Criteria for the design and selection of literacy and thinking tools that allow educators to justify what they do are described within a wider framework of learning theory and research into best practice. Based on a meta-analysis of best practice, results from a three year project designed to evaluate the effectiveness of a secondary school literacy initiative in New Zealand, together with recent research from cognitive and neuro-psychologists, it is argued that the design and selection of literacy and thinking tools used in elementary schools should be consistent with (i) teaching focused (ii) learner focused, (iii) thought linked (iv) neurologically consistent, (v) subject specific, (vi) text linked, (vii) developmentally appropriate, and (viii) assessment linked criteria. Key words: Literacy, thinking, tools, justifying criteria.