A number of factors will determine the size of a business, including its revenues, assets and earnings. Calculating total revenues over time is a good way to determine revenue. Financial statements like income statements and balance sheets are usually used. Assets are the physical and intangible assets owned by an organization. They can include intellectual property, property or other intangibles. Finally, income refers to the amount of money made after all expenses have been taken into account; this is usually calculated using the profit & loss statement.
You can tell if the company is expanding or contracting by looking at revenue and profits over time. It is possible that if there is an increase, it could indicate the business is doing well. However, if it decreases it might suggest it has difficulty competing with other businesses in that market. The management can get a better idea on the success of their operation by evaluating this data.