The "simple"/"obvious"/"clear" domain represents the "known knowns". This means that there are rules in place (or best practice), the situation is stable, and the relationship between cause and effect is clear: if you do X, expect Y. The advice in such a situation is to "sense–categorize–respond": establish the facts ("sense"), categorize, then respond by following the rule or applying best practice. Snowden and Boone (2007) offer the example of loan-payment processing. An employee identifies the problem (for example, a borrower has paid less than required), categorizes it (reviews the loan documents), and responds (follows the terms of the loan). According to Thomas A. Stewart,