An efficiency ratio that measures how many days a company can operate without having to access non-current (long-term) assets. The defensive interval ratio (DIR) is calculated as:DIR = Current Assets / Daily Operational ExpensesAlso known as the "Defensive Interval Period". |||The DIR is thought by many people to be a better liquidity measure than the quick and current ratios. Because these ratios compare assets to liabilities rather than comparing assets to expenses, the DIR and current/quick ratios would give quite different results if the company had alot of expenses, but no debt.The DIR is not a replacement to the other ratios, but a complement. As with all financial analysis, a prudent investor will use a basket of different analysis when deciding on whether a company is a good investment.