Overview
The Quality Planner uses inspection characteristics to define the items to be inspected and the specifications for the inspection. From a technical standpoint, the Planner assigns one or more characteristics to each inspection operation. The figure displays the data that the Quality Planner manages:

The Quality Planner maintains the following information:
Characteristic type: Is the characteristic quantitative (for example, length or weight) or qualitative (for example OK/NOK, or packaging material)?
The control indicators affect the further processing of the inspection characteristic. For a detailed explanation, refer to the SAP Help Portal.
Does the planner use a master inspection characteristic (MIC)? If so, data from the MIC is copied or referenced. We address this in the next section.
The characteristic text informs the Quality Technician what to inspect or measure.
The Planner can create short and long texts in different languages for the master inspection characteristic. The language in which the master inspection characteristic is displayed in the task list depends on how it was integrated (referenced or copied). Only in referenced master inspection characteristics are short and long texts displayed according to the user's logon language.
The system uses the sampling procedure to calculate the sample size and during result valuation. For example, the Quality Planner assigns a fixed sample size of 5 PC and an acceptance number of 1. During result recording, the Quality Technician inspects 5 PC. If there is one or fewer defect items, the system accepts the characteristic. Note that you must enable the use of a sampling procedure in the characteristics control indicator. If you don't assign a sampling procedure, the system uses the plant's default value from customizing or, if no default exists, a 100% inspection.
If the Quality Technician needs equipment or tools to measure a characteristic, the Quality Planner assigns the equipment here. Note that, as a prerequisite, the equipment or tool must also be assigned at the operation level and a respective control indicator must be active.
If you want to use dynamic modification at the characteristic level, the Quality Planner defines the dynamization parameters for the characteristic.
When measuring a characteristic, the Quality Technician must use a specific inspection method. In this case, the Quality Planner assigns the inspection method to the characteristic. The inspection method must be available in the system as a master record and cannot be created directly in the inspection plan.
To assign attributes for qualitative characteristics, the Quality Planner uses catalogs. Additionally, they predefine the code of the defect that the system generates when the characteristic is rejected. It is important to note that automatic defect creation must be enabled in the characteristics control indicator.
Using Reference Characteristics or Incomplete/Complete Copy Models
After reviewing the guidelines provided, apparently the Quality Planner is responsible for making various manual settings to define an inspection characteristic. However, to simplify and standardize the process of defining an inspection plan, SAP suggests avoiding the direct definition of characteristics within the plan. Instead, it is recommended that the Quality Planner use master inspection characteristics (MIC) within the inspection plan whenever feasible. The options available to the Planner will depend on whether the MIC is a reference characteristic or an (in)complete copy model:

If the MIC is a reference characteristic, the Planner references it in the plan. At this point, the MIC cannot be changed. Any changes made to the MIC master data (for example codes of characteristic attributes, tolerance limits, and so on) are automatically applied to the inspection plan. When the Planner references a master inspection characteristic, the system automatically chooses the current version of the master inspection characteristic.
A typical example of this is the packaging material. Regardless of the material being shipped, your company uses plastic foil, wood wool, or paper cutting for all packaging purposes. To implement this scenario, the Quality Planner defines one qualitative MIC and assigns a selected set that includes plastic foil, wood wool, paper cutting, and no packaging material as possible attributes. When defining the goods issue inspection, the Quality Planner references the MIC in all inspection plans for goods issue. If you decide to no longer use plastic foil, the Quality Planner can change the MIC and assign a different selected set without the entry for plastic foil. Since the characteristic is referenced, the change will automatically be applied to all inspection plans that use the MIC.
If the MIC is an (in)complete copy model, the Planner copies the master data settings from the MIC into the inspection plan. They then modify the characteristic to align with the inspected material or other business requirements. When changing the MIC, the changes are not automatically applied to the inspection plan.
A practical example is the length of a material: Since the length depends on the material being manufactured, the Planner cannot predefine the length in the MIC. When assigning the MIC to the task list (which also applies to a material), the Planner knows the target length and the allowed tolerances. If the tolerance values change, for example, due to a change in the manufacturing process, the task list must be adjusted.
Note that in both cases, the respective MIC must have been released before they can use it in an inspection plan.
By utilizing predefined MICs in inspection plans, not only is the plan's definition made easier, but it also simplifies the evaluation of inspection results for the Quality Engineer. The Quality Engineer can analyze the history of inspection results at the MIC level using the Result History app.
If the Quality Planner wants to obtain an overview where they used a specific MIC, the SAP S/4HANA system offers a where-used list for master inspection characteristics.
Note
If you don't want to define MICs or if you're unable to standardize your inspections for a business reason, the Quality Planner can also create inspection characteristics directly in the inspection plan. This approach is flexible because it allows users to define the characteristic directly where they need it. However, users cannot reuse a characteristic defined in one plan in another inspection plan.
Furthermore, analyzing the result history on inspection characteristic level is more cumbersome compared to performing the analysis on the MIC level. Another disadvantage of defining characteristics directly in an inspection plan is the high manual effort required (→ you must make all settings in the plan) and the high probability for errors (→ typos or incorrect settings).
Calculated Inspection Characteristics
Consider a situation where a desired value can't be directly measured, and other characteristics must be measured and used to calculate the intended value. SAP S/4HANA provides calculated inspection characteristics to implement this scenario. The following image illustrates an example of a calculated inspection characteristic:

