Quality in the process
A quality process has the right inputs and performs the right actions to produce outputs that meet the needs of customer processes.
Definitions of quality thus include:
· Fitness for purpose
· Right output, right time, right place
· Customer satisfaction
The Entry-Task-Validation-Exit (ETVX) model views processes within the context of:
1. Input or triggers
2. Tasks (also called Procedures)
3. Controls
4. Constraints
5. Output
There are four places where the quality can be specified and checked:
· Entry criteria define what inputs are required and what quality these must be to achieve the exit criteria. Entry criteria should be communicated to supplier processes, to become their exit criteria. If supplier processes are sufficiently well controlled, then there is no need to check inputs.
Entry Criteria: Inputs or Triggers: Processes are initiated by either inputs or triggers. An input is usually an output from a preceding process; a trigger is an event that invokes the process. In either case, in input or trigger, an associated list of entry criteria must be satisfied in order for the process to commence.
· Task definitions specify the actions within the process.
Tasks (also called procedures) are the action components of a process. In the ETVX model tasks follow a sequence that has a validation step. This step ensures that the process does not pass its output to another process or terminate until all exit criteria have been satisfactorily met.
· Validation definitions identify test points within the process and define the tests and criteria for checking at these points. This enables problems to be caught close to their cause, reducing rework and scrap costs, and enabling problem causes to be addressed.
This is a process checkpoint that occurs after the task(s) associated with the process have been completed. This checkpoint is also known as quality gate – its purpose is to ensure that the task(s) have produced an output that meets specifications and/or requirements of the process. A failure at the validation checkpoint generally requires re-performing the process tasks.
· Exit criteria define what outputs are required and what quality these must be to meet the needs of customer processes. Exit criteria may be derived from the entry criteria of customer processes.
All conditions that must be present and/or satisfied before a process can successfully terminate. Closely coupled to exit criteria is the output of the process itself. i.e, what the process was designed to produce. All processes produce an output.
· Controls: Process controls are limits that have been purposely placed on the process to prevent undesirable outcomes. Example include:
Policies
Checkpoints
Audits and integrity checking (i.e. cyclic redundancy checks, etc)
Error detection and correction processes.
· Constraints: Limitations imposed on a process are called constraints. Example include technical capabilities, available time frames, resources, transmission speeds, etc.
The key difference between a control and a constraint is that a control is designed into the process to produce or effect a desirable outcome, while a constraint is a limitation to the process (or environment) that may impact on the effectiveness and/or efficiency of the process.
Together, these make up what is known as the ETVX model (as below), which can be used to define the process and the quality required within it completely.
Fig. 1. The ETVX model
In process improvement, it can be useful to apply this model to processes that are suspected of being troublesome, in order to identify measures to identify specific problems.
