Accounting and reviews involve of the preparation of financial statements with a reasonableness review. This activity is a considerably more complicated and responsible procedure than compilations, requiring more accounting knowledge. Auditing consists of correcting the financial statements resulting from the accounting processes and of rendering a professional opinion attesting to the reliability of the financial statements. It is the ability to attest to the reliability of financial information which most distinguishes the CPA from other professions. This audit activity takes up the majority of time in national CPA firms.
Accountants serve a dual function regarding taxes.
Although national firms devote a significant amount of time to tax matters, local firms allocate even more, mostly for the preparation of the actual tax returns. Public accounting firms offer a number of management consulting services to their clients. The scope and number of these special services have increased significantly since the 1980s. Accounting firms consult in areas that fall within their expertise and which the client firms themselves are not equipped to handle adequately. As expected, the large national CPA firms have broader areas of expertise than do the smaller local firms that offer broad financial planning advice to small firms without the highly specialized personnel typically on the payrolls of larger firms.