A common-size income statement is a type of financial statement that displays all the items in an income statement as percentages of sales or total revenue. Common-size statements are useful for comparing results between different years or across different companies, by providing an easy way to compare the size of each item to total revenue. The common-size statement shows easily how expenses, such as cost of goods sold, salaries, and other operating costs change relative to sales or total revenue. Analysts can use this information to identify changes and trends over time and make strategic decisions based on their findings.