What is a Key Process Input or Output variable (KPIV)?

Key process input or output variable (KPIV) refers to various factors that can cause an impact during the production process. Once the key process input variables for a process are determined, statistical experiments can be designed that can reveal optimal values for each factor to achieve the desired output quality.

How to use a Key Process Input or Output Variable

Factors within a process correlated to output characteristics(s) are important to the internal or external customer. Optimizing and controlling these is vital to the improvement of the KPOV. A good example is income variability, income is an independent variable because it causes and influences another variable consumption. Income (KPIV) will determine the quality of a commodity bought or the service given out which is the (KPOV).

We can also have another example of a company that looks to increase profit margins on t-shirts by using a cheaper fabric supplier, would evaluate the projects success depending on whether customers continued to buy them, or if sales decreased due to poor satisfaction. The end-goal profit margins, number of sales, and customer complaints are examples of output variables (KPOV), whereas the decision to change suppliers is an example of the input variable (KPIV).The main point here is finding the good KPIV that will lead to a significant production of KPOVs in a system or in a company. 

Therefore, Design of experiments (DOE) can be used to find out the impacts of KPIV and KPOV co-relation in the final results of certain changes of variables in a system or a process.Examples of KPIV:

•  The type of fabric
•  The quality of the fabric
•  The price if the fabric
•  The cost of making the t-shirts