In general various approaches to consulting can be thought of as lying somewhere along a continuum, with an 'expert' or prescriptive approach at one end, and a facilitative approach at the other. In the expert approach, the consultant takes the role of expert, and provides expert advice or assistance to the client, with, compared to the facilitative approach, less input from, and fewer collaborations with the client(s). With a facilitative approach, the consultant focuses less on specific or technical expert knowledge, and more on the process of consultation itself. Because of this focus on process, a facilitative approach is also often referred to as 'process consulting,' with Edgar Schein being considered the best-known practitioner. The consulting firms listed above are closer toward the expert approach of this continuum.
Many consulting firms are organized in a matrix structure, where one 'axis' describes a business function or type of consulting: for example, strategy, operations, technology, executive leadership, process improvement, talent management, sales, etc. The second axis is an industry focus: for example, oil and gas, retail, automotive. Together, these form a matrix, with consultants occupying one or more 'cells' in the matrix. For example, one consultant may specialize in operations for the retail industry, and another may focus on process improvement in the downstream oil and gas industry.
Management consulting refers generally to the provision of business services, but there are numerous specialties, such as information technology consulting, human resource consulting, virtual management consulting and others, many of which overlap, and most of which are offered by the larger diversified consultancies. So-called "boutique" consultancies, however, are smaller organizations focusing upon one, or just a few of, such specialties.
The 1990s saw an increase in what has been termed a 'future-based' approach. This emphasised language and alignment of people within an organization to a common vision of the future of the organization, as set out in the book "Three Laws of Performance". The essential concept here was that the way people perform is seen to correlate to the way that world occurs for them, and that future-based language could alter the way the future actually occurs for them. These principles were increasingly employed in organizations that had experienced a market transition or a merger requiring the blending of two corporate cultures. However, towards the end of the 1990s the approach declined due to a perception that the concept outlined in this book did not in practice offer added value to organizations.