AIAG VDA SPC - Yellow Volume, a draft version for review.

Introduction

Statistical Process Control (SPC) has been used in industrial processes for decades - with varying degrees of success ;-)

In the automotive industry and many other sectors, one of the most commonly used SPC standards is the so-called AIAG SPC - a reference manual developed by the Automotive Industry Action Group. It is a widely recognized document that provides a wealth of valuable information on how to apply SPC, how to maintain control charts, and how to calculate process capability indices Cp, Cpk, process performance indices Pp, Ppk and many other topics.

Some organizations, especially those associated with the German automotive industry, followed VDA 4 requirements and their own guidelines — largely based on ISO 22514, ISO 3534, and ISO 7870.

These differences in applied standards caused (and still cause) occasional and unnecessary misunderstandings regarding terminology and methodology.

In February 2026, the Automotive Industry Action Group (AIAG) and the Verband der Automobilindustrie (VDA) jointly published the AIAG & VDA SPC "Yellow Volume"[1].

The "Yellow Volume" is VDA's way of releasing a document for public review and comment prior to final publication. The feedback phase for this document is open until May 3, 2026[2]. This means the final version of the standard is still being refined.

Now is the time to understand what's coming.

Scope of AIAG & VDA SPC

The scope of AIAG & VDA SPC is very broad - the manual covers the entire automotive supply chain[1]. The document addresses topics such as:

• Terms and definitions
• The concept of SPC, continuous improvement, and PDCA
• Requirements for SPC Applications
• Overview of Methods (i.e. Nelson Rules)
• Machine performance Pm, Pmk (equivalent of machine capability Cm, Cmk)
• Process capability Cp, Cpk
• Process performance Pp, Ppk
• Control charts
• Application of Software
• Documentation and Reporting
• Traceability and Archiving

Selected Aspects of AIAG & VDA SPC

Below is a subjectively selected set of key aspects covered by the draft AIAG & VDA SPC manual:[1]

• Terms and definitions. This is a critical aspect in industry, especially in international B2B relationships. Misunderstandings arising from the use of different definitions are a source of many issues. Therefore, it is always worth having a thorough understanding of each term's meaning.
• Roles and competencies. The manual explicitly defines the responsibilities of quality planning experts, product engineers, process engineers, and production operators within the SPC implementation framework.
• Machine performance Pm, Pmk. The new document introduces Pm/Pmk indices instead of the commonly used Cm/Cmk, because the short-term nature of machine capability testing means little understanding of stability, and it's safer to report results as Performance than Capability. This new approach is consistent with ISO 22514.
• Process capability over time. The new manual presents the application of capability indices in the following sequence: first, when qualifying a machine, we calculate its machine performance index Pm/Pmk; then, during process qualification, we assess the preliminary process performance Pp/Ppk; finally, after the start of series production, we continuously monitor the process using Cp/Cpk and Pp/Ppk indices.
• Non-normal distributions. Calculating capability and performance indices based on the normal distribution model when the data being analyzed does not follow such a distribution is a common mistake. The new manual emphasizes calculating indices with prior consideration of the distribution type. The methodology has been aligned with ISO 22514, including the General Geometric Method and the Exceedance Proportion Method/z-Score/Bothe Method.
• Control charts. Control chart formulas have been updated. The ability to calculate control limits using a significance level α (alpha) has been added, which can be used to adjust the "sensitivity" of control charts. This provides greater flexibility in setting limits compared to the rigid approach dependent solely on sample size. It is now possible to create control charts based on process data (process-related) as well as based on the expected process behavior (tolerance-related).
• Software validation requirements. A dedicated chapter has been devoted to the verification and validation of SPC software tools. This is a critical topic given the widespread use of digital and automated data collection - especially in the context of Industry 4.0 and AI integration.

Summary

The AIAG & VDA SPC Yellow Volume signals that a significant modernization of SPC practices in the automotive industry is on the way. The document harmonizes AIAG and VDA requirements while adding a solid foundation from ISO standards, making it a solution that goes beyond "automotive" - it has the potential to become an excellent SPC reference manual for other industries as well.

The inclusion of topics such as SPC software, reporting, traceability, and record retention reflects the integration with automated data collection systems, MES, the broader scope of Industry 4.0, and AI tools.

The AIAG & VDA SPC Yellow Volume is available for free download from the VDA and AIAG websites.

And a final note for quality engineers and process engineers: it's going to be very interesting... :)