Procurement Glossary
Initial Sample Inspection Report (ISIR): Definition and application in Procurement
November 19, 2025
The Initial Sample Inspection Report (ISIR) is a central document in procurement quality management that documents the initial sampling of new supplier parts. This inspection report confirms that components or products meet all specified requirements before they go into series production. Find out below what an ISIR involves, which process steps are required and how you can use it to minimize quality risks.
Key Facts
- ISIR documents the complete testing of initial samples before series release
- Contains measurement results, material certificates and process certificates from the supplier
- Reduces quality risks through systematic pre-validation
- Standardized according to AIAG guidelines for automotive suppliers
- Basis for series release decisions and supplier evaluation
Contents
What is an Initial Sample Inspection Report (ISIR)?
The ISIR is a comprehensive documentation of the initial sampling that records all relevant quality characteristics of a new component or product.
Core components of the ISIR
A complete ISIR comprises several essential components:
- Dimensional inspection reports with all critical dimensions
- Material certificates and material certificates
- Functional tests and performance tests
- Process documentation and control plans
ISIR vs. other quality documents
In contrast to ongoing quality inspections, the ISIR focuses exclusively on initial validation. While incoming goods inspections are carried out continuously, the ISIR is only created for new parts, changes or after longer production breaks.
Importance of ISIR in Procurement
For purchasers, the ISIR forms the basis for well-founded supplier decisions. It enables an objective assessment of supplier capabilities and minimizes the risk of quality problems in series production. It also supports series production approval and provides legal protection.
Process steps and responsibilities
ISIR creation follows a structured process with clearly defined responsibilities between Procurement, Quality and the supplier.
Preparation and definition of requirements
Procurement defines the test requirements together with Development and communicates these to the supplier. Critical characteristics, test methods and documentation requirements are defined. An inspection instruction specifies the expectations.
Implementation by the supplier
The supplier carries out the initial sampling and systematically documents all results:
- Dimensional measurements with calibrated test equipment
- Material and surface testing
- Function and load tests
- Process validation and proof of machine capability
Evaluation and release
Quality Management checks the submitted ISIR for completeness and conformity. In the event of deviations, a deviation approval is required or a rectification is requested. Only after a successful assessment is the series release issued.
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Important KPIs for ISIR
The effectiveness of the ISIR process can be measured and continuously improved using various key figures.
Quality indicators
The ISIR success rate shows the proportion of reports accepted on the first attempt. High rework rates indicate deficits in supplier preparation. The Cpk values from the process capability analysis provide information about the stability of the production processes.
Process efficiency metrics
Throughput times from ISIR receipt to release decision measure process efficiency:
- Average processing time per ISIR
- Proportion of valuations completed on time
- Resources required per initial sampling
Long-term quality indicators
The true success of an ISIR is reflected in the series quality. Quality costs due to rework, complaints or recalls should be minimal if the ISIR is carried out properly. The correlation between ISIR quality and subsequent series problems is an important indicator of process validity.
Risks, dependencies and countermeasures
Despite its importance, the ISIR process harbours various risks that must be minimized through appropriate measures.
Incomplete or incorrect documentation
A lack of care when creating an ISIR can lead to overlooked quality problems. Standardized checklists and audit checklists help to systematically check all relevant aspects. Regular supplier audits ensure competence.
Time pressure and lack of resources
Tight project deadlines lead to ISIR processes being shortened or carried out superficially. This significantly increases the risk of serial problems:
- Insufficient sample sizes
- Lack of long-term tests
- Superficial process validation
Supplier dependencies
The quality of the ISIR depends largely on the competence and equipment of the supplier. Test equipment management and regular calibrations are essential. Independent validation by third-party laboratories should be considered for critical parts.
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Practical example
An automotive supplier develops a new plastic component for interior fittings. Once the mold development is complete, the supplier creates a comprehensive ISIR with dimensional measurements, material certificates and surface inspections. The initial sampling includes 50 parts from different cavities to validate the mold quality. In addition, ageing tests and UV resistance tests are carried out.
- Complete documentation of all critical features
- Proof of process capability through statistical evaluation
- Release only after successful ISIR assessment
Current developments and effects
ISIR practice is constantly evolving, driven by technological advances and increasing quality requirements.
Digitization of ISIR processes
Modern companies are increasingly relying on digital ISIR platforms that enable automated data collection and analysis. AI-based systems support anomaly detection and trend analysis, allowing potential quality problems to be identified at an early stage.
Integration in Industry 4.0
The networking of production systems enables real-time transmission of measurement data directly to the ISIR. Statistical process controls are generated automatically and deviations are detected immediately. This significantly reduces manual effort.
Advanced analysis methods
New inspection technologies such as 3D scanning and optical measurement technology are expanding the possibilities for initial sampling. At the same time, the requirements for traceability and depth of documentation are increasing, particularly in regulated industries such as medical technology.
Conclusion
The Initial Sample Inspection Report forms the foundation for quality-assured procurement processes and minimizes series risks through systematic pre-validation. Its proper implementation requires clear processes, competent suppliers and consistent evaluation. Digital technologies and AI support will further increase ISIR efficiency and open up new analysis options. For buyers, the ISIR remains an indispensable tool for supplier evaluation and quality assurance.
FAQ
What distinguishes ISIR from PPAP?
ISIR is a component of the PPAP process (Production Part Approval Process). While PPAP covers the entire approval process, ISIR focuses specifically on the documentation of initial sampling results. PPAP also includes aspects such as process FMEA and control plans.
When is a new ISIR required?
A new ISIR is required in the event of design changes, tool modifications, supplier changes or after longer production breaks. A new initial sampling is also required in the event of process changes or new production locations. The exact trigger criteria should be defined in the quality agreement.
How long is an ISIR valid for?
The validity of an ISIR depends on various factors, typically 2-5 years with unchanged production. Shorter intervals may be required for critical safety parts. Changes to the product, process or supplier make an update necessary.
What sample size is appropriate?
The sample size depends on the criticality of the component and the statistical requirements. For dimensional inspections, at least 25-50 parts are usual, or more for critical characteristics. Sampling tests follow statistical principles to ensure validity.
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