Secondary evidence according to the legal view is acceptable if primary evidence the strongest evidence, e.g., original documents) has been destroyed or is not reasonably procurable. Secondary evidence must be a proper representation of primary evidence, e.g., copies of a contract.

Under peak-load pricing, prices vary directly with capacity usage. Thus, when demand falls and idle capacity is available, the price of a product or service tends to be lower.

An economic indicator is highly correlated with changes in aggregate economic activity. A leading indicator changes prior to a change in the direction of the business cycle. The leading indicators included in the Conference Board's index are average weekly hours worked by manufacturing workers, unemployment claims, consumer goods orders, stock prices, orders for fixed assets, building permits, timeliness of deliveries, money supply, consumer confidence, and the spread between the yield on 10-year Treasury bonds and the federal funds rate. An increase in weekly hours worked by production workers is favorable for economic growth.