Definition of 'Horizontal Audit'
An evaluation of one process or activity across several groups or departments within an enterprise. A horizontal audit is appropriate for processes and activities that are similar across a number of functional groups in a company, in order to assess the effectiveness of the common approach.
Also known as a "peer audit."
Investopedia explains 'Horizontal Audit'
A horizontal audit assesses the same process across different groups or departments, while a vertical audit assesses all the activities in a given department. Horizontal audits may be appropriate for such things as employee training and internal controls. It is not uncommon for both auditing approaches to be used when examing a company's or department's overall business.