Internal customer is a buzzword used in management, popularized by Joseph M. Juran
He defined an internal and external customers as anyone affected by the product or by the process used to produce the product, in the context of quality management. Internal customers may play the role as supplier, processor, and customer in the sequence of product development.
He claimed that the organization must understand and identify both internal and external customers and their needs. The organization must focus on its primary task of satisfying the customer’s requirements and expectations.
If one department, individual or process within an organization supplies another such within the same organization with goods, information or services then the latter is described as the internal customer of the former.
For example, a dispatch department may be the internal customer of a packing department, which in turn may be the internal customer of the manufacturing process. Juran advocated 'exceeding the customer's expectations.'
When misapplied, this concept can and does confuse the metric being studied with the complete collegial and bilateral relationship of employees working together, serving the goals of the company.
True customers have complete discretion over spending, and unilaterally select when where how and with whom they will do business. So the 'Internal Customer' analogy has limited utility to colleagues and is prone to misapplication.
When companies misapply the important metric of 'customer satisfaction', to colleagues, they run the risk of trying to satisfy the 'internal customer' (some employees and not others) instead of satisfying the goals of the company.
EG: An end user likes downloading free but dangerous screen savers, and downloads viruses, and then the IT Dept. removes the screen savers and 'displeases' the 'internal customer.' In this example the misapplication of 'customer satisfaction' of the 'internal customer' risks the integrity of the computer system, enforcement of company policy and worker productivity for the misapplied concern of pleasing the (internal) customer.