This post explores feedback and feed forward approaches to improve development experiences in new product development (NPD).

This post was inspired by a new appreciation of the feedback and feed forward labels in John Boyd’s OODA loop sketch of 1995.

OODA Loop sketch that includes feedback, feed forward, and implicit guidance & control. Created by Mark A Hart. Based on a 1995 sketch by John Boyd.

A more common and older use of the phrases feedback and feed forward is from the design of control systems for mechanical and electrical devices.

To prepare for sharing these insights relating to new product development, I will review simplified electrical circuits that can be used to control the temperature in an electrical, tank-type appliance used to heat and store hot water.

Initial Design of a Water Heater

An initial system design includes a tank to store hot water. It includes a heater in an insulated tank. It includes a switch to activate the heater and a sensor to measure the water temperature. The water temperature is regulated by turning the heater switch on and off.

An initial design for an electrical, tank-type appliance used to heat and store hot water

A more sophisticated design would permit a user to input a set point for the desired water temperature. Ideally, the system would provide water at the set point temperature regardless of how much water was used for any task.

A Feedback Approach to Controlling Temperature

When a feedback approach is implemented, the temperature of the water exiting the tank is measured and that information is used to control the heater circuit.

A feedback approach to controlling the temperature of a water heater

This type of control is a feedback approach because the temperature sensor is after the circuit element producing the heat.

Feedback is an approach that uses information about current results to influence operation in the present. It includes modifications to a system based on results. Feedback produces a reactive response. This approach may be referred to as closed-loop feedback.

For this design, there is a characteristic lag (a delay after hot water is depleted before the heater is activated to raise the water temperature) and overshoot (a condition caused by exceeding the temperature set point because of a delay in deactivating the heater). An unsophisticated control circuit can not distinguish a scenario when a small amount of water is used or when a significant amount of water is used.

A Feed Forward Approach to Controlling Temperature

One implementation of a feed forward approach senses the amount of cold water entering the tank. The heater is turned on as a function of the amount of cold water entering the tank. This approach uses knowledge about the system to predict how much additional heat will be required. Such an approach is proactive.

A feed forward approach uses knowledge about the system to transmit a controlling signal from a source to a destination

Feed forward is an approach that uses knowledge about the system to transmit a controlling signal from a source to a destination. A feed forward approach is a rules-based approach.

Simultaneous Control Systems

A feed forward approach should be used with a feedback system. These are complementary approaches. The combination provides a system that is more responsive and more effective.

There are examples of analogous approaches in new product development.

Feedback Approaches in New Product Development

During new product development, it is common to present product prototypes to potential customers and gather feedback. Prototypes can take the form of surveys, A/B tests, and other interactions with hardware, software, and concepts.

This approach may be associated with other popular phrases such as ‘fail fast’ or ’safe to fail experiments’ where learning follows the development of a prototype. Another popular version of this type of approach includes the concept of a minimum viable product (MVP).

Feedback approach[...]