Manufacturing Critical Path Time or (MCT) is the typical amount of time from when a customer creates an order, through the critical-paths required, until the first piece of that order is delivered to the customer.
“The typical amount of calendar time from when a manufacturing order is created through the critical-path until the first, single piece of that order is delivered to the customer.” MCT is a random variable and will likely fluctuate every time it is measured, thus there is generally no need to define MCT using a statistically significant sample as it is expected to vary over time. MCT must be measured in “real time “because that is how delivery is viewed by customers. Consequently, breaks in continuous operation, such as work weeks less than 7 days and work days less than 24 hours, do extend MCTs, but must be accounted for. Calendar time is generally measured in days.
MCT begins with the creation of an order by the customer. Consequently, delays between the customer order creation and the supplier order creation must be accounted for. MCT quantifies the longest critical-path duration of product-specific order fulfillment activities including: order processing, materials planning, scheduling, raw materials, manufacturing operations, logistics, and delays attributed to work-in-process and finish good inventories. MCT takes the perspective of the first piece of an order as is consistent with order fulfillment. MCT takes the perspective of a single piece of an order to ensure consistent measurement regardless or order size. MCT includes logistics time, which is of particular interest since it can be more difficult and expensive to expedite than the operational activities of MCT.
MCT ends when an order is delivered to a customer’s first point of receipt. This is typically a customer’s Receiving Department, but can vary depending on replenishment strategy.
Sourced: https://www.oskgpsc.net/supplierdevelopment/uploads/MM06_MCT_04-20-06.pdf