would generally be considered guidance: congressional testimony, policy or issue briefs, field guides, fact sheets, criteria for good data use, criteria for high quality instruction.

Services include resources such as workshops, conferences, or expert technical assistance that are not practical for a peer review process, but that nonetheless are likely to be useful in helping states meet NCLB expectations. Services should include an evaluation component and have evidence of high quality such as established reputation of the source or use of materials based on rigorous evidence.