BS ISO IEC 33020:2015 pdf free download – lInformation technology – Process assessment – Process measurement framework for assessmentof process capability
4 overview
The capability to perform a process to a specific level of performance depends on well establishedprinciples. This International Standard sets out those principles that are common to all domains. Theprocess capability measurement framework described in this International Standard is expressed interms of a set of process attributes.Each process attribute is defined in terms of a set of process attributeoutcomes which can be evaluated to indicate the extent of achievement of the process attribute.Theprocess attributes are organised into process capability levels, ranging from lncomplete (in which theprocess does not achieve its defined process outcomes) to lnnovating (in which the processis continuallyimproved to respond to organizational change).
The result of an assessment,using a process assessment model that incorporates this processmeasurement framework, will be a set of process profiles – ratings of the achievement of the set ofprocess attributes for each process in the scope of the assessment. The result can also be expressedin terms of the capability level ratings achieved for each process in the assessment scope.A capabilitylevel rating does not guarantee that an organization will perform its processes at any given processcapability level, simply that it is capable of performing its processes at that level.
5.1 Introduction
This clause defines a process measurement framework for the assessment of process capability,conformant with the requirements of lSO/IEC 33003.This process measurement framework provides aschema that can be used to construct a process assessment model for assessing process capability.Within this process measurement framework, the measure of capability is based upon a set of processattributes.Each process attribute defines a measurable property of process capability. The extent ofprocess attribute achievement is characterised on a defined rating scale. The process capability levelfor an assessed process is derived from the set of process attribute ratings represented in the processprofile.
The achievement of one process attribute may be associated with the achievement of another processattribute within the process measurement framework.
5.5.1 One dimensional aggregation methods
Havingconverted the ordinalratingsto intervalvalues,one ofthe following one dimensionalaggregationmethods may be used to obtain a summary rating.
5.5.1.1 One dimensional aggregation using arithmetic mean
Aggregation may be performed by computing the arithmetic mean(average) of the ratings of the intervalvalues, rounding the result to the nearest integer (by rounding up or down), and converting the resultback to the corresponding ordinalrating. When rounding is necessary the interval value will be roundeddown to the nearest integer when the average value is less than the midpoint between consecutiveintegers; it will be rounded up if the average value is at or above the midpoint between consecutiveintegers.
5.5.1.2One dimensional aggregation using median
Aggregation may be performed by computing the median (middle value) of the ratings of the intervalvalues, the given data is arranged in order from lowest to highest. If there is an odd number of datathen the median is the middle value. If there is an even number of data then the two middle values areselected and the arithmetic mean (average) taken.If there is an even number of ratings and the processof taking an average of the two middle values results in real number, then the number is rounded to aninteger value using the rules above.
NOTE The operation of taking the mean is mathematically valid since we are dealing with interval data.