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Rating method R3
Process attribute rating across assessed process instances shall be made without aggregation.
In principle the three rating methods defined in ISO/IEC 33020:2019 depend on
a) whether the rating is made only on process attribute level (Rating method 3 and 2) or – with more level of detail – both on process attribute and process attribute outcome level (Rating method 1); and
b) the type of aggregation ratings across the assessed process instances for each process
If a rating is performed for both process attributes and process attribute outcomes (Rating method 1), the result will be a process performance attribute outcome rating on level 1 and a process attribute achievement rating on higher levels.
Depending on the class, scope and context of the assessment an aggregation within one process (one-dimensional, vertical aggregation), across multiple process instances (one-dimensional, horizontal aggregation) or both (two-dimensional, matrix aggregation) is performed.
ISO/IEC 33020:2019 provides the following examples:
When performing an assessment, ratings may be summarised across one or two dimensions. For example, when rating a
process attribute for a given process, one may aggregate ratings of the associated process (attribute) outcomes – such an aggregation will be performed as a vertical aggregation (one dimension).
process (attribute) outcome for a given process attribute across multiple process instances, one may aggregate the ratings of the associated process instances for the given process (attribute) outcome such an aggregation will be performed as a horizontal aggregation (one dimension)
process attribute for a given process, one may aggregate the ratings of all the process (attribute) outcomes for all the processes instances – such an aggregation will be performed as a matrix aggregation across the full scope of ratings (two dimensions)
The standard defines different methods for aggregation. Further information can be taken from ISO/IEC 33020:2019.
The process capability level achieved by a process shall be derived from the process attribute ratings for that process according to the process capability level model defined in Table 19.
The process capability level model defines the rules how the achievement of each level depends on the rating of the process attributes for the assessed and all lower levels.
As a general rule the achievement of a given level requires a largely achievement of the corresponding process attributes and a full achievement of any lower lying process attribute.
Scale | Process attribute | Rating |
Level 1 | PA 1.1: Process performance process attribute | Largely |
Level 2 | PA 1.1: Process performance process attribute PA 2.1: Process performance management process attribute PA 2.2: Work product management process attribute | Fully Largely Largely |
Level 3 | PA 1.1: Process performance process attribute PA 2.1: Process performance management process attribute PA 2.2: Work product management process attribute PA 3.1: Process definition process attribute PA 3.2: Process deployment process attribute | Fully Fully Fully Largely Largely |
Level 4 | PA 1.1: Process performance process attribute PA 2.1: Process performance management process attribute PA 2.2: Work product management process attribute PA 3.1: Process definition process attribute PA 3.2: Process deployment process attribute PA 4.1: Quantitative analysis process attribute PA 4.2: Quantitative control process attribute | Fully Fully Fully Fully Fully Largely Largely |
Level 5 | PA 1.1: Process performance process attribute PA 2.1: Process performance management process attribute PA 2.2: Work product management process attribute PA 3.1: Process definition process attribute PA 3.2: Process deployment process attribute PA 4.1: Quantitative analysis process attribute PA 4.2: Quantitative control process attribute PA 5.1: Process innovation process attribute PA 5.2: Process innovation implementation process attribute | Fully Fully Fully Fully Fully Fully Fully Largely Largely |