Use the P-Diagram
(Parameter Diagram) to identify and catalog the sources of variation in a
system.
The P-Diagram provides a visual representation of how various factors affect system performance. You can use this information to optimize performance, improve the design of the system, mitigate risk, communicate design requirements, and create better quality control.
The P-Diagram answers the following questions.
- What are the external factors that influence system performance?
- How do inputs, outputs, noise factors, and control factors interact with one another?
- Which parameters can you control, adjust, or optimize to achieve the desired performance?
- What can you do to mitigate potential failure modes?
How-to
- To the center table, enter a description or insert an image of the system to evaluate.
- To the surrounding tables, catalog your parameters by adding them to the
appropriate tables. To add rows, hold the mouse pointer on the column, click
the add button
, choose
Add Row, and then enter a parameter. - Inputs
- The input parameters (x variables) that provide the necessary materials, data, or energy to the system, for example, initial conditions, material properties, customer specifications, or energy requirements.
- Noise Factors
- The input parameters (x variables) that are uncontrollable or unpredictable, for example, ambient environmental conditions, unplanned downtime, supplier variability, operator performance variability.
- Control Factors
- The input parameters (x variables) that you can intentionally change, for example, machine or process settings, time constraints, or material choices.
- Outputs
- The output parameters (y variables) that represent the desired outcomes, product characteristics, or performance metrics of the system, for example, quality, efficiency, or customer satisfaction.
- Errors
- The potential failure modes, deviations, or defects that can result from the system, for example, discrepancies between expectations and reality, non-compliance with customer specifications, or operator mistakes.
- (Optional) Expand Interactions and use the tables to identify any positive or negative interactions. For
each pair, choose the interaction type.
- + Positive means that as one factor increases, the other increases too; or, as one factor decreases, the other decreases too.
- – Negative means that as one factor increases, the other decreases; or, as one factor decreases, the other increases.
For more information, go to Add and complete a form.