In the example, the characteristic of interest is the volume of a cylinder (characteristic 30). As you cannot easily measure the cylinders volume directly, the Quality Planner instructs the Quality Technician to measure the cylinders diameter (characteristic 10) and height (characteristic 20), respectively. By using the diameter and the height, it is easy to calculate the cylinders volume using the displayed formula. The formula is as follows:
1Volume = (Single value of characteristic 10 * Single value of characteristic 10) * π/4 * (Single value of characteristic 20)
The formula uses A0 to represent the measured value of a single unit. The SAP S/4HANA system offers more standard parameters, such as the arithmetic mean of multiple measured values and the variance of multiple measured values. For complex calculations, your Application Consultant and Developer can define function modules if needed.
Note
The Application Consultant defines the parameters for the calculated inspection characteristic in Customizing: Quality Management → Quality Inspection → Results Recording → Define Parameters for Calculated Characteristics.
To flag a characteristic as calculated characteristic, the Quality Planner specifies this in the control indicator for the inspection characteristic. They then assign a corresponding formula in the detail screen of the inspection characteristic. In the formula, you can use mathematical standard functions and numerical values.
Note
You can only calculate inspection results for inspection characteristics within one operation.
Conditional Inspection Characteristics
Imagine a situation where you must conduct a functional test on a device. Only if the initial test is successful, you can proceed with a more thorough inspection and measure additional characteristics. SAP S/4HANA provides a solution for this scenario called Conditional Inspection Characteristics. The image below illustrates an example of a pump:

In the inspection plan, the Quality Planner specifies that the Quality Technician should initially conduct a functional test of the pump (CH 10). If the test is successful, they should then proceed to measure the power consumption (CH 20) and pressure (CH 30) of the pump. In the event of a failed functional test, the Quality Technician should document the type of defect as an attributive inspection characteristic (CH 40).
During results recording, the system locks three characteristics (20, 30, and 40) until the Quality Technician records an inspection result for the functional test (CH 10) and valuates the result. Depending on the result valuation (→ accepted or rejected), the system activates either the characteristics power consumption and pump pressure (for functional test accepted) or the characteristic type of defect (for functional test rejected).
Note
The inspection of conditional inspection characteristics (After Acceptance, After Rejection) generally depends on the results of the previous required inspection characteristic within the same operation. The Quality Planner defines in the control indicators for the inspection characteristic whether a conditional inspection characteristic is activated after the lead characteristic is accepted or rejected. For example, if the lead characteristic is accepted, the Quality Planner may activate a conditional inspection characteristic for further inspection.
Changes to the Inspection Plan
Changes to inspection plans are documented and can therefore be traced. The following image shows an example:

In the example, the Quality Planner wants to know all changes to a specific plan. After performing the selection, the system displays the task list changes (when using the app Display Inspection Plan Changes) or the related change documents (when using the app Inspection Plan Display Change Documents).
In the list of results, you see, for example, that the materials T-BQ125 and T-BQ225 were assigned to the task list header on 23.02.2023.
Hint
Changing and especially keeping track of changes to inspection plans can be cumbersome. The SAP S/4HANA system offers the objects change master and change record to implement changes to an inspection plan in a compliant manner. Please refer to the Application Documentation for additional information.