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Title / Use statistical process control tools for the control and improvement of processes
Level / 4 / Credits / 6
Purpose / People credited with this unit standard are able to: explain the purpose and uses of statistical process control; apply statistical process control tools to workplace situations; and interpret the results of statistical process control and take action.
Classification / Business Operations and Development > Quality Management
Available grade / Achieved
Explanatory notes
1This unit standard covers both process capability tools and process control charts as follows:
process capability tools – capability ratios, CPK, CP, SixSigma;
process control charts – X bar and R charts, X charts, P charts, C charts, CUSUMs.
2The credit value for this unit standard has been calculated on the basis that people seeking credit have acquired competence in the relevant statistical analysis skills.
3Assessment evidence for this unit standard must be collected from practical workplace experience related to quality improvement.
Outcomes and evidence requirements
Outcome 1
Explain the purpose and uses of statistical process control.
Evidence requirements
1.1Explanation matches the statistical process control tools with the requirements of the situation and the type of data required.
Rangedata – variable, attributes, fixed and variable sample size.
1.2Explanation of the distinction between product specifications and process limits establishes the valid uses of the tools.
1.3Explanation of how and when a process control study should be set up establishes the significance of previous process capability analysis.
1.4Explanation of patterns of variability, measures of central tendency and spread, and variability and causes of variation establishes their significance for and applications in process control.
Rangevariation – common and special.
Outcome 2
Apply statistical process control tools to workplace situations.
Evidence requirements
2.1Application of tools ensures the validity of the results.
Rangesampling frequency, target values.
2.2Charts are designed and constructed to meet the requirements of the situation, and ensure validity of interpretation.
Rangecontrol limits, sample size, selection of scale, use of historical data.
2.3Data is processed and/or plotted to the level of accuracy required for the situation.
Outcome 3
Interpret the results of statistical process control and take action.
Evidence requirements
3.1Interpretation of results identifies process characteristics required for decision making.
Rangecharacteristics – degree of capability or incapability, degree of control or out-of-control, degree of process stability, trends.
3.2Actions are taken on the basis of valid interpretation of results.
Rangeselection of process, adjustment of process, selection of process specifications.
Planned review date / 31 December 2019Status information and last date for assessment for superseded versions
Process / Version / Date / Last Date for AssessmentRegistration / 1 / 31 August 1996 / 31 December 2016
Revision / 2 / 7 September 1999 / 31 December 2016
Review / 3 / 22 September 2004 / 31 December 2016
Rollover and Revision / 4 / 18 July 2008 / 31 December 2016
Rollover and Revision / 5 / 17 November 2011 / 31 December 2016
Rollover / 6 / 18 April 2013 / 31 December 2018
Rollover / 7 / 16 April 2015 / N/A
Consent and Moderation Requirements (CMR) reference / 0113
This CMR can be accessed at
Please note
Providers must be granted consent to assess against standards (accredited) by NZQA, before they can report credits from assessment against unit standards or deliver courses of study leading to that assessment.
Industry Training Organisations must be granted consent to assess against standards by NZQA before they can register credits from assessment against unit standards.
Providers and Industry Training Organisations, which have been granted consent and which are assessing against unit standards must engage with the moderation system that applies to those standards.
Requirements for consent to assess and an outline of the moderation system that applies to this standard are outlined in the Consent and Moderation Requirements (CMR). The CMR also includes useful information about special requirements for organisations wishing to develop education and training programmes, such as minimum qualifications for tutors and assessors, and special resource requirements.
Comments on this unit standard
Please contact NZQA National Qualifications Services if you wish to suggest changes to the content of this unit standard.
NZQA National Qualifications ServicesSSB Code 130301 / New Zealand Qualifications Authority 2018